•Two novel β-functionalized D-A-π-A porphyrins are designed and synthesized.•Introduction of additional acceptors in sensitizers influence the optoelectronic properties.•A more electron-withdrawing acceptor is optimal for the enhancement of cell efficiency.The β-functionalized porphyrin containing an additional electron-withdrawing unit, 2,3-diphenylquinoxaline(DPQ) for LP-5 or 2,1,3-benzothiadiazole (BTD) for LP-6 with different electron-withdrawing abilities, between the porphyrin core and the anchoring group and the reference porphyrin dye (LP-4) have been designed and synthesized for DSCs. The influence of the additional electron-withdrawing units on molecular properties as well as photovoltaic performance of the corresponding DSCs was investigated systematically. Compared with LP-4, the introduction of additional electron-deficient unit at the porphyrin β π-linker in LP-5 and LP-6 decreases the lowest unoccupied molecular orbital (LUMO) energy levels, resulting in the broader absorption spectra and significantly improved IPCE spectra in the region 350–500 nm, which ensures the better light-harvesting properties and the higher short-circuit current density (Jsc). On the other hand, the introduction of additional acceptors of LP-5 and LP-6 induces dye aggregation and reduces the lifetime of the charge–separated states, which decreases the open–circuit voltage (Voc). Interestingly, the loss in Voc is overcompensated by the improvement in Jsc. The study provides not only an alternative approach to design novel porphyrin sensitizers, but also an insight into how to manipulate the LUMO energy levels of porphyrin sensitizers via the β-linker modifications for the optimal photovoltaic applications.

A novel organogelator (F-6) with multiple hydroxyl groups and a ferrocene group was designed and synthesized. F-6/chloroform gel exhibited smart thixotropic property and displayed stimuli responsiveness to temperature, mechanical stress, redox, anions and cations. Further, a gel–sol phase transition was observed when halogen anions (F−, Cl−, Br−) were added. In particular, only the addition of F− converted the color of the gel from orange to red and was therefore unique for F−. More interestingly, Al3+ could also be recognized by the naked eye through the color change and gel–sol transition. The conclusive stoichiometric ratio between F-6 and Al3+ was determined to be 2 : 1. The detection limit of Al3+ by using F-6 for the analysis was calculated to be 6.84 × 10−7 M in CH3OH/H2O (8 : 2, v/v) at room temperature, which is far below the World Health Organization's (WHO) acceptable limit (1.85 μM of Al3+). Thus, the recognition of F− and Al3+ was achieved through the F-6/chloroform gel system, which was uncommon among organogels. It was shown that the ferrocene group played an important role in the response to ions.

Based on gluconic acid acetal and terpyridyl groups, we have prepared two new supramolecular gelators C3S and C6S with the critical gelation concentrations of 0.1% in aryl halides and the ability of gelling in DMF/DMSO + H2O at room temperature. The excellent self-healing properties of the gels were studied using rheological experiments. Based on the 1H NMR, IR spectrum and PXRD, the self-assembly pattern of C6S was proposed through theoretical calculation. After coordinating with Ln(III) metal ions, the multicolor luminescent metallogel C6S–Eu/Tb was investigated. The luminescence properties of the gels were characterized by fluorescence spectroscopy and fluorescence lifetime measurements, confirming the energy transfer between the organic compounds and Ln(III) metal ions.

The development of efficient catalysts with a visible-light response is of great importance in photocatalysis. Porphyrinic metal-organic frameworks (porph-MOFs) have recently been shown as promising photocatalyst candidates due to their large surface area, high visible light harvesting efficiency, and semiconductive properties, but challenges still remain because of their rapid charge recombination. Herein, we report the design of an effectively visible-light-driven composite material, namely TP-222(Zn), containing zirconium-based porph-MOF PCN-222(Zn) linked TiO2 nanoparticles (NPs) via the compound 4-mercaptopyridine which is axially bonded to the porphyrin central Zn metal in the PCN-222(Zn) and anchored onto the surface of TiO2 NPs. The resulting composite material demonstrates the high dispersion of TiO2 NPs and their close contact with the porph-MOF matrix, and serves as an effective photocatalyst for degrading organic contaminants under visible light irradiation due to their synergistic effect. It is further confirmed by fluorescence spectroscopy and electrochemical impedance spectroscopy that the remarkably enhanced photocatalytic activity of the TP-222(Zn) composite is attributed to the efficient charge separation with electron injection from PCN-222(Zn) to TiO2 NPs. In addition, the TP-222(Zn) composite shows excellent stability and recyclability as a result of the axially coordinative interaction between TiO2 NPs/PCN-222(Zn) and the 4-mercaptopyridine. Overall, this work provides a new strategy for the fabrication of highly efficient porph-MOF-based composite materials for visible light-driven photocatalysis.

The gelation behaviours of low molecular weight gelators 1,3:2,5:4,6-tris(3,4-dichlorobenzylidene)-d-mannitol (G1) and 2,4-(3,4-dichlorobenzylidene)-N-(3-aminopropyl)-d-gluconamide (G2) in 34 solvents have been studied. We found that sample dissolved at low concentrations may become a gel or precipitate at higher concentrations. The Hansen solubility parameters (HSPs) and a Teas plot were employed to correlate the gelation behaviours with solvent properties, but with no success if the concentration of the tests was not maintained constant. Instead, on the basis of the gelation results obtained for the G1 and G2 in single solvents, we studied the gelation behaviours of G1 and G2 in 23 solvent mixtures and found that the tendency of a gelator to form a gel in mixed solvents is strongly correlated with its gelation behaviours in good solvents. If the gelation occurs in a good solvent at higher concentrations, it will take place as well in a mixed solvent (the good solvent plus a poor solvent) at a certain volume ratio. In contrast, if the gelator forms a precipitate in a good solvent at higher concentrations, no gelation is to be observed in the mixed solvents. A gelation rule for mixed solvents is thus proposed, which may facilitate decision making with regard to solvent selection for gel formation in the solvent mixtures in practical applications.The tendency of a gelator to form a gel in mixed solvents is strongly correlated with its gelation behaviours in good solvents.Download high-res image (94KB)Download full-size image

The performance of dye-sensitized solar cells (DSSCs) consisting of anatase TiO2 nanoparticles that were synthesized via a hydrothermal method was studied. The synthesized TiO2 nanoparticles were characterized by X-ray diffraction (XRD), nitrogen sorption analysis, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and UV–vis spectroscopy. Then the J-V curve, electrochemical impedance spectroscopy (EIS), and open-circuit voltage decay (OCVD) measurement were applied to evaluate the photovoltaic performance of DSSCs. Compared with the commercial TiO2 nanoparticles (P25), the synthesized-TiO2 nanoparticles showed better performance. By adding diethylene glycol (DEG) before the hydrothermal process, the synthesized TiO2 nanoparticles (hereafter referred to as TiO2-DEG particles) shows narrower size distribution, larger specific surface area, higher crystallinity, and less surface defects than TiO2 (DEG free) particles. The analysis of photovoltaic properties of DSSCs based on TiO2-DEG particles showed that the recombination of electron-hole pairs was decreased and the trapping of carries in grain boundaries restrained. It was believed that the photoelectrode fabricated with the as-prepared TiO2 nanoparticles improved the loading amount of dye sensitizers (N719), and enhanced the photocurrent of the DSSCs. As a result, the TiO2-DEG particle based cells achieved a photo-to-electricity conversion efficiency (η) of 7.90%, which is higher than 7.53% for the cell based on TiO2 (DEG free) and 6.59% for the one fabricated with P25.Download high-res image (86KB)Download full-size imageThe TiO2-diethylene glycol (DEG) based dye-sensitized solar cells perform a noticeable improvement in the overall efficiency of maximum 7.90% which is higher than 7.53% for the cell made of TiO2 (DEG free) and 6.59% for the cell made of P25.

How to graft co-sensitizers with different binding strengths onto TiO2 surfaces for enhancing the performance of dye-sensitized solar cells (DSSCs) has not been discussed very much. Herein a ruthenium-based sensitizer (N719) and a porphyrin molecule (LP-2) with complementary absorption spectra (300–750 nm) have been chosen to investigate how the dye loading procedure would influence the photovoltaic performance of co-sensitized solar cells. Interestingly, it is found that 54.7% of the loading amounts of pre-adsorbed LP-2 are replaced by the post-adsorption of N719. The replacement adsorption is not observed when the two molecules are loaded in reverse order, which is attributed to their different adsorption configurations and binding energies. The competitive adsorption between co-sensitizers is thus systematically investigated by UV-visible absorption spectroscopy, energy dispersive spectrometry (EDS) and electron probe microanalysis (EPMA). Upon optimization, the device sequentially sensitized with LP-2 and N719 exhibits efficiency (7.72%) enhancement of 38.6% and 18.0% compared with those fabricated with single LP-2 and N719, respectively. The results provide a new vision on the stepwise sensitization of TiO2 films using co-sensitizers with a difference in adsorption properties, suggesting that complementary spectral absorption of co-sensitizers can lead to excellent cell performance by choosing an appropriate dye loading procedure.

The sintered TiO2 nanofilms were immersed in the aqueous solution of graphite oxide and then were thermally reduced to reduced graphene oxide (RGO), resulting in RGO-doped TiO2 photoanodes employed in the dye-sensitized solar cells (DSSCs). This preparation method for the reduced graphene oxide–TiO2 (RGO–TiO2) photoanode could avoid the loss of RGO during the sintering process. The presence of RGO in the photoanodes was confirmed using Raman analysis, scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectrometer. The amount of RGO in photoanode was obtained by thermo-gravimetric analysis. Other techniques such as X-ray diffraction, Brunauer–Emmett–Teller, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the composite materials of RGO–TiO2. The J–V measurement of RGO–TiO2-based DSSCs showed that the best photoelectric conversion efficiency (η) of 6.85% is 11.7% higher than that of the pure TiO2 (P25–TiO2)-based DSSCs. It was shown that RGO in the photoanode could facilitate the phase transition in TiO2 crystals (from anatase to rutile) resulting in the mixed crystals in the photoanodes. The existence of RGO and mixed-crystal structure of TiO2 changed the electronic transmission pathway, reduced the recombination rate of electron–hole pairs, and thus improved the η of DSSCs.

Three donor–π conjugated unit–acceptor (D–π–A) type zinc porphyrin sensitizers LX1, LX2 and LX3 bearing meso acrylic acid, α-cyanoacrylic acid, and α-cyanopentadienoic acid, respectively, as the π-bridged acceptors were designed and synthesized for use in dye-sensitized solar cells (DSCs). The interesting role of the cyano group attached to the α position of the acrylic and pentadienoic acid acceptor was investigated. It was shown that even though the introduction of the cyano group and the elongation of the π-bridge can both increase the light-harvesting as indicated by the UV-vis absorption spectra, the relevant cell performance dropped significantly. The photo to power conversion efficiencies (PCEs) of the devices increase in the order of LX1 > LX2 > LX3, with the highest PCE of 6.04% achieved for the LX1-based cell, which bears acrylic acid as the π-bridged acceptor. To further explore the effect of –CN and –CHCH– on the interaction between the absorbed dye and TiO2 substrates, their density of states (DOS) and partial density of states (PDOS), as well as electronic properties were investigated in detail using theoretical calculations. The results suggest that introducing the –CN group into the acceptor and extending the conjugation of the π-bridge have decreased the LUMO levels of the dyes, leading to weak interfacial coupling, low electron injection driving force, low Jsc, and thus poor cell performance.

We construct a simple-structured super gelator with multi-stimuli responsive properties, among which anion responsiveness follows the Hofmeister series in a non-aqueous system. Versatile applications such as being rheological and self-healing agents, waste water treatment, spilled oil recovery and flexible optical device manufacture are integrated into a single organogelator, which was rarely reported.

•Four boron dipyrromethene (BODIPY) type sensitizers were synthesized.•The BODIPY sensitizers contain triarylamine donors with different rigidities.•These BODIY dyes were applied in dye-sensitized solar cells (DSSCs).•The fluorescence quantum yield and lifetime influenced the cell performance.•The fluorescence quantum yield and lifetime related to molecules' rigidities.Four donor-π bridge-acceptor structured boron dipyrromethene type sensitizers bearing triarylamine donors with different rigidities were synthesized and applied in dye-sensitized solar cells. The influence of different triarylamine donors on the optical, electrochemical properties and photovoltaic performances of sensitizers was systematically investigated. It was shown that the photovoltaic performance of boron dipyrromethene type sensitizer-based cell increased with increasing the fluorescence quantum yield and fluorescence lifetime of the corresponding sensitizers, which are believed to be closely related to the rigidities of the donor groups in the molecule. The best performance was realized for the cell based on rigid 9-phenyl-carbazole-substituted boron dipyrromethene sensitizer (ZH-b) with a fluorescence quantum yield of 0.516 and a fluorescence lifetime of 4.02 ns, resulting in a short circuit photocurrent density of 14.10 mA/cm2 and an overall conversion efficiency of 4.42%, which are fairly good results achieved for boron dipyrromethene type sensitizer-based solar cell.

•Hydrophobic alkoxy chains in porphyrin influence the solar energy conversion efficiency.•Incorporation of long alkoxy chain is an efficient method to suppress dye aggregation.•The long alkoxy chain can also retard the charge recombination.•The longer length of the alkoxy chain, the smaller amount of dyes absorbed on TiO2.A series of novel zinc porphyrin dyes which are featured with a D–π–A structure have been designed and synthesized for use in dye-sensitized solar cells (DSSCs). The influences of different hydrophobic hydrocarbon chains (none, butoxy, octoxy groups) attached at the porphyrin meso-aryl group on the molecules’ photophysical and electrochemical properties, as well as on the photovoltaic performance of the corresponding DSSCs were investigated systematically. The best performance was realized for the cell sensitized with the porphyrin (LP-2) containing a n-butoxy chain on the meso-aryl group and with the acrylic acid as the acceptor. The optimized power conversion efficiency of LP-2 reaches 6.04% with an open-circuit voltage of 730 mV, a short-circuit current density of 11.67 mA cm−2, and a fill factor of 0.71.

With urea as nitrogen source, N-doped TiO2 powders were synthesized and fabricated for low-temperature dye-sensitized solar cells (DSSCs) by the method of doctor-blade, and the highest temperature of the whole process was 120 °C. SEM, TEM, XRD, DRS, and XPS were used to analyze the microstructure of the N-doped TiO2 powders. EIS, Bode plot, UV–Vis and I–V were employed to measure the photovoltaic performance of the DSSCs. The maximum photoelectric conversion efficiency (η) was 5.18 % when the amount of the doped nitrogen was 4 %, and, when compared with the η of 4.22 % for pure TiO2, the short circuit current was increased by 22.2 % and the efficiency was increased by 22.7 %. It has been shown that the doped nitrogen could effectively suppress TiO2 crystal phase transition from anatase to rutile, and decrease the size of particles. Therefore, the increased photoelectric conversion efficiency of the N-doped TiO2-based DSSC was ascribed to the more suitable crystal phase, sizes and inner structure.

•Different diarylamino substituents have different electron donating abilities.•The porphyrin meso diarylamino substituent has a significant influence on the overall solar energy conversion efficiency.•Fukui function has been employed to evaluate nucleophilicities and electron-donating abilities of amino nitrogen.A series of novel zinc porphyrins which are featured with a donor–π–acceptor structure have been synthesized for use in the dye-sensitized solar cells. Various diarylamine moiety, such as diphenylamine, iminodibenzyl or iminostilbene, is introduced at porphyrin meso position as an electron donating group. The cell fabricated with the iminodibenzyl-substituted porphyrin sensitizer yields a short circuit photocurrent density of 9.68 mA/cm2, an open-circuit voltage of 740 mV, and a fill factor of 73.48%, corresponding to an overall conversion efficiency (η) up to 5.26%, which is greater than those obtained by diphenylamine- and iminostilbene-substituted porphyrin-sensitized solar cells (η = 4.05% and 2.62%, respectively). The theoretical studies reveal that the iminodibenzyl donor has the strongest electron donating ability among all three diarylamine substituents employed, which is believed to play a significant role in influencing the photovoltaic properties of these sensitizer-based solar cells.

A series of D–π–A zinc porphyrin sensitizers Dye1–Dye6 bearing a substituted iminodibenzyl group at the porphyrin meso position, which is expected to have different electron-donating abilities, were designed. Theoretical studies were performed to examine the photovoltaic properties of these molecules in dye-sensitized solar cells (DSSCs). In particular, the important concepts, the Fukui function and the extended condensed Fukui function, are employed to describe the electron-donating abilities accurately at the quantitative level. Tangui Le Bahers model was adopted to analyze charge transfer (CT) during electron transition. A correlation between the electron donating abilities of the derived iminodibenzyl group and CT was built to evaluate the cell performance based on sensitizers Dye1–Dye6. The theoretical studies showed that porphyrins Dye1–Dye3 bearing an extremely strong electron-donating group (EDG) would fail in the generation of photocurrent in the closed circuit when applied in DSSCs due to the higher level of the HOMO energy than the redox potential of the redox couple (I−/I3−). The one with a weaker EDG (Dye4) is expected to show better photovoltaic performance than porphyrin IDB with an unsubstituted iminodibenzyl group. This study demonstrates a reliable method involving the employment of the Fukui function, the extended condensed Fukui function and the Tangui Le Bahers model for the evaluation of newly designed D–π–A type porphyrin sensitizers for use in DSSCs, and as guidance for future molecular design.

Three-dimensional (3D) ZnO nanoaggregates with different morphologies and sizes were fabricated by the hydrothermal method, including cauliflower-like microspheres with an average diameter of 1–2 μm, nano-sheet aggregated safflower-like microspheres with 3–4 μm and ixora-like nano-structures with 500–600 nm. We found that their morphology formation was dependent on the concentration of OH− and construction agent (glutamic acid) during the synthesis process, based on which we proposed the mechanism for the formation of ZnO nanoaggregates. The studies showed that, the photo to current conversion efficiencies (PCEs) of the dye-sensitized solar cells (DSSCs) in which the photoanodes were fabricated using the prepared 3D ZnO nanoaggregates were all higher than those obtained employing the ZnO nanoparticles (NPs). In particular, the PCE of the DSSC based on the cauliflower-like ZnO photoanode (4.52%) was about 21% higher than that fabricated with the ZnO NP-based photoanode. This can be attributed to the higher specific surface area of the cauliflower-like ZnO photoanode leading to a greater amount of dye adsorption, more suitable size for light scattering and better inner connection for the transportation of electrons. Moreover, when these 3D ZnO nanoaggregates were used as the scattering layers in the P25-based photoanode in DSSCs, higher PCE of up to 6.74% was achieved, compared to 5.37% obtained for the DSSC without a scattering layer.

Several mesoporous TiO2 (MT) materials were synthesized under different conditions following a hydrothermal procedure using poly(ethylene-glycol)-block-poly(propylene-glycol)-block-poly(ethylene-glycol) (P123) as the template and titanium isopropoxide as the titanium source. The molar ratios of Ti/P123, and the pH values of the reaction solution in an autoclave were investigated. Various techniques such as Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), laser Raman spectrometry (LRS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) were used to characterize the products. Then, these materials were assembled into dye-sensitized solar cells (DSSCs). Analysis of the J–V curves and electrochemical impedance spectroscopy (EIS) were applied to characterize the cells. The results indicated that the specific surface area and crystalline structure of these materials provide the possibility of high photocurrent for the cells, and that the structural characteristics of the specimens led to increased electron transfer resistance of the cells, which was beneficial for the improvement of the photovoltage of the DSSCs. The highest photoelectric conversion efficiency of the cells involving MT materials reached 8.33%, which, compared with that of P25-based solar cell (5.88%), increased by 41.7%.

•Polystyrene (PS) microspheres were used to fabricate films with different pore sizes.•Flims with different pore sizes were obtained by burning out varying amount of PS.•The photoelectrode with appropriate pore size had optimum performance.•A hierarchical TiO2 photoelectrode with pore size gradually increasing was prepared.•The hierarchical TiO2 photoelectrode had best photoelectric conversion efficiency.The TiO2 photoelectrode containing pores of different sizes was fabricated by adding various amounts of polystyrene microspheres (188 nm) into the TiO2 paste, which was used as template agent during the sintering process. On the one hand, it was found that the photoelectrode with appropriate size of pores was beneficial for the enhancement of photovoltaic performance of the corresponding dye-sensitized solar cells (DSSCs) via efficient utilization of incident light. On the other hand, the presence of large pores would also tend to reduce the amount of dye-uptake resulting in the decrease of cell performance. Furthermore, a multi-layered stacking architecture of TiO2 nanoporous film with pore size gradually increased from bottom FTO glass to the top of the film was developed and used as photoelectrode in DSSCs with N719 as the sensitizer. The photoelectric conversion efficiency of 7.80% was realized which is 17.6% higher than that obtained for DSSCs containing TiO2 nanoporous films with uniform size of pores. UV–vis spectra measurement and electrochemical impedance spectroscopy analysis were carried out for further studying the effect of the pore size and the stacking pattern on the photoelctronic and electrochemical properties of the resultant DSSCs.

Three corrole–fullerene dyads were prepared by treating anthracene-functionalized corroles with fullerene. Their structures were characterized by 1D- and 2D-NMR spectra and mass spectra. In the preliminary photo physical study of 3a by fluorescence spectroscopy, the excited corrole unit was quenched due to the introduction of fullerene. TD-DFT calculation theoretically indicated that the electron transfer occurs from the excited corrole to fullerene.

A series of novel zinc porphyrin dyes which have a D–π–A structure have been designed and synthesized for DSSC applications. The donors containing a carbazole group in which the carbazole nitrogen is bonded with a butyl, hexyl or decyl chain, had a significant influence on the spectra of the TiO2 films and the electrochemical and photovoltaic properties of these sensitizers. The sensitizer with a hexyl chain (CZ-6) achieved a higher overall conversion efficiency than that with a butyl chain (CZ-4) because of its slower charge recombination rate and faster electron injection from the dye to the conduction band of the conducting glass. Furthermore, the dye with a decyl chain (CZ-10) performed the lowest conversion efficiency, resulting from the least amount of dye loading. This was due to the steric hindrance of the molecule. The highest light-to-electricity conversion efficiency (η) of 2.13% was realized for the dye CZ-6 based DSSC, which was higher than those achieved for the CZ-4- and CZ-6-sensitized DSSCs (1.69% and 1.30% respectively).

•Yellow particles coated with polyethylene (PE) and polystyrene (PS) were prepared.•Yellow and white particles were dispersed in a mixed dielectric solvent.•A chromatic display cell consisting of yellow particles was successfully fabricated.•The greatest contrast ratio of 1.48 was realized, as well as a response time of 2 s.C.I. Pigment Yellow 181 (PY181) composite particles encapsulated by polyethylene (PE) were prepared by dispersion polymerization method, and C.I. Pigment Yellow 110 (PY110) composite particles encapsulated by polystyrene (PS) with mini-emulsion polymerization method were achieved, respectively. The modified pigments were characterized by fourier transform infrared spectroscopy, scanning electron microscope and transmission electron microscope. Compared with the PE-coated PY 181 pigments, the PS-coated PY-110 particles had a narrow particle size distribution, regular spherical and average particle size of 450 nm. Suspension 1 and suspension 3 were prepared by the two composite particles dispersed in isopar M. A chromatic electrophoretic display cell consisting of yellow particles was successfully fabricated using dispersions of yellow ink particles in a mixed dielectric solvent with white particles as contrast. The response behavior and the contrast ratio to the electric voltage were also examined. The contrast ratio of pigments modified by polystyrene was 1.48, as well as the response time was 2 s, which were better than those of pigments modified by polyethylene.

A series of experiments were designed to understand the effects of substituent and solvent on the Sonogashira coupling reaction of β-bromoporphyrin using a Pd2(dba)3/AsPh3 system as the catalyst. Electron-efficient groups and aprotic solvents are conducive to the reaction. A possible explanation was given. A new family of β-pyrrole substituted porphyrins was also synthesized during the study.

Monobromination of β, β′-π-extended porphyrins was found to selectively occur at the β or β′ position of the porphyrins which is antipodal to the fused aromatic ring. Subsequent Sonogashira or Heck coupling of the resultant bromoporphyrin introduced a carboxylphenylethynyl group or an acrylic acid group to the π-extended porphyrin. The optimal reaction conditions were found for the Sonogashira and Heck coupling reaction. All of the coupling products have shown a broadening and red-shift of the Soret band and Q bands in the UV–Vis absorption spectra compared with the π-extended porphyrin starting materials and the original unmodified porphyrins.

Four simple trans-AB-porphyrins 3a–3d either without any alkoxyl substituent, or with a mono-alkoxyl chain at different (ortho and para) positions of the meso-phenyl ring, or with two alkoxyl chains at two ortho positions of the meso-phenyl ring were designed and synthesized via three steps. The synthesis is simple and no expensive metal catalyst is involved. All compounds were characterized by 1H-NMR and mass spectraometry. UV-Vis absorption spectra and B band-excited fluorescence emission spectra were also obtained. The synthesized porphyrins were applied in dye-sensitized solar cells (DSSCs). Up to 3.05% conversion efficiency was realized for 3d under our experimental conditions, attributed to the two long alkoxyl chains present at the ortho positions of the meso-phenyl group. The influences of the position and the number of the alkoxyl chains at the macrocyclic meso-phenyl group on the photovoltaic performance of DSSCs are well explained via DFT calculations. It was shown that the VOC and JSC of the sensitizers are determined by μnormal, ΔGinject and LHE.

Four π-extended, β,β′ aromatic ring fused porphyrins including mono- and opp-dibenzoporphyrins bearing two carboxyl groups at only one fused benzo group were synthesized. The optical results by UV–vis spectroscopy indicate that when compared with the absorption spectra of monobenzoporphyrins, greater light-harvesting capabilities can be realized for opp-dibenzoporphyrins with two benzo group at the opposite β,β′ positions of the porphyrin. The photovoltaic properties of these π-extended porphyrins were examined for the first time and the highest conversion efficiency of 1.62% was realized for opp-dibenzoporphyrin 8a-sensitized solar cell, which is ∼60% higher than that of monobenzoporphyrin 4a based solar cell indicating the effect of an extra aromatic π conjugation on the light-harvesting capabilities of π-extended porphyrins. Subsequent DFT calculation results supported our results obtained in the optical and photovoltaic studies.

•D–A–π–A type dyes with benzoselenadiazole (BSD) auxiliary acceptor are synthesized.•Using phenyl as π spacer here and coadsorbent could help to improve cells' Jsc and Voc.•BSD proved to be a promising electron-withdrawing acceptor for D–A–π–A sensitizers.Three new D–A–π–A configuration organic dyes (LC-6, LC-7 and LC-8) based on triphenylamine as the electron donor, benzoselenadiazole (BSD) as the auxiliary acceptor, either thiophene or benzene as the π spacer and cyanoacetic acid as the anchoring group have been designed and synthesized for dye-sensitized solar cells (DSCs). Introduction of octyloxy chain on the triphenylamine unit was found to be able to redshift the absorption spectra and suppress the charge recombination. It was also found that using the benzene instead of thiophene as π spacers and using CDCA coadsorbent could help to improve the Jsc and Voc values of the cell. Under standard global AM 1.5 solar light conditions, a DSC employing a dye with a 1,4-phenylene unit with CDCA gave the best photovoltaic performance with a Jsc of 13.21 mA cm−2, a Voc of 734 mV, a FF of 0.69 and an overall PCE of 6.72%. These results suggest that the BSD unit can be a promising electron-withdrawing candidate in D–A–π–A type sensitizers for further exploration DSCs.

A series of D–π–A zinc porphyrin sensitizers Dye1–Dye6 bearing a substituted iminodibenzyl group at the porphyrin meso position, which is expected to have different electron-donating abilities, were designed. Theoretical studies were performed to examine the photovoltaic properties of these molecules in dye-sensitized solar cells (DSSCs). In particular, the important concepts, the Fukui function and the extended condensed Fukui function, are employed to describe the electron-donating abilities accurately at the quantitative level. Tangui Le Bahers model was adopted to analyze charge transfer (CT) during electron transition. A correlation between the electron donating abilities of the derived iminodibenzyl group and CT was built to evaluate the cell performance based on sensitizers Dye1–Dye6. The theoretical studies showed that porphyrins Dye1–Dye3 bearing an extremely strong electron-donating group (EDG) would fail in the generation of photocurrent in the closed circuit when applied in DSSCs due to the higher level of the HOMO energy than the redox potential of the redox couple (I−/I3−). The one with a weaker EDG (Dye4) is expected to show better photovoltaic performance than porphyrin IDB with an unsubstituted iminodibenzyl group. This study demonstrates a reliable method involving the employment of the Fukui function, the extended condensed Fukui function and the Tangui Le Bahers model for the evaluation of newly designed D–π–A type porphyrin sensitizers for use in DSSCs, and as guidance for future molecular design.

We construct a simple-structured super gelator with multi-stimuli responsive properties, among which anion responsiveness follows the Hofmeister series in a non-aqueous system. Versatile applications such as being rheological and self-healing agents, waste water treatment, spilled oil recovery and flexible optical device manufacture are integrated into a single organogelator, which was rarely reported.

A novel two-component organogel system based on acid–base interaction showed flexibility, high-transparency and self-healing properties with enhanced viscoelasticity. Meanwhile, the two-component gelator displayed room-temperature phase selective gelation of aromatic solvents from aromatic solvents/water mixtures in powder form and excellent dye removal ability.

The development of efficient catalysts with a visible-light response is of great importance in photocatalysis. Porphyrinic metal-organic frameworks (porph-MOFs) have recently been shown as promising photocatalyst candidates due to their large surface area, high visible light harvesting efficiency, and semiconductive properties, but challenges still remain because of their rapid charge recombination. Herein, we report the design of an effectively visible-light-driven composite material, namely TP-222(Zn), containing zirconium-based porph-MOF PCN-222(Zn) linked TiO2 nanoparticles (NPs) via the compound 4-mercaptopyridine which is axially bonded to the porphyrin central Zn metal in the PCN-222(Zn) and anchored onto the surface of TiO2 NPs. The resulting composite material demonstrates the high dispersion of TiO2 NPs and their close contact with the porph-MOF matrix, and serves as an effective photocatalyst for degrading organic contaminants under visible light irradiation due to their synergistic effect. It is further confirmed by fluorescence spectroscopy and electrochemical impedance spectroscopy that the remarkably enhanced photocatalytic activity of the TP-222(Zn) composite is attributed to the efficient charge separation with electron injection from PCN-222(Zn) to TiO2 NPs. In addition, the TP-222(Zn) composite shows excellent stability and recyclability as a result of the axially coordinative interaction between TiO2 NPs/PCN-222(Zn) and the 4-mercaptopyridine. Overall, this work provides a new strategy for the fabrication of highly efficient porph-MOF-based composite materials for visible light-driven photocatalysis.