Co-reporter:Pengcheng Zhou, Zhimin Fang, Weiran Zhou, Qiquan Qiao, Mingtai Wang, Tao Chen, and Shangfeng Yang
ACS Applied Materials & Interfaces September 27, 2017 Volume 9(Issue 38) pp:32957-32957
Publication Date(Web):September 7, 2017
DOI:10.1021/acsami.7b12135
The interfaces between perovskite layer and electrodes play a crucial role on efficient charge transport and extraction in perovskite solar cells (PSCs). Herein, for the first time we applied a low-cost nonconjugated polymer poly(vinylpyrrolidone) (PVP) as a new interlayer between PCBM electron transport layer (ETL) and Ag cathode for high-performance inverted planar heterojunction perovskite solar cells (iPSCs), leading to a dramatic efficiency enhancement. The CH3NH3PbI3–xClx-based iPSC device incorporating the PVP interlayer exhibited a power conversion efficiency (PCE) of 12.55%, which is enhanced by ∼15.9% relative to that of the control device without PVP interlayer (10.83%). The mechanistic investigations based on morphological, optical, and impedance spectroscopic characterizations reveal that incorporation of PVP interlayer promotes electron transport across the CH3NH3PbI3–xClx perovskite/Ag interface via PCBM ETL. Besides, PVP incorporation induces the formation of a dipole layer, which may enhance the built-in potential across the device, conjunctly promoting electron transport from PCBM to Ag cathode and consequently leading to significantly improved fill factor (FF) from 58.98 to 66.13%.Keywords: dipole layer; electron transport layer; interface engineering; perovskite solar cells; poly(vinylpyrrolidone);
Co-reporter:Sheng-Peng Jiang, Mengmeng Zhang, Cheng-Yu Wang, Shangfeng Yang, and Guan-Wu Wang
Organic Letters October 6, 2017 Volume 19(Issue 19) pp:
Publication Date(Web):September 14, 2017
DOI:10.1021/acs.orglett.7b02343
The copper-promoted cascade radical reaction of N-sulfonyl-2-allylanilines with [60]fullerene has been developed to efficiently provide novel and scarce (2-indolinyl)methylated hydrofullerenes, featuring a broad substrate scope and excellent functional group tolerance. A plausible reaction mechanism for the formation of (2-indolinyl)methylated hydrofullerenes is proposed on the basis of the experimental results. In addition, further transformation into other carbocyclic derivatives of [60]fullerene as well as their applications in organic photovoltaic devices of the obtained products has also been explored.
Co-reporter:Fei Jin, Shangfeng Yang, and Sergey I. Troyanov
Inorganic Chemistry May 1, 2017 Volume 56(Issue 9) pp:4780-4780
Publication Date(Web):April 17, 2017
DOI:10.1021/acs.inorgchem.7b00568
Fullerene C98 possesses 259 isomers obeying the isolated pentagon rule (IPR), from which two, nos. 116 and 248, have been confirmed earlier as chloro derivatives. High-temperature chlorination of C98-containing mixtures afforded crystals of several chloro derivatives, and their structure elucidation by X-ray crystallography revealed the presence of new isomers, nos. 107, 109, and 120, in the fullerene soot. Evidence for an isomer of no. 111 is also presented. In addition, a new chloride of the known isomer 248 has been isolated and structurally studied. The chlorination patterns of the chlorides are discussed in terms of the formation of isolated C═C bonds and aromatic substructures on the fullerene cages.
Co-reporter:Fei Jin, Shangfeng Yang, Erhard Kemnitz, and Sergey I. Troyanov
Journal of the American Chemical Society April 5, 2017 Volume 139(Issue 13) pp:4651-4651
Publication Date(Web):March 24, 2017
DOI:10.1021/jacs.7b01490
A classical fullerene is composed of hexagons and pentagons only, and its stability is generally determined by the Isolated-Pentagon-Rule (IPR). Herein, high-temperature chlorination of a mixture containing a classical IPR-obeying fullerene C88 resulted in isolation and X-ray crystallographic characterization of non-IPR, nonclassical (NC) fullerene chloride C84(NC2)Cl30 (1) containing two heptagons. The carbon cage in C84(NC2)Cl30 contains 14 pentagons, 12 of which form two pairs of fused pentagons and two groups of quaternary sequentially fused pentagons, which have never been observed in reported carbon cages. All 30 Cl atoms form an unprecedented single chain of ortho attachments on the C84 cage. A reconstruction of the pathway of the chlorination-promoted skeletal transformation revealed that the previously unknown IPR isomer C88(3) is converted into 1 by two losses of C2 fragments followed by two Stone–Wales rearrangements, resulting in the formation of very stable chloride with rather short C–Cl bonds.
Co-reporter:Xianjun Zhu;Taiming Zhang;Zijun Sun;Huanlin Chen;Jian Guan;Xiang Chen;Hengxing Ji;Pingwu Du
Advanced Materials 2017 Volume 29(Issue 17) pp:
Publication Date(Web):2017/05/01
DOI:10.1002/adma.201605776
Metal-free elemental photocatalysts for hydrogen (H2) evolution are more advantageous than the traditional metal-based inorganic photocatalysts since the nonmetal elements are generally cheaper, more earth-abundant, and environmentally friendly. Black phosphorus (BP) has been attracting increasing attention in recent years based on its anisotropic 2D layered structure with tunable bandgap in the range of 0.3–2.0 eV; however, the application of BP for photocatalytic H2 evolution has been scarcely reported experimentally although being theoretically predicted. Herein, for the first time, the visible light photocatalytic H2 evolution of BP nanosheets prepared via a facile solid-state mechanochemical method by ball-milling bulk BP is reported. Without using any noble metal cocatalyst, the visible light photocatalytic hydrogen evolution rate of BP nanosheets reaches 512 µmol h−1 g−1, which is ≈18 times higher than that of the bulk BP, and is comparable or even higher than that of graphitic carbon nitrides (g-C3N4).
Co-reporter:Shangfeng Yang;Tao Wei;Fei Jin
Chemical Society Reviews 2017 vol. 46(Issue 16) pp:5005-5058
Publication Date(Web):2017/08/14
DOI:10.1039/C6CS00498A
Fullerenes have the characteristic of a hollow interior, and this unique feature triggers intuitive inspiration to entrap atoms, ions or clusters inside the carbon cage in the form of endohedral fullerenes. In particular, upon entrapping an otherwise unstable metal cluster into a carbon cage, the so-called endohedral clusterfullerenes fulfil the mutual stabilization of the inner metal cluster and the outer fullerene cage with a specific isomeric structure which is often unstable as an empty fullerene. A variety of metal clusters have been reported to form endohedral clusterfullerenes, including metal nitrides, carbides, oxides, sulfides, cyanides and so on, making endohedral clusterfullerenes the most variable and intriguing branch of endohedral fullerenes. In this review article, we present an exhaustive review on all types of endohedral clusterfullerenes reported to date, including their discoveries, syntheses, separations, molecular structures and properties as well as their potential applications in versatile fields such as biomedicine, energy conversion, and so on. At the end, we present an outlook on the prospect of endohedral clusterfullerenes.
Co-reporter:Weiran Zhou;Jieming Zhen;Qing Liu;Zhimin Fang;Dan Li;Pengcheng Zhou;Tao Chen
Journal of Materials Chemistry A 2017 vol. 5(Issue 4) pp:1724-1733
Publication Date(Web):2017/01/24
DOI:10.1039/C6TA07876A
Interfacial engineering is critical for highly efficient charge carrier transport in perovskite solar cells (PSCs). Herein, we developed a new method, called successive surface engineering, that affords PSCs with enhanced efficiency and dramatically suppressed current–voltage hysteresis. Upon modifying the TiO2 compact layer, which is commonly used as an electron transport layer (ETL) in regular-structure (n–i–p) planar heterojunction (PHJ) PSCs, by successively incorporating [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) and an ethanolamine (ETA)-functionalized fullerene (C60-ETA) synthesized facilely via a one-pot nucleophilic addition reaction, the average power conversion efficiency (PCE) of the CH3NH3PbI3-based PHJ-PSC devices increased from 13.00% to 16.31%; the best PCE attained was 18.49%, which, to our knowledge, represents the highest PCE reported to date for regular-structure PHJ-PSCs devices based on fullerene-modified TiO2 interlayers. In contrast, single surface engineering of the TiO2 layer with a PC61BM or C60-ETA layer alone results in only negligible changes in PCE, revealing the synergistic effect of these two fullerene derivatives: the PC61BM layer can passivate the traps on the TiO2 surface, while the subsequent C60-ETA layer not only improves the wettability of the perovskite film on the ETL but also facilitates electron transport across the interface between the perovskite and the TiO2 ETL. The structural and morphological characterizations show that following dual surface modification of the TiO2 layer with PC61BM and C60-ETA, both the surface coverage and crystallinity of the CH3NH3PbI3 perovskite film are improved. Steady-state photoluminescence decay and electrochemical impedance spectroscopic studies manifest that the dual surface modification substantially improves the charge extraction efficiency and suppresses charge recombination. As a consequence, this dual surface modification leads to an obvious increase of the short-circuit current density (Jsc), which contributes primarily to the PCE enhancement. Additionally, because PC61BM may induce passivation of the traps on the TiO2 surface and in the perovskite layer, remarkably, the hysteresis of the current–voltage response is dramatically suppressed following the dual surface modification.
Co-reporter:Zuo Xiao, Xue Jia, Dan Li, Shizhe Wang, ... Liming Ding
Science Bulletin 2017 Volume 62, Issue 22(Volume 62, Issue 22) pp:
Publication Date(Web):30 November 2017
DOI:10.1016/j.scib.2017.10.017
Co-reporter:Xiang Chen;Huanlin Chen;Jian Guan;Jieming Zhen;Zijun Sun;Pingwu Du;Yalin Lu
Nanoscale (2009-Present) 2017 vol. 9(Issue 17) pp:5615-5623
Publication Date(Web):2017/05/04
DOI:10.1039/C7NR01237C
Graphitic carbon nitride (g-C3N4) as an emerging two-dimensional (2D) nanomaterial has been commonly used as a metal-free photocatalyst with potential applications in visible light photocatalytic water-splitting. However, the photocatalytic activity of g-C3N4 is quite low due to its relatively large band gap and the existence of contact resistance between the nanosheets. Herein we report for the first time the facile synthesis of a covalently bonded g-C3N4/C60 hybrid via a solid-state mechanochemical route and its application in photocatalytic hydrogen production under visible light. The g-C3N4/C60 hybrid was synthesized by ball-milling g-C3N4 and C60 in the presence of lithium hydroxide (LiOH) as a catalyst. The hybrid nature and conformation of the g-C3N4/C60 hybrid were confirmed by a series of spectroscopic and morphological studies, featuring the covalent bonding of C60 onto the edges of g-C3N4 nanosheets via a four-membered ring of azetidine, which has never been reported in fullerene chemistry. The g-C3N4/C60 hybrid was further applied to metal-free visible light photocatalytic hydrogen production, affording a H2 production rate of 266 μmol h−1 g−1 without using any noble metal cocatalyst such as Pt, which is about 4.0 times higher than that obtained for the pristine g-C3N4 photocatalyst.
Co-reporter:Dan Li, Qing Liu, Jieming Zhen, Zhimin Fang, Xiang Chen, and Shangfeng Yang
ACS Applied Materials & Interfaces 2017 Volume 9(Issue 3) pp:
Publication Date(Web):January 3, 2017
DOI:10.1021/acsami.6b13461
By using a facile one-pot nucleophilic addition reaction, we synthesized a novel imidazole (IMZ)-functionalized fullerene (C60-IMZ), and applied it as a third component of inverted ternary polymer solar cells (PSCs), leading to dramatic efficiency enhancement. According to FT-IR, XPS spectroscopic characterizations, and elemental analysis, the chemical structure of C60-IMZ was determined with the average IMZ addition number estimated to be six. The lowest unoccupied molecular orbital (LUMO) level of C60-IMZ measured by cyclic voltammetry was −3.63 eV, which is up-shifted relative to that of 6,6-phenyl C61-butyric acid methyl ester (PC61BM). Upon doping C60-IMZ as a third component into an active layer blend of poly(3-hexylthiophene) (P3HT) and PC61BM, the power conversion efficiency (PCE) of the inverted ternary PSCs was 3.4% under the optimized doping ratio of 10 wt %, dramatically higher than that of the control device ITO/P3HT:PC61BM/MoO3/Ag based on the binary P3HT:PC61BM blend (1.3%). The incorporation of C60-IMZ results in enhancement of the absorption of P3HT:PC61BM blend film, increase of the electron mobility of the device, and rougher film surface of the P3HT:PC61BM active layer beneficial for interfacial contact with the Ag anode. Furthermore, C60-IMZ doped in P3HT:PC61BM blend may migrate to the surface of ITO cathode via vertical phase separation as revealed by XPS depth analysis, consequently forming a cathode interfacial layer (CIL), which can lower the work function (WF) of ITO cathode. Thus, the interfacial contact between the active layer and ITO cathode is improved, facilitating electron transport from the active layer to ITO cathode. The effectiveness of C60-IMZ as a vertically phase-separated CIL on efficiency enhancement of inverted ternary PSCs is further verified by doping it into another active layer system comprised of a low-bandgap conjugated polymer, poly(thieno[3,4-b]-thiophene/benzodithiophene) (PTB7), blended with [6,6]-phenyl C71-butyric acid methyl ester (PC71BM). Under the optimized C60-IMZ doping ratio of 10 wt %, the PCE of the PTB7:PC71BM-based inverted ternary PSC device reaches 5.3%, which is about 2 times higher than that of the control binary device (2.6%).Keywords: cathode interfacial layer; electron transport; fullerene derivative; ternary polymer solar cells; vertical phase separation;
Co-reporter:Fei Jin;Dr. Song Wang;Dr. Nadezhda B. Tamm; Dr. Shangfeng Yang; Dr. Sergey I. Troyanov
Angewandte Chemie International Edition 2017 Volume 56(Issue 39) pp:11990-11994
Publication Date(Web):2017/09/18
DOI:10.1002/anie.201707298
AbstractAs an emerging member of endohedral fullerenes, metal cyanide clusterfullerenes (CYCF) are unique in terms of the encapsulation of a monometallic cluster. To date the reported carbon cages of CYCFs are limited to C82 and C76, and little is known about the chemical reactivity of CYCFs. Herein, two isomers of the first C84-based CYCFs, YCN@C84, were isolated as trifluoromethyl derivatives, including YCN@C84(23)(CF3)18 and three isomers of YCN@C84(13)(CF3)16, which are based on a unique chiral C2-C84(13) cage. As a common feature of the CF3 addition patterns, the YCN@C84(CF3)16/18 compounds are stabilized by the formation of isolated C=C bonds and benzenoid rings on the carbon cages. The interplay between the endohedral YCN cluster and the exhohedral CF3 addends was unveiled according to single-crystal X-ray diffraction studies, thus offering new insight into the chemical reactivity of CYCFs.
Co-reporter:Fupin Liu, Fei Jin, Song Wang, Alexey A. Popov, Shangfeng Yang
Inorganica Chimica Acta 2017 Volume 468(Volume 468) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.ica.2017.04.027
•A new entrant of carbido clusterfullerene, TiTb2C@Ih(7)-C80, was synthesized and isolated successfully.•The molecular structure of TiTb2C@Ih(7)-C80 was determined unambiguously by single crystal X-ray diffraction.•TiTb2C represents the first pyramidal cluster found for carbido clusterfullerenes.•The electrochemical analyses on TiM2C@Ih(7)-C80 unraveled the self-adaptive structural transformations.Interplay between the encapsulated cluster and fullerene cage is crucial for the stability of endohedral clusterfullerene. Herein we report the synthesis and isolation of a new entrant of carbido clusterfullerene, TiTb2C@Ih(7)-C80. The molecular structure of TiTb2C@Ih(7)-C80 was determined unambiguously by single crystal X-ray diffraction, featuring a pyramidal TiTb2C cluster encapsulated within the popular Ih(7)-C80 cage. To our knowledge, TiTb2C represents the first pyramidal cluster found for carbido clusterfullerenes. On the basis of a comparative study with the reported TiM2C@Ih(7)-C80 (M = Sc, Lu) carbido clusterfullerenes and M3N@Ih(7)-C80 (M = Sc, Y and lanthanide) nitride clusterfullerenes, we tentatively determined the borderline of the sum of the three M-C(N) bond lengths of M3N/C for the encapsulated M3N/C cluster changing from planar to pyramidal geometry as 6.15–6.20 Å. The electrochemical analyses on TiM2C@Ih(7)-C80 unraveled the self-adaptive structural transformations existing in the TiM2C@Ih(7)-C80 (M = Er, Y, Dy and Tb) based on their similar cluster-cage strain evaluated through electrochemical measurements.Download high-res image (172KB)Download full-size image
Co-reporter:Fei Jin;Dr. Song Wang;Dr. Nadezhda B. Tamm; Dr. Shangfeng Yang; Dr. Sergey I. Troyanov
Angewandte Chemie 2017 Volume 129(Issue 39) pp:12152-12156
Publication Date(Web):2017/09/18
DOI:10.1002/ange.201707298
AbstractAs an emerging member of endohedral fullerenes, metal cyanide clusterfullerenes (CYCF) are unique in terms of the encapsulation of a monometallic cluster. To date the reported carbon cages of CYCFs are limited to C82 and C76, and little is known about the chemical reactivity of CYCFs. Herein, two isomers of the first C84-based CYCFs, YCN@C84, were isolated as trifluoromethyl derivatives, including YCN@C84(23)(CF3)18 and three isomers of YCN@C84(13)(CF3)16, which are based on a unique chiral C2-C84(13) cage. As a common feature of the CF3 addition patterns, the YCN@C84(CF3)16/18 compounds are stabilized by the formation of isolated C=C bonds and benzenoid rings on the carbon cages. The interplay between the endohedral YCN cluster and the exhohedral CF3 addends was unveiled according to single-crystal X-ray diffraction studies, thus offering new insight into the chemical reactivity of CYCFs.
Co-reporter:Fupin Liu, Cong-Li Gao, Qingming Deng, Xianjun Zhu, Aram Kostanyan, Rasmus Westerström, Song Wang, Yuan-Zhi Tan, Jun Tao, Su-Yuan Xie, Alexey A. Popov, Thomas Greber, and Shangfeng Yang
Journal of the American Chemical Society 2016 Volume 138(Issue 44) pp:14764-14771
Publication Date(Web):October 18, 2016
DOI:10.1021/jacs.6b09329
Clusterfullerenes are capable of entrapping a variety of metal clusters within carbon cage, for which the entrapped metal cluster generally keeps its geometric structure (e.g., bond distance and angle) upon changing the isomeric structure of fullerene cage, and whether the properties of the entrapped metal cluster is geometry-dependent remains unclear. Herein we report an unusual triangular monometallic cluster entrapped in fullerene cage by isolating several novel terbium cyanide clusterfullerenes (TbNC@C82) with different cage isomeric structures. Upon varying the isomeric structure of C82 cage from C2(5) to Cs(6) and to C2v(9), the entrapped triangular TbNC cluster exhibits significant distortions as evidenced by the changes of Tb–C(N) and C–N bond distances and variation of the Tb–C(N)–N(C) angle by up to 20°, revealing that the geometric structure of the entrapped triangular TbNC cluster is variable. All three TbNC@C82 molecules are found to be single-ion magnets, and the change of the geometric structure of TbNC cluster directly leads to the alternation of the magnetic relaxation time of the corresponding TbNC@C82 clusterfullerene.
Co-reporter:Xiang Chen;Qing Liu;Qiliang Wu;Pingwu Du;Jun Zhu;Songyuan Dai
Advanced Functional Materials 2016 Volume 26( Issue 11) pp:1719-1728
Publication Date(Web):
DOI:10.1002/adfm.201505321
Graphitic carbon nitride (g-C3N4) has been commonly used as photocatalyst with promising applications in visible-light photocatalytic water-splitting. Rare studies are reported in applying g-C3N4 in polymer solar cells. Here g-C3N4 is applied in bulk heterojunction (BHJ) polymer solar cells (PSCs) for the first time by doping solution-processable g-C3N4 quantum dots (C3N4 QDs) in the active layer, leading to a dramatic efficiency enhancement. Upon C3N4 QDs doping, power conversion efficiencies (PCEs) of the inverted BHJ-PSC devices based on different active layers including poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PC61BM), poly(4,8-bis-alkyloxybenzo(l,2-b:4,5-b′)dithiophene-2,6-diylalt-(alkyl thieno(3,4-b)thiophene-2-carboxylate)-2,6-diyl):[6,6]-phenyl C71-butyric acid methyl ester (PBDTTT-C:PC71BM), and poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-co-3-fluorothieno [3,4-b]thiophene-2-carboxylate] (PTB7-Th):PC71BM reach 4.23%, 6.36%, and 9.18%, which are enhanced by ≈17.5%, 11.6%, and 11.8%, respectively, compared to that of the reference (undoped) devices. The PCE enhancement of the C3N4 QDs doped BHJ-PSC device is found to be primarily attributed to the increase of short-circuit current (Jsc), and this is confirmed by external quantum efficiency (EQE) measurements. The effects of C3N4 QDs on the surface morphology, optical absorption and photoluminescence (PL) properties of the active layer film as well as the charge transport property of the device are investigated, revealing that the efficiency enhancement of the BHJ-PSC devices upon C3N4 QDs doping is due to the conjunct effects including the improved interfacial contact between the active layer and the hole transport layer due to the increase of the roughness of the active layer film, the facilitated photoinduced electron transfer from the conducting polymer donor to fullerene acceptor, the improved conductivity of the active layer, and the improved charge (hole and electron) transport.
Co-reporter:Jieming Zhen, Qing Liu, Xiang Chen, Dan Li, Qiquan Qiao, Yalin Lu and Shangfeng Yang
Journal of Materials Chemistry A 2016 vol. 4(Issue 21) pp:8072-8079
Publication Date(Web):21 Apr 2016
DOI:10.1039/C6TA02016J
An ethanolamine (ETA)-functionalized fullerene (C60-ETA) was synthesized by using a facile one-pot addition reaction, and applied as an efficient electron transport layer (ETL) for inverted polymer solar cells (iPSCs) with the efficiency exceeding 9.5%, which represents the highest power conversion efficiency (PCE) reported so far for iPSC devices with independent fullerene derivative ETLs. The chemical structure of C60-ETA was studied by FT-IR and XPS spectroscopies and elemental analysis, and the average molecular formula of C60-ETA is estimated to be C60(NHC2H4OH)8(H)8 with an average ETA addition number of eight. C60-ETA was applied as an ETL for bulk heterojunction (BHJ) iPSC devices based on different photoactive layers including poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]:[6,6]-phenyl C71-butyric acid methyl ester (PTB7-Th:PC71BM), poly(4,8-bis-alkyloxybenzo(l,2-b:4,5-b′)dithiophene-2,6-diylalt-(alkyl thieno(3,4-b)thiophene-2-carboxylate)-2,6-diyl) (PBDTTT-C):PC71BM and poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PC61BM), leading to the best PCE of 9.55%, 6.50% and 4.18%, respectively, which are all higher than those of the corresponding reference devices based on the ZnO ETL. The PCE improvement of the C60-ETA device relative to that of the ZnO device primarily originates from the increase of short-circuit current density (Jsc), which is due to the smoothened ETL surface and the increase of electron mobility, facilitating electron transport from the active layer to the ITO cathode.
Co-reporter:Qiliang Wu, Pengcheng Zhou, Weiran Zhou, Xiangfeng Wei, Tao Chen, and Shangfeng Yang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 24) pp:15333-15340
Publication Date(Web):June 2, 2016
DOI:10.1021/acsami.6b03276
A two-step method has been popularly adopted to fabricate a perovskite film of planar heterojunction organo-lead halide perovskite solar cells (PSCs). However, this method often generates uncontrollable film morphology with poor coverage. Herein, we report a facile method to improve perovskite film morphology by incorporating a small amount of acetate (CH3COO–, Ac–) salts (NH4Ac, NaAc) as nonhalogen additives in CH3NH3I solution used for immersing PbI2 film, resulting in improved CH3NH3PbI3 film morphology. Under the optimized NH4Ac additive concentration of 10 wt %, the best power conversion efficiency (PCE) reaches 17.02%, which is enhanced by ∼23.2% relative to that of the pristine device without additive, whereas the NaAc additive does not lead to an efficiency enhancement despite the improvement of the CH3NH3PbI3 film morphology. SEM study reveals that NH4Ac and NaAc additives can both effectively improve perovskite film morphology by increasing the surface coverage via diminishing pinholes. The improvement on CH3NH3PbI3 film morphology is beneficial for increasing the optical absorption of perovskite film and improving the interfacial contact at the perovskite/spiro-OMeTAD interface, leading to the increase of short-circuit current and consequently efficiency enhancement of the PSC device for NH4Ac additive only.
Co-reporter:Song Wang, Shangfeng Yang, Erhard Kemnitz, and Sergey I. Troyanov
Inorganic Chemistry 2016 Volume 55(Issue 12) pp:5741
Publication Date(Web):June 8, 2016
DOI:10.1021/acs.inorgchem.6b00809
High temperature chlorination of HPLC fractions of higher fullerenes followed by single crystal X-ray diffraction with the use of synchrotron radiation resulted in the structure determination of IPR C106(1155)Cl24 and IPR C108(1771)Cl12. C106(1155)Cl24 is cocrystallized with C104Cl24, a chloride of the nonclassical isomer of C104. The moderately stable isomer C106(1155) and the most stable C108(1771) represent so far the largest pristine fullerenes with known cages.
Co-reporter:Qing Liu, Jieming Zhen, Weiran Zhou, Xiang Chen, Dan Li, Shangfeng Yang
Organic Electronics 2016 Volume 39() pp:191-198
Publication Date(Web):December 2016
DOI:10.1016/j.orgel.2016.10.009
•A fullerene derivative C60-ETA was applied as an effective CBL in conventional-structure BHJ-PSC devices.•C60-ETA is a universal CBL in PTB7-Th:PC71BM, PTB7:PC71BM and PBDTTT-C:PC71BM active layer systems.•The best PCE of the C60-ETA CBL-based devices reaches 9.66%, surpassing Ca in terms of CBL performance.•C60-ETA CBL may induce improvements on both the interfacial contact and electron transport.Cathode buffer layer (CBL) introduced between the active layer and cathode is crucial for selectively transporting electrons and blocking holes for polymer solar cells (PSCs). Calcium (Ca) is the most commonly used CBL in conventional-structure bulk heterojunction (BHJ) PSC devices, but is prone to oxidation due to its high reactivity, inhibiting its practical applications. Herein, we applied an alcohol-soluble fullerene aminoethanol derivative (C60-ETA) as an efficient CBL surpassing Ca in conventional-structure BHJ-PSC devices, leading to obvious efficiency enhancement with the best power conversion efficiency (PCE) reaching 9.66%. C60-ETA CBL was applied in PSC devices based on three different photoactive layer systems, including poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]:[6,6]-phenyl C71-butyric acid methyl ester (PTB7-Th:PC71BM), polythieno[3,4-b]thiophene-co-benzodithiophene (PTB7):PC71BM and poly(4,8-bis-alkyloxybenzo(l,2-b:4,5-b′)dithiophene-2,6-diylalt-(alkylthieno(3,4-b)thiophene-2-carboxylate)-2,6-diyl) (PBDTTT-C):PC71BM, affording the best PCE of 9.66%, 8.51% and 7.19%, respectively, which are all higher than those of the corresponding devices based on the commonly used Ca CBL. The mechanism of efficiency enhancement of C60-ETA CBL relative to Ca is studied, revealing that C60-ETA CBL may induce improvements on both the interfacial contact between the active layer/cathode and electron transport, facilitating electron extraction by the Al cathode, and consequently leading to the increase of short-circuit current density (Jsc), which contributes primarily to the PCE improvement.An alcohol-soluble fullerene derivative functionalized by 2-aminoethanol (C60-ETA) via a facile one-pot reaction was applied as an efficient CBL surpassing Ca in conventional-structure bulk heterojunction polymer solar cell (BHJ-PSC) devices, leading to obvious efficiency enhancement with the best power conversion efficiency (PCE) reaching 9.66%. C60-ETA CBL may induce improvements on both the interfacial contact between the active layer/cathode and electron transport, facilitating electron extraction by the Al cathode, and consequently leading to the increase of short-circuit current density (Jsc), which contributes primarily to the PCE improvement.
Co-reporter:Fei Jin, Song Wang, Shangfeng YangNadezhda B. Tamm, Ilya N. Ioffe, Sergey I. Troyanov
Inorganic Chemistry 2016 Volume 55(Issue 24) pp:
Publication Date(Web):December 6, 2016
DOI:10.1021/acs.inorgchem.6b02556
Recently discovered monometallic cyanide cluster fullerenes are a novel family of endohedral molecules, whose chemical reactivity has not yet been probed. High-temperature trifluoromethylation of the yttrium cyanide cluster fullerene YCN@C82(6), followed by high-performance liquid chromatography separation and an X-ray diffraction study of the two crystallized fractions, resulted in the structural characterization of YCN@C82(6)(CF3)16/18. In both molecules, exohedrally attached CF3 groups delimit the spherical π system into localized double bonds, benzenoid rings, larger aromatic assemblies, and a conjugated fragment with the only intact pentagon that is involved in coordination to the interior Y atom. We also present theoretical results on charge distributions in the compounds reported.
Co-reporter:Qiliang Wu, Weiran Zhou, Qing Liu, Pengcheng Zhou, Tao Chen, Yalin Lu, Qiquan Qiao, and Shangfeng Yang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 50) pp:
Publication Date(Web):November 28, 2016
DOI:10.1021/acsami.6b12683
Inorganic metal oxide, especially TiO2, has been commonly used as an electron transport layer (ETL) in regular-structure (n-i-p) planar heterojunction perovskite solar cells (PHJ-PSCs) but generally suffers from high electron recombination rate and incompatibility with low-temperature solution processability. Herein, by applying an ionic liquid (IL, 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMIM]PF6)) as either a TiO2-modifying interlayer or an independent ETL, we investigated systematically IL interface engineering for PHJ-PSCs. Upon spin-coating [EMIM]PF6-IL onto TiO2 ETL as a modification layer, the average power conversion efficiency (PCE) of CH3NH3PbI3 PHJ-PSC devices reaches 18.42 ± 0.65%, which dramatically surpasses that based on commonly used TiO2 ETL (14.20 ± 0.43%), and the highest PCE (19.59%) is almost identical to that of the record PCE for planar CH3NH3PbI3 PSCs (19.62%) reported very recently. On the other hand, by applying [EMIM]PF6-IL as an independent ETL, we achieved an average PCE of 13.25 ± 0.55%, and the highest PCE (14.39%) approaches that obtained for PHJ-PSCs based on independent TiO2 ETL (14.96%). Both IL interface engineering methods reveal the effective electron transport of [EMIM]PF6-IL. The effects of [EMIM]PF6-IL on the surface morphology, crystallinity, and optical absorption of the perovskite film and the interface between the perovskite layer and substrate were investigated and compared with the case of independent TiO2 ETL, revealing the role of [EMIM]PF6-IL in efficient electron transport.Keywords: dipolar interaction; electron transport layer; interface engineering; ionic liquid; perovskite solar cells;
Co-reporter:Song Wang;Dr. Shangfeng Yang;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Angewandte Chemie 2016 Volume 128( Issue 10) pp:3512-3515
Publication Date(Web):
DOI:10.1002/ange.201511928
Abstract
High-temperature chlorination of C100 fullerene followed by X-ray structure determination of the chloro derivatives enabled the identification of three isomers of C100 from the fullerene soot, specifically numbers 18, 425, and 417, which obey the isolated pentagon rule (IPR). Among them, isomers C1-C100(425) and C2-C100(18) afforded C1-C100(425)Cl22 and C2-C100(18)Cl28/30 compounds, respectively, which retain their IPR cage connectivities. In contrast, isomer C2v-C100(417) gives Cs-C100(417)Cl28 which undergoes a skeletal transformation by the loss of a C2 fragment, resulting in the formation of a nonclassical (NC) C1-C98(NC)Cl26 with a heptagon in the carbon cage. Most probably, two nonclassical C1-C100(NC)Cl18/22 chloro derivatives originate from the IPR isomer C1-C100(382), although both C1-C100(344) and even nonclassical C1-C100(NC) can be also considered as the starting isomers.
Co-reporter:Sally Mabrouk, Ashish Dubey, Wenfeng Zhang, Nirmal Adhikari, Behzad Bahrami, Md Nazmul Hasan, Shangfeng Yang, and Qiquan Qiao
The Journal of Physical Chemistry C 2016 Volume 120(Issue 43) pp:24577-24582
Publication Date(Web):October 12, 2016
DOI:10.1021/acs.jpcc.6b06799
Perovskite solar cells offer tremendous potential for simple and low-cost solution-based fabrication with high power conversion efficiency. This work focused on adding an optimized amount of additive tetra-n-butylammonium triiodide (TBAI3) into the precursor PbI2 layer to improve the performance of perovskite solar cells. UV–vis absorption spectra exhibited an enhancement in the absorbance of perovskite films while AFM images showed smoother MAPbI3 film after adding TBAI3. X-ray diffraction (XRD) measurements indicated that TBAI3 acted as a polar Lewis base, forming an adduct with the Lewis acid Pb2+, increasing PbI2 solubility, and enhancing crystal growth of perovskite. Current density–voltage (J–V) characteristics and transient photocurrent measurements showed that the TBAI3 dopant achieved an increase in short circuit current density (Jsc) and open circuit voltage (Voc) and a decrease in the charge transport time compared to the reference cell without any additive. Perovskite solar cell efficiency was enhanced from 11.18% to 14.85% by adding TBAI3 dopant to the PbI2 precursor.
Co-reporter:Song Wang;Dr. Shangfeng Yang;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Chemistry - A European Journal 2016 Volume 22( Issue 15) pp:5138-5141
Publication Date(Web):
DOI:10.1002/chem.201504556
Abstract
High-temperature chlorination of pristine C98 fullerene isomers separated by HPLC from the fullerene soot afforded crystals of C98Cl22 and C98Cl20. An X-ray structure elucidation revealed, respectively, the presence of carbon cages of the most stable C2-C98(248) and rather unstable C1-C98(116), which represent the first isolated pentagon rule (IPR) isomers of fullerene C98 confirmed experimentally. The chlorination patterns of the chlorides are discussed in terms of the formation of isolated C=C bonds and aromatic substructures on the fullerene cages.
Co-reporter:Song Wang;Dr. Jing Huang;Congli Gao;Fei Jin;Dr. Qunxiang Li;Dr. Suyuan Xie;Dr. Shangfeng Yang
Chemistry - A European Journal 2016 Volume 22( Issue 24) pp:8309-8315
Publication Date(Web):
DOI:10.1002/chem.201600388
Abstract
Bingel–Hirsch reactions of trimetallic nitride clusterfullerenes (NCFs) generally yield methanofullerene (cyclopropane) adducts instead of singly bonded derivatives, which have been reported for monometallofullerenes. Herein, we report the synthesis and characterization of the Bingel–Hirsch derivative of a mixed metal nitride clusterfullerene (MMNCF) TiY2N@Ih-C80. Surprisingly, in contrast to the reported Bingel–Hirsch cyclopropane adducts of the analogous NCF Y3N@Ih-C80, the Bingel–Hirsch derivative of TiY2N@Ih-C80 is the first singly bonded monoadduct (labeled as TiY2N@C80-Mono) to be reported, which was determined unambiguously by single-crystal X-ray crystallography. Besides, the reactivity of TiY2N@Ih-C80 was found to be significantly improved relative to that of Y3N@Ih-C80. Upon substituting one endohedral yttrium (Y) atom of Y3N@Ih-C80 with titanium (Ti), the Bingel–Hirsch derivative changes from the cyclopropane to the singly bonded monoadduct, revealing that not only the reactivity but also the addition pattern of NCFs can be manipulated simultaneously through one endohedral metal atom substitution.
Co-reporter:Song Wang;Dr. Shangfeng Yang;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Chemistry – An Asian Journal 2016 Volume 11( Issue 1) pp:77-80
Publication Date(Web):
DOI:10.1002/asia.201501152
Abstract
High-temperature chlorination of three IPR isomers of fullerene C88, C2-C88(7), Cs-C88(17), and C2-C88(33), resulted in the isolation and X-ray structural characterization of C88(7)Cl12, C88(7)Cl24, C88(17)Cl22, and C88(33)Cl12/14. Chlorination patterns of C88(7) and C88(33) isomers are unusual in that one or more pentagons remain free from chlorination while some other pentagons are occupied by two or three Cl atoms. The addition patterns of the isolated chlorides are discussed in terms of the distribution of twelve pentagons on the carbon cages and the formation of stabilizing isolated C=C bonds and benzenoid rings.
Co-reporter:Song Wang;Dr. Shangfeng Yang;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Angewandte Chemie International Edition 2016 Volume 55( Issue 10) pp:3451-3454
Publication Date(Web):
DOI:10.1002/anie.201511928
Abstract
High-temperature chlorination of C100 fullerene followed by X-ray structure determination of the chloro derivatives enabled the identification of three isomers of C100 from the fullerene soot, specifically numbers 18, 425, and 417, which obey the isolated pentagon rule (IPR). Among them, isomers C1-C100(425) and C2-C100(18) afforded C1-C100(425)Cl22 and C2-C100(18)Cl28/30 compounds, respectively, which retain their IPR cage connectivities. In contrast, isomer C2v-C100(417) gives Cs-C100(417)Cl28 which undergoes a skeletal transformation by the loss of a C2 fragment, resulting in the formation of a nonclassical (NC) C1-C98(NC)Cl26 with a heptagon in the carbon cage. Most probably, two nonclassical C1-C100(NC)Cl18/22 chloro derivatives originate from the IPR isomer C1-C100(382), although both C1-C100(344) and even nonclassical C1-C100(NC) can be also considered as the starting isomers.
Co-reporter:Tao Wei; Song Wang; Xing Lu; Yuanzhi Tan; Jing Huang; Fupin Liu; Qunxiang Li; Suyuan Xie
Journal of the American Chemical Society 2015 Volume 138(Issue 1) pp:207-214
Publication Date(Web):December 8, 2015
DOI:10.1021/jacs.5b10115
So far the entrapped metals for the isolated endohedral metallofullerenes (EMFs) are primarily limited to rare earth metals, whereas except group-IVB metals, whether it is possible to entrap other d-block transition metals remains unclear. Herein we report the successful entrapment of the group-VB transition metal vanadium(V) into fullerene cage, affording the heretofore unknown V-containing EMFs. Two novel V-containing EMFs—VxSc3–xN@C80 (x = 1, 2)—were isolated, and their molecular structures were unambiguously determined by X-ray crystallography to be Ih(7)-C80 cage entrapping the planar VSc2N/V2ScN clusters. VxSc3–xN@Ih(7)-C80 (x = 1, 2) were further characterized by UV–vis–NIR and ESR spectroscopies and electrochemistry, revealing that the electronic and magnetic properties of VxSc3–xN@Ih(7)-C80 (x = 1, 2) are tunable upon varying the number of entrapped V atoms (i.e., x value). The molecular structures and electronic properties of VxSc3–xN@Ih(7)-C80 (x = 1, 2) were further compared with those of the reported analogous EMFs based on lanthanide metals and the adjacent group-IVB transition metal Ti, revealing the peculiarity of the group-VB transition metal V-based EMFs.
Co-reporter:Tao Wei; Song Wang; Fupin Liu; Yuanzhi Tan; Xianjun Zhu; Suyuan Xie
Journal of the American Chemical Society 2015 Volume 137(Issue 8) pp:3119-3123
Publication Date(Web):February 7, 2015
DOI:10.1021/jacs.5b00199
The long-sought small-bandgap endohedral fullerene Sc3N@C82 with low kinetic stability has been successfully synthesized and isolated for the first time, for which the molecular structure has been unambiguously determined as Sc3N@C82-C2v(39718) by single crystal X-ray diffraction. The C82-C2v(39718) (or labeled as C82-C2v(9) according to the conventional numbering of the isolated pentagon rule (IPR) isomers based on the Fowler–Monolopoulos spiral algorithm) isomeric cage of Sc3N@C82 agrees well with its most stable isomer previously predicted by DFT computations and is dramatically different to those of the reported counterparts M3N@C82–Cs(39663) (M = Gd, Y) based on a non-IPR C82 isomer, revealing the strong dependence of the cage isomeric structure on the size of the encaged metal for C82-based metal nitride clusterfullerenes (NCFs).
Co-reporter:Jian Guan, Xiang Chen, Tao Wei, Fupin Liu, Song Wang, Qing Yang, Yalin Lu and Shangfeng Yang
Journal of Materials Chemistry A 2015 vol. 3(Issue 8) pp:4139-4146
Publication Date(Web):24 Nov 2014
DOI:10.1039/C4TA05456C
Using a facile solid-state mechanochemical method by ball milling, we successfully synthesized the first directly bonded graphene–C60 hybrid, for which LiOH is found to play a crucial role as the catalyst. The hybrid structure of graphene–C60 is confirmed by FTIR, Raman, XRD and XPS characterizations, and its conformation is proposed, featuring the direct bonding of graphene nanoplatelets and C60via two C–C single bonds. SEM measurement suggests that severe edge distortions occur for graphene–C60 hybrid, and HR-TEM study indicate the covalent attaching of C60 molecules onto the edge of graphene nanoplatelets. The graphene–C60 hybrid is applied as a carbon-based electrocatalyst toward oxygen reduction reaction (ORR), showing improved ORR electrocatalytic activity than the pristine graphite.
Co-reporter:Zhiqiang Zhao, Qiliang Wu, Fei Xia, Xiang Chen, Yawei Liu, Wenfeng Zhang, Jun Zhu, Songyuan Dai, and Shangfeng Yang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 3) pp:1439
Publication Date(Web):December 23, 2014
DOI:10.1021/am505387q
Copper(II) bromide (CuBr2) salt has been applied to dope poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the hole transport layer (HTL) in polymer solar cells (PSCs), improving dramatically the conductivity of PEDOT:PSS film and consequently the device power conversion efficiency (PCE). Under the optimized doping concentration of CuBr2 of 10 mmol·L–1, PCE of the CuBr2:PEDOT:PSS HTL-incorporated BHJ-PSC device based on poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5- (4′,7′-di-2-thienyl-2′,1′,3′- benzothiadiazole) (PCDTBT) and [6,6]-phenyl C71-butyric acid methyl ester (PC71BM) (PCDTBT:PC71BM) reaches 7.05%, which is improved by ∼20.7% compared to that of the reference device based on pristine PEDOT:PSS HTL (5.84%) and represents the highest PCE for PCDTBT:PC71BM-based PSC devices without an electron transport layer (ETL) reported so far. The dramatic improvement of the conductivity of PEDOT:PSS film is interpreted by the weakening of the Coulombic attractions between PEDOT and PSS components. The work function of CuBr2:PEDOT:PSS slightly increases compared to that of the undoped PEDOT:PSS as inferred from scanning Kelvin probe microscopy (SKPM) measurements, contributing to the improved PCE due to the increases of the open-current voltage (Voc) and fill factor (FF).Keywords: conductivity; copper bromide; hole transport layer; PEDOT:PSS; polymer solar cells
Co-reporter:Qiliang Wu, Cong Xue, Yi Li, Pengcheng Zhou, Weifeng Liu, Jun Zhu, Songyuan Dai, Changfei Zhu, and Shangfeng Yang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 51) pp:28466
Publication Date(Web):December 8, 2015
DOI:10.1021/acsami.5b09572
Kesterite-structured quaternary semiconductor Cu2ZnSnS4 (CZTS) has been commonly used as light absorber in thin film solar cells on the basis of its optimal bandgap of 1.5 eV, high absorption coefficient, and earth-abundant elemental constituents. Herein we applied CZTS nanoparticles as a novel inorganic hole transporting material (HTM) for organo-lead halide perovskite solar cells (PSCs) for the first time, achieving a power conversion efficiency (PCE) of 12.75%, which is the highest PCE for PSCs with Cu-based inorganic HTMs reported up to now, and quite comparable to that obtained for PSCs based on commonly used organic HTM such as 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-MeOTAD). The size of CZTS nanoparticles and its incorporation condition as HTM were optimized, and the effects of CZTS HTM on the optical absorption, crystallinity, morphology of the perovskite film and the interface between the perovskite layer and the Au electrode were investigated and compared with the case of spiro-MeOTAD HTM, revealing the role of CZTS in efficient hole transporting from the perovskite layer to the top Au electrode as confirmed by the prohibited charge recombination at the perovskite/Au electrode interface. On the basis of the effectiveness of CZTS as a low-cost HTM competitive to spiro-MeOTAD in PSCs, we demonstrate the new role of CZTS in photovoltaics as a hole conductor beyond the traditional light absorber.Keywords: CZTS; hole-transport material; interface; light absorber; perovskite solar cells
Co-reporter:Fei Xia, Qiliang Wu, Pengcheng Zhou, Yi Li, Xiang Chen, Qing Liu, Jun Zhu, Songyuan Dai, Yalin Lu, and Shangfeng Yang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 24) pp:13659
Publication Date(Web):June 8, 2015
DOI:10.1021/acsami.5b03525
An amphiphilic surfactant, oleamide, was applied to dope the PCBM electron transport layer (ETL) of inverted structure perovskite solar cells (ISPSCs), resulting in a dramatic efficiency enhancement. Under the optimized oleamide doping ratio of 5.0 wt %, the power conversion efficiency of the CH3NH3PbIxCl3-x perovskite-based ISPSC device is enhanced from 10.05% to 12.69%, and this is primarily due to the increases of both fill factor and short-circuit current. According to the surface morphology study of the perovskite/PCBM bilayer film, oleamide doping improves the coverage of PCBM ETL onto the perovskite layer, and this is beneficial for the interfacial contact between the perovskite layer and the Ag cathode and consequently the electron transport from perovskite to the Ag cathode. Such an improved electron transport induced by oleamide doping is further evidenced by the impedance spectroscopic study, revealing the prohibited electron–hole recombination at the interface between the perovskite layer and the Ag cathode.Keywords: electron transport layer; interface; oleamide; PCBM; perovskite solar cells;
Co-reporter:Zhiqiang Zhao, Xiang Chen, Qing Liu, Qiliang Wu, Jun Zhu, Songyuan Dai, Shangfeng Yang
Organic Electronics 2015 Volume 27() pp:232-239
Publication Date(Web):December 2015
DOI:10.1016/j.orgel.2015.09.022
•A novel zwitterion (MOPSO) was applied to dope PEDOT:PSS for the first time.•The conductivity of PEDOT:PSS film upon MOPSO doping was improved by about 100-folds.•The PCE of the MOPSO:PEDOT:PSS HTL-based PTB7:PC71BM BHJ-PSC devices reaches 7.56%.•The improved PCE upon MOPSO doping is mainly due to the increase of Jsc.Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was doped by a novel zwitterion, 3-(N-morpholino)-2-hydroxypropanesulfonic acid (MOPSO), leading to a dramatic improvement of its conductivity and consequently efficiency enhancement in polymer solar cells (PSCs) based on PEDOT:PSS hole transport layer (HTL) and versatile photoactive systems. Under the optimized MOPSO doping concentration of 20 mmol l−1, the conductivity of PEDOT:PSS film increased by about two orders of magnitude, and this is interpreted by the weakening of the Coulombic attractions between PEDOT and PSS components induced by MOPSO. MOPSO doped PEDOT:PSS was applied as HTL of bulk heterojunction (BHJ) PSC devices based on different photoactive layers including poly(3-hexylthiophene-2,5-diyl) (P3HT)/[6,6]-phenyl C61-butyric acid methyl ester (PC61BM), poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole) (PCDTBT)/[6,6]-phenyl C71-butyric acid methyl ester (PCDTBT:PC71BM) and thieno[3,4-b]-thiophene/benzodithiophene (PTB7):PC71BM, leading to the best power conversion efficiency (PCE) of 3.62%, 7.03% and 7.56%, respectively, which are obviously enhanced relative to those of the corresponding reference devices based on pristine PEDOT:PSS HTL. The efficiency enhancement upon MOPSO doping is found to result from the increase of short-circuit current density (Jsc), which is attributed to the increase of the photoabsorption of the photoactive layer and the improved conductivity of PEDOT:PSS HTL.A novel zwitterion, 3-(N-morpholino)-2-hydroxypropanesulfonic acid (MOPSO), was applied to dope PEDOT:PSS, leading to a dramatic increase of the conductivity of PEDOT:PSS film. MOPSO:PEDOT:PSS was incorporated as hole transport layer (HTL) in BHJ-PSC devices based on P3HT:PC61BM, PCDTBT:PC71BM and PTB7:PC71BM, resulting in obvious efficiency enhancements due to the increase of Jsc, which is attributed to the conjunct factors including the increase of the photoabsorption of the photoactive layer and the improved conductivity of PEDOT:PSS HTL.
Co-reporter:Tao Wei;Dr. Shangfeng Yang;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Chemistry – An Asian Journal 2015 Volume 10( Issue 3) pp:559-562
Publication Date(Web):
DOI:10.1002/asia.201500041
Abstract
High-temperature chlorination of a fullerene C86 with VCl4 afforded non-classical C84Cl30 and C82Cl30 containing one and two heptagons, respectively, in the carbon cages. Two types of C2 losses, which differ in the final arrangements of separate or fused pentagons, can occur successively in either order, producing rather flat or concave regions on the shrinked carbon cage. In the chlorination-promoted skeletal transformation of C86 (isomer no. 16) with the loss(es) of C2 units, the structures of the starting, intermediate, and final compounds were all revealed unambiguously by X-ray single crystal diffraction.
Co-reporter:Dr. Ilya N. Ioffe;Dr. Shangfeng Yang;Song Wang;Dr. Erhard Kemnitz;Dr. Lev N. Sidorov;Dr. Sergey I. Troyanov
Chemistry - A European Journal 2015 Volume 21( Issue 13) pp:4904-4907
Publication Date(Web):
DOI:10.1002/chem.201406487
Abstract
Chlorination of the C100(18) fullerene with a mixture of VCl4 and SbCl5 gives rise to branched skeletal transformations affording non-classical (NC) C94(NC1)Cl22 with one heptagon in the carbon cage together with the previously reported C96(NC3)Cl20 with three heptagons. The three-step pathway to C94(NC1)Cl22 starts with two successive C2 losses of 5:6 CC bonds to give two cage heptagons, whereas the third C2 loss of the 5:5 CC bond from a pentalene fragment eliminates one of the heptagons. Quantum-chemical calculations demonstrate that the two unusual skeletal transformations—creation of a heptagon in C96(NC3)Cl20 through a Stone–Wales rearrangement and the presently reported elimination of a heptagon through C2 loss—are both characterized by relatively low activation energy.
Co-reporter:Dr. Shangfeng Yang;Dr. Tao Wei;Dr. Kerstin Scheurell;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Chemistry - A European Journal 2015 Volume 21( Issue 43) pp:15138-15141
Publication Date(Web):
DOI:10.1002/chem.201501549
Abstract
High-temperature chlorination of fullerene C88 (isomer 33) with VCl4 gives rise to skeletal transformations affording several nonclassical (NC) fullerene chlorides, C86(NC1)Cl24/26 and C84(NC2)Cl26, with one and two heptagons, respectively, in the carbon cages. The branched skeletal transformation including C2 losses as well as a Stone–Wales rearrangement has been comprehensively characterized by the structure determination of two intermediates and three final chlorination products. Quantum-chemical calculations demonstrate that the average energy of the CCl bond is significantly increased in chlorides of nonclassical fullerenes with a large number of chlorinated sites of pentagon–pentagon adjacency.
Co-reporter:Ying Xu, Xiang Chen, Fupin Liu, Xi Chen, Jianhe Guo and Shangfeng Yang
Materials Horizons 2014 vol. 1(Issue 4) pp:411-418
Publication Date(Web):24 Apr 2014
DOI:10.1039/C4MH00037D
Three-dimensional (3D) nanostructures of an endohedral fullerene, Sc3N@C80 (Ih), including both cubic-shaped and unprecedented dice-shaped crystals, have been successfully prepared for the first time via a modified liquid–liquid interfacial precipitation (LLIP) method integrating ultrasonication. By simply switching ultrasonication on/off upon mixing the good/poor (mesitylene/isopropanol) solvents, the dice- and cubic-shaped Sc3N@C80 crystals have been selectively prepared, and their size can be readily controlled by varying the concentration of the starting Sc3N@C80 solution in mesitylene. The growth mechanism of the cubic- and dice-shaped Sc3N@C80 crystals has been proposed, highlighting the formation of local mesitylene cavities which lead to the nucleation and growth of Sc3N@C80 molecules, while the formation of the dice structure. i.e., a hole in each facet of the cube, was primarily due to the hindered diffusion of Sc3N@C80 solutes by ultrasonication-generated gas microbubbles. The crystal structure of the Sc3N@C80 cubes has been determined as a simple cubic unit cell with a lattice constant of a = 10.8 Å. Finally the dice-shaped Sc3N@C80 crystals were applied as a Pt catalyst support for the methanol oxidation reaction (MOR), revealing the improved MOR activity compared to the cubic-shaped Sc3N@C80 crystals due to its larger surface area resulting from the dice (hole) structure.
Co-reporter:Xuemei Zhao, Chenhui Xu, Haitao Wang, Fei Chen, Wenfeng Zhang, Zhiqiang Zhao, Liwei Chen, and Shangfeng Yang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 6) pp:4329
Publication Date(Web):February 27, 2014
DOI:10.1021/am500013s
Three amino-containing small-molecule organic materials—biuret, dicyandiamide (DCDA), and urea—were successfully applied as novel cathode buffer layers (CBLs) in P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs) for the first time, resulting in obvious efficiency enhancement. Under the optimized condition, the power conversion efficiencies (PCEs) of the CBL-incorporated BHJ-PSC devices are 3.84%, 4.25%, and 4.39% for biuret, DCDA, and urea, which are enhanced by ∼15%, ∼27%, and ∼31%, respectively, compared to the reference poly(3-hexylthiophene-2,5-diyl) : [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) BHJ-PSC device without any CBL. The efficiency enhancement is primarily attributed to the increases of both short-circuit current density (Jsc) and fill factor (FF), for which the enhancement ratio is found to be sensitively dependent on the molecular structure of small-molecule organic materials. The surface morphologies and surface potential changes of the CBL-incorporated P3HT:PCBM photoactive layers were studied by atomic force microscopy and scanning Kelvin probe microscopy, respectively, suggesting the formation of an interfacial dipole layer between the photoactive layer and Al cathode, which may decrease the energy level offset between the work function of Al and the lowest unoccipoed molecular orbital level (LUMO) of the PCBM acceptor and consequently facilitate electron extraction by the Al cathode. The difference in the enhancement effect of biuret, DCDA, and urea is due to their difference on the work function matching with P3HT:PCBM. Besides, the coordination interaction between the lone-pair electrons on the N atoms of the amino (−NH2) group and the Al atoms may prohibit interaction between Al and the thiophene rings of P3HT, contributing to the efficiency enhancement of the CBL-incorporated devices as well. In this sense, the different CBL performance of biuret, DCDA, and urea is also proposed to partially originate from the differences on their chemical structure, specifically the number of amino groups.Keywords: amino group; biuret; cathode buffer layer; dicyandiamide; polymer solar cells; urea;
Co-reporter:Fupin Liu, Song Wang, Jian Guan, Tao Wei, Minxiang Zeng, and Shangfeng Yang
Inorganic Chemistry 2014 Volume 53(Issue 10) pp:5201-5205
Publication Date(Web):May 1, 2014
DOI:10.1021/ic500353k
The first terbium (Tb)-monometallic cyanide clusterfullerene (CYCF), TbCN@C82, has been successfully synthesized and isolated, whose molecular structure was determined unambiguously as TbCN@C2(5)-C82 by single crystal X-ray diffraction. The C2(5)-C82 isomeric cage represents a new cage capable of encapsulating a monometallic cyanide cluster. The C–N bond length within the encaged TbCN cluster is determined to be 0.94(5) Å, which is smaller by at least 0.17 Å than those of the reported C–N triplet bonds in traditional cyanide/nitrile compounds and cyano coordination complexes. An electronic configuration of [Tb3+(CN)−]2+@[C82]2– was proposed for TbCN@C82.
Co-reporter:Wenfeng Zhang, Xianghong Bi, Xuemei Zhao, Zhiqiang Zhao, Jun Zhu, Songyuan Dai, Yalin Lu, Shangfeng Yang
Organic Electronics 2014 Volume 15(Issue 12) pp:3445-3451
Publication Date(Web):December 2014
DOI:10.1016/j.orgel.2014.09.026
•Isopropanol (IPA)-treated PEDOT:PSS was incorporated as a new ETL in BHJ-PSC device.•The electron transport property of IPA-treated PEDOT:PSS was revealed.•PCE of ETL-incorporated device is quite comparable to that of the reference device.•An annealing treatment of IPA-treated PEDOT:PSS ETL led to an increase of PCE.Isopropanol (IPA)-treated poly(3,4-ethylenedioxithiophene):poly(styrene sulfonate) (PEDOT:PSS) was applied as a new electron transport layer (ETL) in P3HT:PCBM bulk heterojunction polymer solar cell (BHJ-PSC) devices for the first time, revealing the electron transport property of IPA-treated PEDOT:PSS in sharp contrast to the well known hole transport property of the untreated PEDOT:PSS. Under the optimized condition for incorporating PEDOT:PSS ETL, the power conversion efficiency (PCE) of the ITO/untreated PEDOT:PSS (HTL)/P3HT:PCBM/IPA-treated PEDOT:PSS (ETL)/Al device (3.09%) is quite comparable to that of the reference ITO/untreated PEDOT:PSS (HTL)/P3HT:PCBM/Al device without any ETL (3.06%), and an annealing treatment of PEDOT:PSS ETL at 120 °C for 10 min led to a PCE of 3.25%, which even slightly surpasses that of the reference device, revealing the electron transport property of IPA-treated PEDOT:PSS. The electron transport property of IPA-treated PEDOT:PSS is interpreted by the lowering of the work function of PEDOT:PSS upon IPA treatment and incorporation as ETL as probed by scanning Kelvin probe microscopy (SKPM).By incorporating isopropanol (IPA)-treated poly(3,4-ethylenedioxithiophene):poly(styrene sulfonate) (PEDOT:PSS) as a new electron transport layer (ETL) in P3HT:PCBM bulk heterojunction polymer solar cell (BHJ-PSC) devices, we revealed the electron transport property of IPA-treated PEDOT:PSS for the first time. The electron transport property of IPA-treated PEDOT:PSS is interpreted by the lowering of the work function of PEDOT:PSS upon IPA treatment and incorporation as ETL.
Co-reporter:Minghua Li, Zhixiong Liu, Juling Ruan, Xiang Chen, Fangda Xu, Xia Chen, Xing Lu and Shangfeng Yang
RSC Advances 2014 vol. 4(Issue 96) pp:53999-54006
Publication Date(Web):10 Oct 2014
DOI:10.1039/C4RA11305E
Sulfonic acid was successfully grafted onto graphene oxide (GO) via a facile noncovalent functionalization approach using pyrene as the anchoring bridge, affording a novel water-processable sulfonic acid functionalized GO, which shows improved hole transport in polymer solar cells (PSCs) compared to that of pristine GO. The successful grafting of 1-pyrenesulfonic acid (PSA) onto the carbon basal plane of GO is confirmed by FT-IR, UV-vis and Raman spectroscopic studies. An AFM study on the film morphology of GO–PSA reveals that the PSA moiety attaches onto both sides of the single layered graphene sheets, thus prohibiting the exfoliated single-layer graphene sheets from re-stacking. Finally, GO–PSA was applied as an effective hole transport layer (HTL) in poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction (BHJ) PSC devices. Under the optimized conditions, the ITO/GO–PSA/P3HT:PCBM/Al BHJ-PSC device has a power conversion efficiency (PCE) of 2.86%, which is enhanced by ca. 42.3% compared to that of the reference device based on pristine GO HTL (2.01%). The PCE enhancement is primarily attributed to the increase of fill factor (FF) due to the improved hole transport of GO upon PSA grafting, which results from the improved conductivity of GO upon PSA grafting and the decrease of the contact resistance between P3HT and GO because of the enhanced surface doping of P3HT by the –OSO3H groups.
Co-reporter:Jingzhe Li, Fantai Kong, Guohua Wu, Wangchao Chen, Fuling Guo, Bing Zhang, Jianxi Yao, Shangfeng Yang, Songyuan Dai, Xu Pan
Synthetic Metals 2014 Volume 197() pp:188-193
Publication Date(Web):November 2014
DOI:10.1016/j.synthmet.2014.09.023
•Di-n-alkylphosphinic acids were used as coadsorbents with indoline sensitizer D149.•We examine the effect of the different alkyl chains on DSCs performance.•The device performance was obviously enhanced with increasing the alkyl chain length.•The device efficiency was increased by about 10% with DHdPA co-adsorbed.Three di-n-alkylphosphinic acids (DPAs) with different chain lengths (1, 8, 16) were adopted as coadsorbents in dye-sensitized solar cells (DSCs) with organic sensitizer D149. The adsorption behavior of these coadsorbents on nanoporous TiO2 surface through POTi bond was confirmed by FT-IR spectra. And the performance of all devices was detected on the basis of photocurrent–voltage (J–V) characteristics and electrochemical impedance spectroscopy (EIS). It was found that the amount of dye adsorption gradually decreased with increasing alkyl chain length of DPAs, which was contributed to the competitive adsorption between dye D149 and coadsorbents. In spite of this, di-n-hexadecylphosphinic acid (DHdPA) performed best both in the improvement of short-circuit current density (Jsc) and open-circuit voltage (Voc). The increase of open-circuit photovoltage was ascribed to the negative movement of the conduction band edge and the retardation of electron recombination. Although the dye adsorption amount reduced to a great degree, the break up of dye aggregation mainly contribute to the enhancement of short-circuit current density. The overall conversion efficiency was further improved from 5.53% to 6.09% with DHdPA as the coadsorbent for D149 based device.
Co-reporter:Dr. Shangfeng Yang;Tao Wei;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Chemistry – An Asian Journal 2014 Volume 9( Issue 1) pp:79-82
Publication Date(Web):
DOI:10.1002/asia.201301230
Abstract
Isolation and characterization of very large fullerenes is hampered by a drastic decrease of their content in fullerene soot with increasing fullerene size and a simultaneous increase of the number of possible IPR (Isolated Pentagon Rule) isomers. In the present work, fractions containing mixtures of C102 and C104 were isolated in very small quantities (several dozens of micrograms) by multi-step recycling HPLC from an arc-discharge fullerene soot. Two such fractions were used for chlorination with a VCl4/SbCl5 mixture in glass ampoules at 350–360 °C. The resulting chlorides were investigated by single-crystal X-ray diffraction using synchrotron radiation. By this means, two IPR isomers of C104, numbers 258 and 812 (of 823 topologically possible isomers), have been confirmed for the first time as chlorides, C1-C104(258)Cl16 and D2-C104(812)Cl24, respectively, while an admixture of C2-C104(811)Cl24 was assumed to be present in the latter chloride. DFT calculations showed that pristine C104(812) belongs to rather stable C104 cages, whereas C104(258) is much less stable.
Co-reporter:Dr. Shangfeng Yang;Tao Wei;Song Wang;Dr. Ilya N. Ioffe;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Chemistry – An Asian Journal 2014 Volume 9( Issue 11) pp:3102-3105
Publication Date(Web):
DOI:10.1002/asia.201402859
Abstract
Chlorination of various HPLC fractions of C96 with a mixture of VCl4 and SbCl5 at 340–360 °C and single-crystal X-ray diffraction study of the products led to the identification of three new IPR isomers of C96. The C96(175) isomer forms a stable chloride, C96(175)Cl20, while chlorides of two other new isomers, C96(114) and C96(80), undergo cage shrinkage yielding C94(NC1)Cl28 and C96(NC2)Cl32 with non-classical (NC) cages. These two NC chlorides contain, respectively, one and two heptagons flanked by pairs of fused pentagons and are stabilized by chlorine attachment to the emerging pentagon–pentagon junctions. Thus, the number of the experimentally confirmed C96 isomers has reached nine, which corroborates the empirical rule that the C6n fullerenes exhibit particularly rich isomerism.
Co-reporter:Dr. Shangfeng Yang;Song Wang;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Angewandte Chemie 2014 Volume 126( Issue 9) pp:2492-2495
Publication Date(Web):
DOI:10.1002/ange.201310099
Abstract
Chlorination of C100 fullerene with a mixture of VCl4 and SbCl5 afforded C96Cl20 with a strongly unconventional structure. In contrast to the classical fullerenes containing only hexagonal and pentagonal rings, the C96 cage contains three heptagonal rings and, therefore, should be classified as a fullerene with a nonclassical cage (NCC). There are several types of pentagon fusions in the C96 cage including pentagon pairs and pentagon triples. The three-step pathway from isolated-pentagon-rule (IPR) C100 to C96(NCC-3hp) includes two C2 losses, which create two cage heptagons, and one Stone–Wales rotation under formation of the third heptagon. Structural reconstruction established C100 isomer no. 18 from 450 topologically possible IPR isomers as the starting C100 fullerene. Until now, no pristine C100 isomers have been confirmed based on the experimental results.
Co-reporter:Dr. Shangfeng Yang;Song Wang;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Angewandte Chemie International Edition 2014 Volume 53( Issue 9) pp:2460-2463
Publication Date(Web):
DOI:10.1002/anie.201310099
Abstract
Chlorination of C100 fullerene with a mixture of VCl4 and SbCl5 afforded C96Cl20 with a strongly unconventional structure. In contrast to the classical fullerenes containing only hexagonal and pentagonal rings, the C96 cage contains three heptagonal rings and, therefore, should be classified as a fullerene with a nonclassical cage (NCC). There are several types of pentagon fusions in the C96 cage including pentagon pairs and pentagon triples. The three-step pathway from isolated-pentagon-rule (IPR) C100 to C96(NCC-3hp) includes two C2 losses, which create two cage heptagons, and one Stone–Wales rotation under formation of the third heptagon. Structural reconstruction established C100 isomer no. 18 from 450 topologically possible IPR isomers as the starting C100 fullerene. Until now, no pristine C100 isomers have been confirmed based on the experimental results.
Co-reporter:Dr. Shangfeng Yang;Song Wang;Dr. Sergey I. Troyanov
Chemistry - A European Journal 2014 Volume 20( Issue 23) pp:6875-6878
Publication Date(Web):
DOI:10.1002/chem.201402028
Abstract
The chlorination of HPLC fractions with pristine giant fullerenes, C102 and C104, followed by X-ray crystallographic study of chlorides, C102(603)Cl18/20 and C104(234)Cl16–22, confirmed the presence of the most stable IPR (IPR=Isolated Pentagon Rule) isomers, C102(603) and C104(234), in the fullerene soot. The discussion concerns the chlorination patterns of polychlorides and relative stability of pristine isomers of C102 and C104 fullerenes.
Co-reporter:Tao Wei;Dr. Nadezhda B. Tamm;Dr. Shangfeng Yang;Dr. Sergey I. Troyanov
Chemistry – An Asian Journal 2014 Volume 9( Issue 9) pp:2449-2452
Publication Date(Web):
DOI:10.1002/asia.201402573
Abstract
Trifluoromethylated derivatives of Sc3N@Ih-C80 and Sc3N@D5h-C80 were synthesized by the reaction with CF3I at 440 °C. HPLC separation of the mixture of Sc3N@D5h-C80(CF3)n derivatives resulted in isolation and X-ray structure determination of Sc3N@D5h-C80(CF3)16, which represents a precursor of the known Sc3N@D5h-C80(CF3)18. Among the CF3 derivatives of Sc3N@Ih-C80, two new isomers of Sc3N@Ih-C80(CF3)14 (Sc-14-VI and Sc-14-VII) were isolated by HPLC, and their molecular structures were determined by X-ray diffraction, thus enabling a comprehensive comparison of altogether seven isomers. Two types of addition patterns with different orientations of the Sc3N cluster relative to the Ih-C80 fullerene cage were established. In particular, Sc-14-VII represents a direct precursor of the known Sc3N@Ih-C80(CF3)16-II. All molecular structures exhibit an ordered position of a Sc3N cluster inside the fullerene C80 cage.
Co-reporter:Alexey A. Popov, Shangfeng Yang, and Lothar Dunsch
Chemical Reviews 2013 Volume 113(Issue 8) pp:5989
Publication Date(Web):May 2, 2013
DOI:10.1021/cr300297r
Co-reporter:Ying Xu, Jianhe Guo, Tao Wei, Xi Chen, Qing Yang and Shangfeng Yang
Nanoscale 2013 vol. 5(Issue 5) pp:1993-2001
Publication Date(Web):03 Jan 2013
DOI:10.1039/C2NR33586G
Micron-sized hexagonal single-crystalline Sc3N@C80 rods have been successfully prepared for the first time by a liquid–liquid interfacial precipitation (LLIP) method with the first utilization of p-xylene as the solvent dissolving Sc3N@C80. The effect of the concentration of the Sc3N@C80 solution on the size and length of the Sc3N@C80 rods has been studied, indicating that the length of Sc3N@C80 rods can be readily controlled by varying the concentration of the Sc3N@C80 solution. The crystal structure of the Sc3N@C80 rods has been investigated by XRD and the electron diffraction patterns, pointing to a hexagonal system. The growth kinetics of the Sc3N@C80 rods has been studied by monitoring the morphology evolution of the Sc3N@C80 crystals, and a plausible mechanism is proposed, featuring an intermediate hexagonal star-shaped prism structure with grooves. Raman spectroscopic characterization confirmed that the Sc3N@C80 rods are composed of monomeric pristine Sc3N@C80 molecules and no polymerization has occurred in the crystal lattice, and a significant Raman enhancement in the low-energy region is observed. According to the UV-vis-NIR absorption spectroscopic study of the Sc3N@C80 rods, where much broader and stronger absorptions in the visible and near-infrared regions than that of the Sc3N@C80 solution were revealed, we conclude that the electronic structure of the Sc3N@C80 molecule is largely perturbed upon formation of micron-sized single-crystalline rods because of the strong intermolecular π–π interactions. Finally photoelectrochemical application of the Sc3N@C80 rods was studied based on a Sc3N@C80 rods-modified ITO electrode prepared by electrophoretic deposition and revealed a higher photocurrent response than that obtained in the Sc3N@C80 films drop-coated onto an ITO electrode.
Co-reporter:Shangfeng Yang, Chuanbao Chen, Xiaofang Li, Tao Wei, Fupin Liu and Song Wang
Chemical Communications 2013 vol. 49(Issue 92) pp:10844-10846
Publication Date(Web):30 Sep 2013
DOI:10.1039/C3CC46277C
The first Bingel–Hirsch reaction of TiSc2N@Ih-C80 afforded two unconventional singly bonded monoadducts, revealing the dramatically improved reactivity compared to Sc3N@Ih-C80 and obvious change in the addition pattern.
Co-reporter:Shangfeng Yang, Tao Wei, Song Wang, Daria V. Ignat'eva, Erhard Kemnitz and Sergey I. Troyanov
Chemical Communications 2013 vol. 49(Issue 72) pp:7944-7946
Publication Date(Web):11 Jul 2013
DOI:10.1039/C3CC44386H
The chlorination of a pristine C102 fullerene separated by HPLC from fullerene soot afforded crystals of C102Cl20 with a non-IPR (IPR = isolated pentagon rule) cage containing two pairs of fused pentagons; structural reconstruction of a two-step Stone–Wales rearrangement revealed the starting IPR isomer (no. 19) of C102.
Co-reporter:Haitao Wang, Wenfeng Zhang, Chenhui Xu, Xianghong Bi, Boxue Chen, and Shangfeng Yang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 1) pp:26
Publication Date(Web):December 12, 2012
DOI:10.1021/am302317v
A non-conjugated polymer poly(vinylpyrrolidone) (PVP) was applied as a new cathode buffer layer in P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs), by means of either spin coating or self-assembly, resulting in significant efficiency enhancement. For the case of incorporation of PVP by spin coating, power conversion efficiency (PCE) of the ITO/PEDOT:PSS/P3HT:PCBM/PVP/Al BHJ-PSC device (3.90%) is enhanced by 29% under the optimum PVP spin-coating speed of 3000 rpm, which leads to the optimum thickness of PVP layer of ∼3 nm. Such an efficiency enhancement is found to be primarily due to the increase of the short-circuit current (Jsc) (31% enhancement), suggesting that the charge collection increases upon the incorporation of a PVP cathode buffer layer, which originates from the conjunct effects of the formation of a dipole layer between P3HT:PCBM active layer and Al electrodes, the chemical reactions of PVP molecules with Al atoms, and the increase of the roughness of the top Al film. Incorporation of PVP layer by doping PVP directly into the P3HT:PCBM active layer leads to an enhancement of PCE by 13% under the optimum PVP doping ratio of 3%, and this is interpreted by the migration of PVP molecules to the surface of the active layer via self-assembly, resulting in the formation of the PVP cathode buffer layer. While the formation of the PVP cathode buffer layer is fulfilled by both fabrication methods (spin coating and self-assembly), the dependence of the enhancement of the device performance on the thickness of the PVP cathode buffer layer formed by self-assembly or spin coating is different, because of the different aggregation microstructures of the PVP interlayer.Keywords: cathode buffer layer; poly(vinylpyrrolidone); polymer solar cells; power conversion efficiency; self-assembly; spin coating;
Co-reporter:Muqing Chen, Minghua Li, Haitao Wang, Shuxuan Qu, Xuemei Zhao, Lixin Xie and Shangfeng Yang
Polymer Chemistry 2013 vol. 4(Issue 3) pp:550-557
Publication Date(Web):13 Sep 2012
DOI:10.1039/C2PY20651J
A novel double cable donor–acceptor poly(3-hexylthiophene) (P3HT) derivative (PCBM-Ph-P3HT) was successfully synthesized via a facile postpolymerization approach followed by a Steglich esterification reaction, which was doped in a P3HT:PCBM (PCBM = [6,6]-phenyl-C61-butyric acid methyl ester) blend solution so as to study its effect on the device performance of P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs). The successful attachment of PCBM as the side chain onto the P3HT backbone via a phenyl group is confirmed by both 1H NMR and UV-Vis spectroscopic studies. The fluorescence intensity of PCBM-Ph-P3HT in chlorobenzene shows ∼63% quenching of the fluorescence of P3HT, indicating a strong intramolecular photoinduced electron transfer between P3HT and PCBM moieties. PCBM-Ph-P3HT was doped into P3HT:PCBM blend solution with different doping ratios (1, 2 and 5 wt%) and the surface morphology of PCBM-Ph-P3HT-doped film was studied by AFM, indicating that PCBM-Ph-P3HT promotes the bicontinuous interpenetrating networks of the P3HT and PCBM components due to its amphiphilicity toward P3HT and PCBM like a “surfactant”. At the optimum PCBM-Ph-P3HT doping ratio of 1 wt%, the P3HT:PCBM BHJ-PSC devices doped by PCBM-Ph-P3HT show an enhanced power conversion efficiency (PCE), with the maximum PCE being 3.40% which has ca. 12% enhancement compared to that of the reference P3HT:PCBM device. The enhancement of PCE is evidently attributed to the increase of short-circuit current (Jsc), and proposed enhancement mechanism is that the improvement on the bicontinuous interpenetrating networks of the P3HT and PCBM components upon PCBM-Ph-P3HT doping leads to the increase of the charge carrier mobility.
Co-reporter:Fupin Liu, Jian Guan, Tao Wei, Song Wang, Mingzhi Jiao, and Shangfeng Yang
Inorganic Chemistry 2013 Volume 52(Issue 7) pp:3814-3822
Publication Date(Web):March 12, 2013
DOI:10.1021/ic302436k
A series of nitrogen-containing inorganic solid compounds with variable oxidation states of nitrogen and counter ions have been successfully applied as new inorganic solid nitrogen sources toward the synthesis of Sc-based metal nitride clusterfullerenes (Sc-NCFs), including ammonium salts [(NH4)xH3-xPO4 (x = 0–2), (NH4)2SO4, (NH4)2CO3, NH4X (X = F, Cl), NH4SCN], thiocyanate (KSCN), nitrates (Cu(NO3)2, NaNO3), and nitrite (NaNO2). Among them, ammonium phosphates ((NH4)xH3-xPO4, x = 1–3) and ammonium thiocyanate (NH4SCN) are revealed to behave as better nitrogen sources than others, and the highest yield of Sc-NCFs is achieved when NH4SCN was used as a nitrogen source. The optimum molar ratio of Sc2O3:(NH4)3PO4·3H2O:C and Sc2O3:NH4SCN:C has been determined to be 1:2:15 and 1:3:15, respectively. The thermal decomposition products of these 12 inorganic compounds have been discussed in order to understand their different performances toward the synthesis of Sc-NCFs, and accordingly the dependence of the production yield of Sc-NCFs on the oxidation state of nitrogen and counter ion is interpreted. The yield of Sc3N@C80 (Ih + D5h) per gram Sc2O3 by using the N2-based group of nitrogen sources (thiocyanate, nitrates, and nitrite) is overall much lower than those by using gaseous N2 and NH4SCN, indicating the strong dependence of the yield of Sc-NCFs on the oxidation state of nitrogen, which is attributed to the “in-situ” redox reaction taking place for the N2-based group of nitrogen sources during discharging. For NH3-based group of nitrogen sources (ammonium salts) which exhibits a (−3) oxidation states of nitrogen, their performance as nitrogen sources is found to be sensitively dependent on the anion, and this is understood by considering their difference on the thermal stability and/or decomposition rate. Contrarily, for the N2-based group of nitrogen sources, the formation of Sc-NCFs is independent to both the oxidation state of nitrogen (+3 or +5) and the cation.
Co-reporter:Ilya N. Ioffe ; Olga N. Mazaleva ; Lev N. Sidorov ; Shangfeng Yang ; Tao Wei ; Erhard Kemnitz ;Sergey I. Troyanov
Inorganic Chemistry 2013 Volume 52(Issue 24) pp:13821-13823
Publication Date(Web):November 25, 2013
DOI:10.1021/ic402556g
A new case of chlorination-promoted fullerene cage shrinkage is reported. Chlorination of C90 (isolated pentagon rule isomer no. 28) with VCl4 afforded C88Cl22 with a nonclassic carbon cage (NCC) containing 1 heptagon and 13 pentagons including 2 fused pairs flanking the heptagon. The pathway of C2 abstraction from the C90 cage is suggested on the basis of density functional theory calculations.
Co-reporter:Shangfeng Yang, Tao Wei, Nadezhda B. Tamm, Erhard Kemnitz, and Sergey I. Troyanov
Inorganic Chemistry 2013 Volume 52(Issue 9) pp:4768-4770
Publication Date(Web):April 8, 2013
DOI:10.1021/ic400358e
Two derivatives of the low-abundant D2-C80 (isomer 2), C80(CF3)12 and C80Cl28, have been synthesized, isolated, and structurally characterized by single-crystal X-ray crystallography. Notably, the addition pattern of C80(CF3)12 is the same as that of the known C80Cl12. The molecule of C80Cl28 contains very short (1.33 Å) and very long (up to 1.62 Å) C–C bonds in its carbon cage.
Co-reporter: Shangfeng Yang;Tao Wei; Sergey I. Troyanov
Chemistry – An Asian Journal 2013 Volume 8( Issue 2) pp:351-353
Publication Date(Web):
DOI:10.1002/asia.201201038
Co-reporter:Shuxuan Qu, Minghua Li, Lixin Xie, Xiao Huang, Jinguo Yang, Nan Wang, and Shangfeng Yang
ACS Nano 2013 Volume 7(Issue 5) pp:4070
Publication Date(Web):April 15, 2013
DOI:10.1021/nn4001963
A new graphene–fullerene composite (rGO-pyrene-PCBM), in which [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was attached onto reduced graphene oxide (rGO) via the noncovalent functionalization approach, was reported. The pyrene-PCBM moiety was synthesized via a facile esterification reaction, and pyrene was used as an anchoring bridge to link rGO and PCBM components. FTIR, UV–vis, and XPS spectroscopic characterizations were carried out to confirm the hybrid structure of rGO-pyrene-PCBM, and the composite formation is found to improve greatly the dispersity of rGO in DMF. The geometric configuration of rGO-pyrene-PCBM was studied by Raman, SEM, and AFM analyses, suggesting that the C60 moiety is far from the graphene sheet and is bridged with the graphene sheet via the pyrene anchor. Finally rGO-pyrene-PCBM was successfully applied as electron extraction layer for P3HT:PCBM bulk heterojunction polymer solar cell (BHJ-PSC) devices, affording a PCE of 3.89%, which is enhanced by ca. 15% compared to that of the reference device without electron extraction layer (3.39%). Contrarily, the comparative devices incorporating the rGO or pyrene-PCBM component as electron extraction layer showed dramatically decreased PCE, indicating the importance of composite formation between rGO and pyrene-PCBM components for its electron extraction property.Keywords: electron extraction layer; graphene; polymer solar cells; pyrene; [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)
Co-reporter:Boxue Chen, Wenfeng Zhang, Xinghao Zhou, Xiao Huang, Xuemei Zhao, Haitao Wang, Min Liu, Yalin Lu, Shangfeng Yang
Nano Energy 2013 Volume 2(Issue 5) pp:906-915
Publication Date(Web):September 2013
DOI:10.1016/j.nanoen.2013.03.011
•Large Au@SiO2 core/shell nanoparticles (NPs) were incorporated into BHJ-PSC devices.•Au@SiO2 NPs were penetrated into all organic layers and partially embedded in Al cathode layer.•Au@SiO2 NPs-incorporated device exhibits an enhancement on both light absorption and Jsc.•The SiO2 shell provides an insulating barrier and plays the role of “surfactant”.•An efficiency enhancement by ∼16 % was achieved due to the LSPR effect.We report the incorporation of Au@SiO2 core/shell nanoparticles (NPs) into bulk heterojunction polymer solar cell (BHJ-PSC) devices, leading to an obvious efficiency enhancement due to the localized surface plasmon resonance (LSPR) effect. The Au@SiO2 core/shell NPs comprise of large Au NPs with an approximate size of 70 nm coated by a ∼50 nm thick SiO2 shell. Such NPs were doped into the poly-(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer of P3HT:PCBM BHJ-PSCs, resulting in that the large NPs penetrate into all organic layers including the PEDOT:PSS buffer layer and P3HT:PCBM active layer, and are partially embedded in the Al cathode layer. The power conversion efficiency (PCE) of the P3HT:PCBM BHJ-PSC devices incorporated with Au@SiO2 NPs increased from 3.29% to 3.80%, and such a ∼16% efficiency enhancement can be primarily attributed to the light absorption enhancement, originating from the LSPR effect induced by Au NPs as confirmed by the UV–vis absorption spectrocopic study. Contrarily, the analogous P3HT:PCBM BHJ-PSC devices incorporated with bare Au NPs exhibited a lower efficiency enhancement, indicating that the coating of dielectric SiO2 shell is beneficial for the LSPR effect.Graphical abstractLarge Au@SiO2 core/shell NPs were incorporated into P3HT:PCBM BHJ-PSC devices, resulting in the penetration of Au@SiO2 NPs into all organic layers. PCE of the device is enhanced by ∼16 % at the optimum Au@SiO2 NPs doping ratio of 2 wt%, and the efficiency enhancement is originated from the pure LSPR effect.
Co-reporter:Tong-Xin Liu ; Tao Wei ; San-E Zhu ; Guan-Wu Wang ; Mingzhi Jiao ; Shangfeng Yang ; Faye L. Bowles ; Marilyn M. Olmstead ;Alan L. Balch
Journal of the American Chemical Society 2012 Volume 134(Issue 29) pp:11956-11959
Publication Date(Web):July 12, 2012
DOI:10.1021/ja305446v
The reaction of an organic azide with an endohedral metallofullerene has been investigated for the first time. Isomeric [5,6]- and [6,6]-azafulleroids can be obtained from the thermal reaction of Sc3N@Ih-C80 with 4-isopropoxyphenyl azide, while photoirradiation leads exclusively to the [6,6]-azafulleroid. An unprecedented thermal interconversion between the two isomeric azafulleroids has also been discovered.
Co-reporter:Wenfeng Zhang, Haitao Wang, Boxue Chen, Xianghong Bi, Swaminathan Venkatesan, Qiquan Qiao and Shangfeng Yang
Journal of Materials Chemistry A 2012 vol. 22(Issue 45) pp:24067-24074
Publication Date(Web):27 Sep 2012
DOI:10.1039/C2JM35199D
An amphiphilic surfactant oleamide was incorporated into P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs) as a novel cathode buffer layer (CBL) for the first time by doping in the P3HT:PCBM photoactive layer followed by self-assembly. The power conversion efficiency (PCE) of the annealed P3HT:PCBM/oleamide BHJ-PSC device is enhanced by ∼28% at the optimum oleamide doping ratio of 2.5%, which is primarily due to the increase of fill factor (FF) by ∼22%. The surface morphologies of the oleamide-incorporated P3HT:PCBM photoactive films were studied by transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning Kelvin probe microscopy (SKPM), revealing that oleamide molecules initially doped in the P3HT:PCBM layer may undergo self-assembly and migrate to the top surface of the P3HT:PCBM layer, leading to the formation of a cathode buffer layer (CBL) as an interfacial dipole layer between the photoactive layer and Al cathode electrode. Such an oleamide interfacial dipole layer lowers the work function of Al, thus the energy level offset between the work function of Al and the LUMO level of the PCBM acceptor is decreased, facilitating the electron extraction by the Al cathode. Furthermore, we found that the crystallinity of P3HT upon the incorporation of oleamide was almost unchanged according to X-ray diffraction (XRD) characterization. It is noteworthy that, this phenomenon is completely different from the case of the previously reported analogous surfactant oleic acid, which was doped in the P3HT:PCBM photoactive layer and led to the efficiency enhancement as well due to the increased crystallinity of P3HT, suggesting the strong influence of the terminal group of the surfactant on its function in P3HT:PCBM BHJ-PSC devices.
Co-reporter:Chuanbao Chen ; Fupin Liu ; Shujuan Li ; Nan Wang ; Alexey A. Popov ; Mingzhi Jiao ; Tao Wei ; Qunxiang Li ; Lothar Dunsch
Inorganic Chemistry 2012 Volume 51(Issue 5) pp:3039-3045
Publication Date(Web):February 10, 2012
DOI:10.1021/ic202354u
Titanium/yttrium mixed metal nitride clusterfullerene (MMNCF) TiY2N@C80 has been successfully synthesized, representing the first Ti-containing non-scandium MMNCF. TiY2N@C80 has been isolated by multistep HPLC and characterized by various spectroscopies in combination with DFT computations. The electronic absorption property of TiY2N@C80 was characterized by UV–vis–NIR spectroscopy, indicating the resemblance to that of TiSc2N@C80 with broad shoulder absorptions. The optical band gap of TiY2N@C80 (1.39 eV) is very close to that of TiSc2N@C80 (1.43 eV) but much smaller than that of Y3N@C80(Ih, 1.58 eV). Such a resemblance of the overall absorption feature of TiY2N@C80 to TiSc2N@C80 suggests that TiY2N@C80 has a similar electronic configuration to that of TiSc2N@C80, that is, (TiY2N)6+@C806–. FTIR spectroscopic study and DFT calculations accomplish the assignment of the C80:Ih isomer to the cage structure of TiY2N@C80, with the C1 conformer being the lowest energy structure, which is different from the Cs conformer assigned to TiSc2N@C80. The electrochemical properties of TiY2N@C80 were investigated by cyclic voltammetry, revealing the reversible first oxidation and first reduction step with E1/2 at 0.00 and −1.13 V, respectively, both of which are more negative than those of TiSc2N@C80, while the electrochemical energy gap of TiY2N@C80 (1.11 V) is almost the same as that of TiSc2N@C80 (1.10 V). Contrary to the reversible first reduction step, the second and third reduction steps of TiY2N@C80 are irreversible, and this redox behavior is dramatically different from that of TiSc2N@C80, which shows three reversible reduction steps, indicating the strong influence of the encaged group-III metal (Y or Sc) on the electronic properties of TiM2N@C80 (M = Y, Sc).
Co-reporter:Dr. Shangfeng Yang;Tao Wei; Erhard Kemnitz;Dr. Sergey I. Troyanov
Chemistry – An Asian Journal 2012 Volume 7( Issue 2) pp:290-293
Publication Date(Web):
DOI:10.1002/asia.201100759
Co-reporter: Shangfeng Yang;Dr. Chuanbao Chen;Tao Wei;Dr. Nadezhda B. Tamm; Erhard Kemnitz; Sergey I. Troyanov
Chemistry - A European Journal 2012 Volume 18( Issue 8) pp:2217-2220
Publication Date(Web):
DOI:10.1002/chem.201103456
Co-reporter:Mingzhi Jiao;Wenfeng Zhang;Ying Xu;Tao Wei;Chuanbao Chen;Fupin Liu ;Dr. Shangfeng Yang
Chemistry - A European Journal 2012 Volume 18( Issue 9) pp:2666-2673
Publication Date(Web):
DOI:10.1002/chem.201101040
Abstract
By using urea as the new nitrogen source, for the first time, Sc-based metal nitride clusterfullerenes (NCFs), Sc3N@C2n (2n=80, 78, 70, 68), have been synthesized successfully. The optimum molar ratio of Sc2O3/CO(NH2)2/C for the synthesis of Sc NCFs is 1:3:15. The yield of Sc3N@C80 (Ih+D5h) per gram of Sc2O3, using CO(NH2)2 as the new nitrogen source, was quantitatively compared to those obtained when using the reported nitrogen sources, including N2, NH3, and guanidinium thiocyanate. We find that there is a clear difference on the selectivity of Sc-based NCFs within the extract mixture obtained from one rod and accumulative two rods. According to discharging experiments and XRD analysis, we conclude that NH3 generated in situ from the decomposition of CO(NH2)2 is mainly responsible for the formation of Sc-based NCFs when using only one rod, whereas in the second rod CO(NH2)2 would decompose into melamine during discharging of the first rod. Thus, the selectivity of fullerenes is clearly dependent on the decomposed product of CO(NH2)2. Finally the difference in the decomposition behavior of CO(NH2)2 and melamine was studied in detail and a possible decomposition process of CO(NH2)2 during discharging was proposed. Accordingly, the difference in the selectivity and yield of Sc NCFs for CO(NH2)2 and melamine was interpreted.
Co-reporter:Dr. Shangfeng Yang;Tao Wei;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Angewandte Chemie 2012 Volume 124( Issue 33) pp:8364-8367
Publication Date(Web):
DOI:10.1002/ange.201201775
Co-reporter:Dr. Shangfeng Yang;Tao Wei;Dr. Erhard Kemnitz;Dr. Sergey I. Troyanov
Angewandte Chemie International Edition 2012 Volume 51( Issue 33) pp:8239-8242
Publication Date(Web):
DOI:10.1002/anie.201201775
Co-reporter:Ying Xu, Chenchen He, Fupin Liu, Mingzhi Jiao and Shangfeng Yang
Journal of Materials Chemistry A 2011 vol. 21(Issue 35) pp:13538-13545
Publication Date(Web):02 Aug 2011
DOI:10.1039/C1JM11801C
Hexagonal nanorods of metal nitride clusterfullerene Sc3N@C80 (Ih) encapsulated in zinc meso-tetra(4-pyridyl) porphyrin (ZnTPyP) (Sc3N@C80-ZnTPyP nanorods) are prepared for the first time using a supramolecular approach. By introducing water as the solvent of cetyltrimethylammonium bromide (CTAB) surfactant, the effects of the solvent and the ratio of the reactants have been studied so as to control the length and size distribution of the Sc3N@C80-ZnTPyP nanorods. The encapsulation nature and hybrid structures of Sc3N@C80-ZnTPyP nanorods are confirmed by TEM, EDX, TGA and Raman spectroscopies. XRD study on the internal structure of Sc3N@C80-ZnTPyP nanorods suggests that ZnTPyP molecules tend to self-assemble in the axial direction. The UV-vis electronic absorption spectrum of Sc3N@C80-ZnTPyP nanorods shows broader and stronger absorptions in the visible region than those of the components Sc3N@C80 and ZnTPyP. The comparison of the UV-vis electronic absorption spectra of Sc3N@C80-ZnTPyP and C60-ZnTPyP nanorods reveals the influence of the electronic structures of fullerenes on the aggregative interactions between fullerene and ZnTPyP. The fluorescence emission intensity of Sc3N@C80-ZnTPyP nanorods exhibits a strong quenching (∼88%) compared to the pure ZnTPyP nanotubes, suggesting that photo-induced electron transfer from the excited ZnTPyP to Sc3N@C80 might occur. An electrochemical study of Sc3N@C80-ZnTPyP nanorods in comparison with those of ZnTPyP and Sc3N@C80 corroborate the hybrid nature of Sc3N@C80-ZnTPyP nanorods and reveal the interactions between Sc3N@C80 and ZnTPyP molecules.
Co-reporter:Shangfeng Yang, Fupin Liu, Chuanbao Chen, Mingzhi Jiao and Tao Wei
Chemical Communications 2011 vol. 47(Issue 43) pp:11822-11839
Publication Date(Web):30 Jun 2011
DOI:10.1039/C1CC12318A
Clusterfullerenes represent a novel branch of endohedral fullerenes, which are characterized by a robust fullerene cage with metal clusters encaged in its hollow. Since the discovery of nitride clusterfullerenes (NCFs) in 1999, the family of clusterfullerenes has been significantly expanded within the past decade, with new members including carbide clusterfullerenes (CCFs), hydrocarbide clusterfullerenes (HCCFs), oxide clusterfullerenes (OCFs), sulfide clusterfullerenes (SCFs), and carbonitride clusterfullerenes (CNCFs). We first present the classification of clusterfullerenes and list all the clusterfullerenes reported to date. For each type of clusterfullerenes, we review in detail their synthesis, separation, intriguing molecular structures and properties. For NCFs, as the first and most important clusterfullerenes, we point out the significance of their discovery and focus on their new synthesis and separation methods as well as the new advances. Finally the potential applications of clusterfullerenes are addressed. We conclude that clusterfullerenes appear to be the fastest growing family of endohedral fullerenes up to now, and emphasize the importance of exploring new structures and chemical functionalizations of clusterfullerenes.
Co-reporter:Shangfeng Yang ; Chuanbao Chen ; Mingzhi Jiao ; Nadezhda B. Tamm ; Maria A. Lanskikh ; Erhard Kemnitz ;Sergey I. Troyanov
Inorganic Chemistry 2011 Volume 50(Issue 8) pp:3766-3771
Publication Date(Web):March 21, 2011
DOI:10.1021/ic200174u
Sc3N@D5h-C80 and Sc3N@Ih-C80 were trifluoromethylated with CF3I at 400 °C, affording mixtures of CF3 derivatives. After separation with HPLC, the first multi-CF3 derivative of Sc3N@D5h-C80, Sc3N@D5h-C80(CF3)18, and three new isomers of Sc3N@Ih-C80(CF3)14 were investigated by X-ray crystallography. The Sc3N@D5h-C80(CF3)18 molecule is characterized by a large number of double C−C bonds and benzenoid rings within the D5h-C80 cage and a fully different position of the Sc3N unit compared to that in the pristine Sc3N@D5h-C80. A detailed comparison of five Sc3N@Ih-C80(CF3)14 isomers reveals a strong influence of the exohedral additions on the behavior of the Sc3N cluster inside the Ih-C80 cage.
Co-reporter:Minghua Li ; Pan Xu ; Jinguo Yang ; Hong Ying ; Kinga Haubner ; Lothar Dunsch
The Journal of Physical Chemistry C 2011 Volume 115(Issue 11) pp:4584-4593
Publication Date(Web):February 25, 2011
DOI:10.1021/jp112330n
A novel pyrene-functionalized poly(3-hexylthiophene) (P3HT) derivative (Pyrene-P3HT) has been successfully synthesized via a postpolymerization approach, and its noncovalent interactions with SWNTs are studied in detail based on its composite of SWNT (SWNT/Pyrene-P3HT). The molecular structure of Pyrene-P3HT is confirmed by 1H NMR spectroscopy, revealing a ca. 15% substitution ratio of pyrene within Pyrene-P3HT. The noncovalent interactions between SWNT and Pyrene-P3HT are studied by UV−vis/NIR and Raman spectroscopy as well as ESR spectroelectrochemical experiments and compared to those between SWNT and P3HT. The UV−vis/NIR spectra of SWNT/Pyrene-P3HT are found to be independent of the blending ratio of SWNTs and Pyrene-P3HT, indicating that the electronic structures of SWNTs are basically intact after blending Pyrene-P3HT. Raman spectra of SWNT/Pyrene-P3HT and SWNT/P3HT are quite different, pointing to their difference on the interactions between SWNTs and P3HT. The in situ ESR spectroelectrochemical study of SWNT/Pyrene-P3HT reveals that Pyrene-P3HT interacts with SWNTs via the noncovalent π−π bonding interactions of pyrene moieties and SWNTs and thus the attached P3HT main chain is prevented from any further interaction with the surface of SWNTs. These studies reveal the remarkable difference on the interactions between SWNTs and P3HT within SWNT/Pyrene-P3HT and SWNT/P3HT composites. The fluorescence intensity of SWNT/Pyrene-P3HT is quenched by nearly 100% compared to that of Pyrene-P3HT, suggesting that a strong photoinduced electron transfer resulting from the noncovalent linkage of SWNTs to the P3HT backbone via the pyrene bridge takes place upon photoexcitation. Finally, the SEM study on the film morphology of SWNT/Pyrene-P3HT-1 shows that the bundles of SWNTs become bigger and fewer compared to the pristine SWNTs, and the further increase of the content of Pyrene-P3HT within SWNT/Pyrene-P3HT leads to the formation of smooth film, suggesting that SWNTs are well dispersed in THF by Pyrene-P3HT, as confirmed by TEM study.
Co-reporter:Dr. Shangfeng Yang;Chuanbao Chen;Maria A. Lanskikh;Dr. Nadezhda B. Tamm; Erhard Kemnitz;Dr. Sergey I. Troyanov
Chemistry – An Asian Journal 2011 Volume 6( Issue 2) pp:505-509
Publication Date(Web):
DOI:10.1002/asia.201000661
Abstract
Sc3N@C80 (Ih) was trifluoromethylated with CF3I at 400 °C affording a mixture of CF3 derivatives. Two isomers of Sc3N@C80(CF3)14 and Sc3N@C80(CF3)16 were separated by HPLC and investigated by X-ray crystallography. Detailed comparison of the four isomers revealed a strong influence of the exohedral CF3 addition pattern on the behavior of the Sc3N cluster inside the C80 fullerene cage.
Co-reporter:Dr. Guan-Wu Wang;Tong-Xin Liu;Mingzhi Jiao;Nan Wang;San-E Zhu;Chuanbao Chen;Dr. Shangfeng Yang;Faye L. Bowles;Dr. Christine M. Beavers;Dr. Marilyn M. Olmstead;Bron Q. Mercado;Dr. Alan L. Balch
Angewandte Chemie International Edition 2011 Volume 50( Issue 20) pp:4658-4662
Publication Date(Web):
DOI:10.1002/anie.201100510
Co-reporter:Wenfeng Zhang, Ying Xu, Haitao Wang, Chenhui Xu, Shangfeng Yang
Solar Energy Materials and Solar Cells 2011 95(10) pp: 2880-2885
Publication Date(Web):
DOI:10.1016/j.solmat.2011.06.005
Co-reporter:Minghua Li, Pan Xu, Jinguo Yang and Shangfeng Yang
Journal of Materials Chemistry A 2010 vol. 20(Issue 19) pp:3953-3960
Publication Date(Web):15 Mar 2010
DOI:10.1039/B925398J
A novel type of donor-π-acceptor double cable poly(3-hexylthiophene) (P3HT) derivative bearing a fullerene pendant and a phenyl group as the linking bridge between the P3HT donor and C60 acceptor (C60-Ph-P3HT-1,2,3,4) with tunable donor/acceptor ratio was synthesized via a facile postpolymerization functionalization. The molecular structure, electronic property and molecular arrangement, as well as the surface morphology of the synthesized C60-Ph-P3HT-1,2,3,4 were characterized by FTIR, 1H NMR, UV-Vis and fluorescence emission spectroscopies, XRD and AFM. FTIR and 1H NMR spectroscopic studies confirm the polymeric structures of C60-Ph-P3HT-1,2,3,4 with the successful grafting of the C60 moiety with tunable donor/acceptor ratio (wt.% ∼1:1; 1:0.9; 1:0.8; 1:0.6). UV-Vis absorption spectroscopic study confirms the nature of C60-Ph-P3HT as the mono-adduct of C60, and indicates a very weak perturbation of the molecular arrangement of the P3HT backbone upon the grafting of the C60 pendant. The fluorescence intensity of C60-Ph-P3HT-1,2,3,4 is found to be dramatically quenched compared to that of the P3HT and P3HT/C60 (1:1) blend, and notably, C60-Ph-P3HT-1 approaches 98% quenching. The molecular arrangement of C60-Ph-P3HT is investigated by XRD analysis, suggesting that the grafted C60 moieties in the side chain slightly interferes with the lamellar stacking of the polythiophene main chain of P3HT. The AFM measurements on the surface film morphology of C60-Ph-P3HT-1,2,3,4 reveal that the rms roughness of C60-Ph-P3HT-1,2,3,4 is larger than that of P3HT.
Co-reporter:Chuanbao Chen, Xiaofang Li and Shangfeng Yang
New Journal of Chemistry 2010 vol. 34(Issue 2) pp:331-336
Publication Date(Web):09 Dec 2009
DOI:10.1039/B9NJ00420C
One-pot Prato reactions of C60 with amino acids and aldehydes afford five new fullerene derivatives, including two unexpected thiazolidine and oxazolidine fulleropyrrolidines. In particular, L-cysteine (1), paraformaldehyde and C60 in refluxing toluene solution affords an unexpected new thiazolidine-fulleropyrrolidine derivative 3 (instead of 2) via 1,3-dipolar cycloaddition, whose structure was characterized in detail. A possible reaction mechanism for the formation of 3 is proposed. These suggest that the active hydrogen of S–H in 1 is essential for the formation of the thiazolidine ring in 3. To confirm further this conclusion, reactions of C60 with different amino acids (5, 7) and aldehydes (3-(methylthio)proplonaldehyde (9) and 2-thiophenaldehyde (11)) were also studied, resulting in the synthesis of other three new thio-derivatives of C60 (6, 10, 12) as well as an oxazolidine fulleropyrrolidine (8).
Co-reporter:Minghua Li;Xiaofang Li;Pan Xu
Macromolecular Chemistry and Physics 2010 Volume 211( Issue 4) pp:443-452
Publication Date(Web):
DOI:10.1002/macp.200900447
Co-reporter:Alexey A. Popov, Chuanbao Chen, Shangfeng Yang, Ferdinand Lipps and Lothar Dunsch
ACS Nano 2010 Volume 4(Issue 8) pp:4857
Publication Date(Web):July 23, 2010
DOI:10.1021/nn101115d
The recently isolated TiSc2N@C80 was used to study the spin state of a Ti3+ ion in a mixed metal nitride cluster in a fullerene cage. The electronic state of the new clusterfullerene is characterized starting with the redox behavior of this structure. It differs markedly from that of homometallic nitride clusterfullerenes in giving reversible one-electron transfers even on the cathodic scale. Both oxidation and reduction of TiSc2N@C80 occur at the endohedral cluster changing the valence state of Ti from Ti(II) in anion to Ti(IV) in cation. The unpaired electron in TiSc2N@C80 is largely fixed at the Ti ion as shown by low temperature ESR measurements. Isotropic g-factor 1.9454 points to the significant spin−orbit coupling with an unquenched orbital momentum of the 3d electron localized on Ti. Measurements with the frozen solution also point to the strong anisotropy of the g-tensor. DFT computations show that the cluster can adopt several nearly isoenergetic configurations. DFT-based Born−Oppenheimer molecular dynamics (BOMD) simulations reveal that, unlike in Sc3N@C80, the cluster dynamics in TiSc2N@C80 cannot be described as a 3D rotation. The cluster rotates around the Ti−N axis, while the Ti atom oscillates in one position around the pentagon/hexagon edge. Evolution of the spin populations along the BOMD trajectory has shown that the spin distribution in the cluster is very flexible, and both an intracluster and cluster-cage spin flows take place. Fourier transformation of the time dependencies of the spin populations results in the spin-flow vibrational spectra, which reveal the major spin-flow channels. It is shown that the cluster-cage spin flow is selectively coupled to one vibrational mode, thus, pointing to the utility of the clusterfullerene for the molecular spin transport. Spin-flow vibrational spectroscopy is thus shown to be a useful method for characterization of the spin dynamics in radicals with flexible spin density distribution.Keywords: DFT computations; electronic structure; endohedral fullerenes; ESR spectroscopy; molecular dynamics; nitride clusterfullerene; QTAIM; spin transport
Co-reporter:Dr. Shangfeng Yang;Lin Zhang;Wenfeng Zhang;Dr. Lothar Dunsch
Chemistry - A European Journal 2010 Volume 16( Issue 41) pp:12398-12405
Publication Date(Web):
DOI:10.1002/chem.201001252
Abstract
Using guanidinium salts 1 and 2 as the new nitrogen sources, metal nitride clusterfullerenes (NCFs) based on a variety of metals (Dy, Sc, Y, Gd, Lu, and mixed metals Sc/Dy, Sc/Gd, Sc/Lu, and Lu/Ce) have been synthesized based on a new “selective organic solid” (SOS) route. The synthesis of Dy-NCFs by using Dy/1 was studied in detail, and the optimum molar ratio of 1/Dy/C has been determined to be 2.5:1:10. For several representative metals such as Sc, Y, Gd, Dy, and Sc/Dy, we quantitatively compared the yield of M3N@C80 synthesized by the SOS route with the reported “reactive gas atmosphere” route, thereby indicating that the yield of M3N@C80 by using 1 could be comparable to that obtained by the reactive gas atmosphere route. Three other nitrogen sources (3–5) were also studied for comparison, which were mixed with Dy metal but did not result in the formation of Dy-NCF. A possible reaction scheme for the solid-state reaction of 1, metal, and graphite is proposed. The SOS route appears to be a general route for the synthesis of NCFs that promises both high selectivity of NCFs and high reproducibility of the fullerene yield. Another advantages of the SOS route compared to the reported “trimetallic nitride template” (TNT) process and the reactive gas atmosphere route is that no additional heating pretreatment is needed, thus simplifying the procedure and being much more facile.
Co-reporter:Shangfeng Yang, Chuanbao Chen, Alexey A. Popov, Wenfeng Zhang, Fupin Liu and Lothar Dunsch
Chemical Communications 2009 (Issue 42) pp:6391-6393
Publication Date(Web):24 Sep 2009
DOI:10.1039/B911267G
With the successful isolation of TiSc2N@C80, the first Ti-containing nitride clusterfullerene (NCF), a non-group-III metal is stabilized in a NCF for the first time.
Co-reporter:Shangfeng Yang, Alexey A. Popov, Chuanbao Chen and Lothar Dunsch
The Journal of Physical Chemistry C 2009 Volume 113(Issue 18) pp:7616-7623
Publication Date(Web):April 9, 2009
DOI:10.1021/jp9005263
Two isomers of lutetium−scandium mixed metal nitride clusterfullerenes (MMNCFs), LuxSc3−xN@C80(x = 1, 2), have been synthesized and isolated for the first time, and accordingly, the interplay of the cluster structure and cage isomerism is followed. The electronic and vibrational properties of LuxSc3−xN@C80 (I, II, x = 1, 2) are characterized by UV−vis−NIR and FTIR spectroscopies, revealing the effect of the composition of the encaged LuxSc3−xN cluster. A comparative study of LuxSc3−xN@C80 (I) with other MxSc3−xN@C80(I; M = Er, Dy, Gd, Nd) MMNCFs points to the dependence of their electronic and vibrational properties on the encaged metal. The cage structures of LuxSc3−xN@C80 (I, II; x = 1, 2) are determined by 13C NMR spectroscopy. The 45Sc NMR spectroscopic study is carried out to probe the dynamics of the encaged Sc atoms. Finally, DFT computations are used to address the effect of the composition of the encaged LuxSc3−xN cluster on the NMR lines and the structures of LuxSc3−xN@C80 (I, II; x = 1, 2) especially with respect to the carbon atoms.
Co-reporter:Shangfeng Yang Dr.;AlexeyA. Popov Dr.;Lothar Dunsch Dr.
Angewandte Chemie 2008 Volume 120( Issue 43) pp:8318-8322
Publication Date(Web):
DOI:10.1002/ange.200802009
Co-reporter:Shangfeng Yang Dr.;AlexeyA. Popov Dr.;Lothar Dunsch Dr.
Angewandte Chemie International Edition 2008 Volume 47( Issue 43) pp:8196-8200
Publication Date(Web):
DOI:10.1002/anie.200802009
Co-reporter:Shangfeng Yang, Fupin Liu, Chuanbao Chen, Mingzhi Jiao and Tao Wei
Chemical Communications 2011 - vol. 47(Issue 43) pp:NaN11839-11839
Publication Date(Web):2011/06/30
DOI:10.1039/C1CC12318A
Clusterfullerenes represent a novel branch of endohedral fullerenes, which are characterized by a robust fullerene cage with metal clusters encaged in its hollow. Since the discovery of nitride clusterfullerenes (NCFs) in 1999, the family of clusterfullerenes has been significantly expanded within the past decade, with new members including carbide clusterfullerenes (CCFs), hydrocarbide clusterfullerenes (HCCFs), oxide clusterfullerenes (OCFs), sulfide clusterfullerenes (SCFs), and carbonitride clusterfullerenes (CNCFs). We first present the classification of clusterfullerenes and list all the clusterfullerenes reported to date. For each type of clusterfullerenes, we review in detail their synthesis, separation, intriguing molecular structures and properties. For NCFs, as the first and most important clusterfullerenes, we point out the significance of their discovery and focus on their new synthesis and separation methods as well as the new advances. Finally the potential applications of clusterfullerenes are addressed. We conclude that clusterfullerenes appear to be the fastest growing family of endohedral fullerenes up to now, and emphasize the importance of exploring new structures and chemical functionalizations of clusterfullerenes.
Co-reporter:Shangfeng Yang, Chuanbao Chen, Alexey A. Popov, Wenfeng Zhang, Fupin Liu and Lothar Dunsch
Chemical Communications 2009(Issue 42) pp:NaN6393-6393
Publication Date(Web):2009/09/24
DOI:10.1039/B911267G
With the successful isolation of TiSc2N@C80, the first Ti-containing nitride clusterfullerene (NCF), a non-group-III metal is stabilized in a NCF for the first time.
Co-reporter:Weiran Zhou, Jieming Zhen, Qing Liu, Zhimin Fang, Dan Li, Pengcheng Zhou, Tao Chen and Shangfeng Yang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 4) pp:NaN1733-1733
Publication Date(Web):2016/12/13
DOI:10.1039/C6TA07876A
Interfacial engineering is critical for highly efficient charge carrier transport in perovskite solar cells (PSCs). Herein, we developed a new method, called successive surface engineering, that affords PSCs with enhanced efficiency and dramatically suppressed current–voltage hysteresis. Upon modifying the TiO2 compact layer, which is commonly used as an electron transport layer (ETL) in regular-structure (n–i–p) planar heterojunction (PHJ) PSCs, by successively incorporating [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) and an ethanolamine (ETA)-functionalized fullerene (C60-ETA) synthesized facilely via a one-pot nucleophilic addition reaction, the average power conversion efficiency (PCE) of the CH3NH3PbI3-based PHJ-PSC devices increased from 13.00% to 16.31%; the best PCE attained was 18.49%, which, to our knowledge, represents the highest PCE reported to date for regular-structure PHJ-PSCs devices based on fullerene-modified TiO2 interlayers. In contrast, single surface engineering of the TiO2 layer with a PC61BM or C60-ETA layer alone results in only negligible changes in PCE, revealing the synergistic effect of these two fullerene derivatives: the PC61BM layer can passivate the traps on the TiO2 surface, while the subsequent C60-ETA layer not only improves the wettability of the perovskite film on the ETL but also facilitates electron transport across the interface between the perovskite and the TiO2 ETL. The structural and morphological characterizations show that following dual surface modification of the TiO2 layer with PC61BM and C60-ETA, both the surface coverage and crystallinity of the CH3NH3PbI3 perovskite film are improved. Steady-state photoluminescence decay and electrochemical impedance spectroscopic studies manifest that the dual surface modification substantially improves the charge extraction efficiency and suppresses charge recombination. As a consequence, this dual surface modification leads to an obvious increase of the short-circuit current density (Jsc), which contributes primarily to the PCE enhancement. Additionally, because PC61BM may induce passivation of the traps on the TiO2 surface and in the perovskite layer, remarkably, the hysteresis of the current–voltage response is dramatically suppressed following the dual surface modification.
Co-reporter:Minghua Li, Pan Xu, Jinguo Yang and Shangfeng Yang
Journal of Materials Chemistry A 2010 - vol. 20(Issue 19) pp:NaN3960-3960
Publication Date(Web):2010/03/15
DOI:10.1039/B925398J
A novel type of donor-π-acceptor double cable poly(3-hexylthiophene) (P3HT) derivative bearing a fullerene pendant and a phenyl group as the linking bridge between the P3HT donor and C60 acceptor (C60-Ph-P3HT-1,2,3,4) with tunable donor/acceptor ratio was synthesized via a facile postpolymerization functionalization. The molecular structure, electronic property and molecular arrangement, as well as the surface morphology of the synthesized C60-Ph-P3HT-1,2,3,4 were characterized by FTIR, 1H NMR, UV-Vis and fluorescence emission spectroscopies, XRD and AFM. FTIR and 1H NMR spectroscopic studies confirm the polymeric structures of C60-Ph-P3HT-1,2,3,4 with the successful grafting of the C60 moiety with tunable donor/acceptor ratio (wt.% ∼1:1; 1:0.9; 1:0.8; 1:0.6). UV-Vis absorption spectroscopic study confirms the nature of C60-Ph-P3HT as the mono-adduct of C60, and indicates a very weak perturbation of the molecular arrangement of the P3HT backbone upon the grafting of the C60 pendant. The fluorescence intensity of C60-Ph-P3HT-1,2,3,4 is found to be dramatically quenched compared to that of the P3HT and P3HT/C60 (1:1) blend, and notably, C60-Ph-P3HT-1 approaches 98% quenching. The molecular arrangement of C60-Ph-P3HT is investigated by XRD analysis, suggesting that the grafted C60 moieties in the side chain slightly interferes with the lamellar stacking of the polythiophene main chain of P3HT. The AFM measurements on the surface film morphology of C60-Ph-P3HT-1,2,3,4 reveal that the rms roughness of C60-Ph-P3HT-1,2,3,4 is larger than that of P3HT.
Co-reporter:Wenfeng Zhang, Haitao Wang, Boxue Chen, Xianghong Bi, Swaminathan Venkatesan, Qiquan Qiao and Shangfeng Yang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 45) pp:NaN24074-24074
Publication Date(Web):2012/09/27
DOI:10.1039/C2JM35199D
An amphiphilic surfactant oleamide was incorporated into P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs) as a novel cathode buffer layer (CBL) for the first time by doping in the P3HT:PCBM photoactive layer followed by self-assembly. The power conversion efficiency (PCE) of the annealed P3HT:PCBM/oleamide BHJ-PSC device is enhanced by ∼28% at the optimum oleamide doping ratio of 2.5%, which is primarily due to the increase of fill factor (FF) by ∼22%. The surface morphologies of the oleamide-incorporated P3HT:PCBM photoactive films were studied by transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning Kelvin probe microscopy (SKPM), revealing that oleamide molecules initially doped in the P3HT:PCBM layer may undergo self-assembly and migrate to the top surface of the P3HT:PCBM layer, leading to the formation of a cathode buffer layer (CBL) as an interfacial dipole layer between the photoactive layer and Al cathode electrode. Such an oleamide interfacial dipole layer lowers the work function of Al, thus the energy level offset between the work function of Al and the LUMO level of the PCBM acceptor is decreased, facilitating the electron extraction by the Al cathode. Furthermore, we found that the crystallinity of P3HT upon the incorporation of oleamide was almost unchanged according to X-ray diffraction (XRD) characterization. It is noteworthy that, this phenomenon is completely different from the case of the previously reported analogous surfactant oleic acid, which was doped in the P3HT:PCBM photoactive layer and led to the efficiency enhancement as well due to the increased crystallinity of P3HT, suggesting the strong influence of the terminal group of the surfactant on its function in P3HT:PCBM BHJ-PSC devices.
Co-reporter:Jieming Zhen, Qing Liu, Xiang Chen, Dan Li, Qiquan Qiao, Yalin Lu and Shangfeng Yang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 21) pp:NaN8079-8079
Publication Date(Web):2016/04/21
DOI:10.1039/C6TA02016J
An ethanolamine (ETA)-functionalized fullerene (C60-ETA) was synthesized by using a facile one-pot addition reaction, and applied as an efficient electron transport layer (ETL) for inverted polymer solar cells (iPSCs) with the efficiency exceeding 9.5%, which represents the highest power conversion efficiency (PCE) reported so far for iPSC devices with independent fullerene derivative ETLs. The chemical structure of C60-ETA was studied by FT-IR and XPS spectroscopies and elemental analysis, and the average molecular formula of C60-ETA is estimated to be C60(NHC2H4OH)8(H)8 with an average ETA addition number of eight. C60-ETA was applied as an ETL for bulk heterojunction (BHJ) iPSC devices based on different photoactive layers including poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]:[6,6]-phenyl C71-butyric acid methyl ester (PTB7-Th:PC71BM), poly(4,8-bis-alkyloxybenzo(l,2-b:4,5-b′)dithiophene-2,6-diylalt-(alkyl thieno(3,4-b)thiophene-2-carboxylate)-2,6-diyl) (PBDTTT-C):PC71BM and poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PC61BM), leading to the best PCE of 9.55%, 6.50% and 4.18%, respectively, which are all higher than those of the corresponding reference devices based on the ZnO ETL. The PCE improvement of the C60-ETA device relative to that of the ZnO device primarily originates from the increase of short-circuit current density (Jsc), which is due to the smoothened ETL surface and the increase of electron mobility, facilitating electron transport from the active layer to the ITO cathode.
Co-reporter:Jian Guan, Xiang Chen, Tao Wei, Fupin Liu, Song Wang, Qing Yang, Yalin Lu and Shangfeng Yang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 8) pp:NaN4146-4146
Publication Date(Web):2014/11/24
DOI:10.1039/C4TA05456C
Using a facile solid-state mechanochemical method by ball milling, we successfully synthesized the first directly bonded graphene–C60 hybrid, for which LiOH is found to play a crucial role as the catalyst. The hybrid structure of graphene–C60 is confirmed by FTIR, Raman, XRD and XPS characterizations, and its conformation is proposed, featuring the direct bonding of graphene nanoplatelets and C60via two C–C single bonds. SEM measurement suggests that severe edge distortions occur for graphene–C60 hybrid, and HR-TEM study indicate the covalent attaching of C60 molecules onto the edge of graphene nanoplatelets. The graphene–C60 hybrid is applied as a carbon-based electrocatalyst toward oxygen reduction reaction (ORR), showing improved ORR electrocatalytic activity than the pristine graphite.
Co-reporter:Shangfeng Yang, Chuanbao Chen, Xiaofang Li, Tao Wei, Fupin Liu and Song Wang
Chemical Communications 2013 - vol. 49(Issue 92) pp:NaN10846-10846
Publication Date(Web):2013/09/30
DOI:10.1039/C3CC46277C
The first Bingel–Hirsch reaction of TiSc2N@Ih-C80 afforded two unconventional singly bonded monoadducts, revealing the dramatically improved reactivity compared to Sc3N@Ih-C80 and obvious change in the addition pattern.
Co-reporter:Shangfeng Yang, Tao Wei, Song Wang, Daria V. Ignat'eva, Erhard Kemnitz and Sergey I. Troyanov
Chemical Communications 2013 - vol. 49(Issue 72) pp:NaN7946-7946
Publication Date(Web):2013/07/11
DOI:10.1039/C3CC44386H
The chlorination of a pristine C102 fullerene separated by HPLC from fullerene soot afforded crystals of C102Cl20 with a non-IPR (IPR = isolated pentagon rule) cage containing two pairs of fused pentagons; structural reconstruction of a two-step Stone–Wales rearrangement revealed the starting IPR isomer (no. 19) of C102.
Co-reporter:Ying Xu, Chenchen He, Fupin Liu, Mingzhi Jiao and Shangfeng Yang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 35) pp:NaN13545-13545
Publication Date(Web):2011/08/02
DOI:10.1039/C1JM11801C
Hexagonal nanorods of metal nitride clusterfullerene Sc3N@C80 (Ih) encapsulated in zinc meso-tetra(4-pyridyl) porphyrin (ZnTPyP) (Sc3N@C80-ZnTPyP nanorods) are prepared for the first time using a supramolecular approach. By introducing water as the solvent of cetyltrimethylammonium bromide (CTAB) surfactant, the effects of the solvent and the ratio of the reactants have been studied so as to control the length and size distribution of the Sc3N@C80-ZnTPyP nanorods. The encapsulation nature and hybrid structures of Sc3N@C80-ZnTPyP nanorods are confirmed by TEM, EDX, TGA and Raman spectroscopies. XRD study on the internal structure of Sc3N@C80-ZnTPyP nanorods suggests that ZnTPyP molecules tend to self-assemble in the axial direction. The UV-vis electronic absorption spectrum of Sc3N@C80-ZnTPyP nanorods shows broader and stronger absorptions in the visible region than those of the components Sc3N@C80 and ZnTPyP. The comparison of the UV-vis electronic absorption spectra of Sc3N@C80-ZnTPyP and C60-ZnTPyP nanorods reveals the influence of the electronic structures of fullerenes on the aggregative interactions between fullerene and ZnTPyP. The fluorescence emission intensity of Sc3N@C80-ZnTPyP nanorods exhibits a strong quenching (∼88%) compared to the pure ZnTPyP nanotubes, suggesting that photo-induced electron transfer from the excited ZnTPyP to Sc3N@C80 might occur. An electrochemical study of Sc3N@C80-ZnTPyP nanorods in comparison with those of ZnTPyP and Sc3N@C80 corroborate the hybrid nature of Sc3N@C80-ZnTPyP nanorods and reveal the interactions between Sc3N@C80 and ZnTPyP molecules.
![21H,23H-Porphine, 5,10,15,20-tetrakis[[tris(1-methylethyl)silyl]ethynyl]- (9CI)](/data/chemimg/3085100/202524-81-0.png)
![21H,23H-Porphine, 5,10,15,20-tetrakis[[tris(1-methylethyl)silyl]ethynyl]- (9CI)](/data/chemimg/3085100/202524-81-0_b.png)
![Nickel, [2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphinato(2-)-κN21,κN22,κN23,κN24]-, (SP-4-1)-](/data/chemimg/2500/24803-99-4.png)
![Nickel, [2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphinato(2-)-κN21,κN22,κN23,κN24]-, (SP-4-1)-](/data/chemimg/2500/24803-99-4_b.png)