Co-reporter:Ning Jia, Shanpeng Wang, Zeliang Gao, Qian Wu, Chunlong Li, Xixia Zhang, TongTong Yu, Qingming Lu, and Xutang Tao
Crystal Growth & Design November 1, 2017 Volume 17(Issue 11) pp:5875-5875
Publication Date(Web):October 2, 2017
DOI:10.1021/acs.cgd.7b00964
Single crystals of an environmental friendly material LiInSe2 (LISe) with dimensions up to Φ16 mm × 55 mm were grown successfully through a modified vertical Bridgman technique. The quality of the crystal was measured by a high resolution X-ray diffraction rocking curve, and a full width at half-maximum (fwhm) for a, b, and c faces are 47″, 46″, 36″, respectively. It indicates that the as-grown crystal is high quality. The complete sets of dielectric, elastic, and piezoelectric constants of LISe crystals at room temperature were obtained by the resonant technique and impedance analysis for the first time. The piezoelectric constants d24 and d33 reached −13.6 pC/N and 8.5 pC/N, respectively. The corresponding electromechanical coupling coefficient k33 is 21%. In addition, the structural distortions and dipole moments of LISe were analyzed in detail. Our results show that LISe is a promising candidate as an environmental friendly piezoelectric material.
Co-reporter:Dianxing Ju;Tianyu Zhao;Dang Yangyang;Guodong Zhang;Xiaobo Hu;Deliang Cui;Xutang Tao
Journal of Materials Chemistry A 2017 vol. 5(Issue 41) pp:21919-21925
Publication Date(Web):2017/10/24
DOI:10.1039/C7TA07413A
The desired morphology, narrowed band gap and good photoelectric properties are the key factors for achieving the wide application of hybrid perovskite materials. During the preparation of novel hybrid perovskite materials, preserving the morphology of highly crystalline materials and narrowing their band gap will be desirable for designing photoelectric devices with outstanding performance. Here, with broad band gap 1D/2D hybrid perovskite single crystals as a template, we design a universal conversion process from single crystal to single crystal for a variety of large-sized hybrid perovskite materials induced by CH3NH2 (MA) gas under an ambient atmosphere. Most significantly, the hybrid perovskite single crystals keep their original morphology, narrow their optical band gap, and enhance their carrier mobility and photo-response dramatically after induced conversion by MA gas molecules, especially for DMAPbI3 (NH2(CH3)2PbI3). The optical band gap of DMAPbI3 was lowered from 2.58 eV to 1.53 eV and its photo-response performance was enhanced greatly by even a small amount of replacement of DMA+ by MA+, which provides a new idea for designing novel hybrid perovskite single crystals with a desired morphology and their optoelectronic devices with good performance.
Co-reporter:Peng Zhao;Qian Wu;Zeliang Gao;Xiangxin Tian;Conggang Li;Youxuan Sun;Chengqian Zhang;Shengqing Xia;Xutang Tao
RSC Advances (2011-Present) 2017 vol. 7(Issue 8) pp:4278-4284
Publication Date(Web):2017/01/10
DOI:10.1039/C6RA26776A
In this study, Cs2TeW3O12 (CTW) single crystals were grown successfully through a top-seeded solution growth (TSSG) method using TeO2 as a self-flux. We identified a complete set of growth process parameters suitable for facilitating the growth of a high-quality CTW crystal. The results indicate that, in the same thermal field and with an appropriate flux ratio, a smaller cooling rate of the melt facilitates the smooth growth of high-quality CTW single crystals. The melt-viscosity versus temperature curves for different flux ratios were measured, and their effects on the crystal quality were discussed. In addition, the morphology of the crystal can be controlled by adjusting the rotation speed and the orientation of the seed. To investigate piezoelectric performance, complete sets of dielectric, elastic, and piezoelectric coefficients of CTW crystals were measured using both resonance and impedance analysis. The piezoelectric coefficients d33 and d15 reached 19.1 pC N−1 and 25.9 pC N−1, respectively. The electromechanical coupling coefficient, k33, was 37.7%, slightly higher than that of Cs2TeMo3O12 (CTM). Furthermore, the extent of dipole moment and polyhedron distortion of the CTW crystal were analysed in detail, and the relationship between the crystal structure and the piezoelectric properties was also discussed.
Co-reporter:Wenxiang Mu;Yanru Yin;Zhitai Jia;Lijuan Wang;Jie Sun;Mengxia Wang;Cheng Tang;Qiangqiang Hu;Zeliang Gao;Jian Zhang;Na Lin;Stefano Veronesi;Zhengping Wang;Xian Zhao;Xutang Tao
RSC Advances (2011-Present) 2017 vol. 7(Issue 35) pp:21815-21819
Publication Date(Web):2017/04/18
DOI:10.1039/C7RA01905J
Considering their easy growth and doping in bulk crystal growth, and good crystalline quality, β-Ga2O3 single crystals, a very important wide-bandgap semiconductor, are now also considered to be a promising optical crystal candidate. In this work, a Cr4+:β-Ga2O3 single crystal has been grown successfully by the edge-defined film-fed growth method. The thermal conductivity of Cr4+:β-Ga2O3 has been measured along the a* direction at room temperature obtaining 16.2 W m−1 K−1, and it was much larger than that of the usually used Cr4+-doped crystals, such as Y3Al5O12 (YAG) or YVO4. The Raman spectrum indicated that the cutoff phonon energy of the β-Ga2O3 crystal was 767.8 cm−1. A passively Q-switched nanosecond pulsed Nd:YAG laser based on a Cr4+:β-Ga2O3 saturable absorber was experimentally demonstrated for the first time to our knowledge and its mechanism is explained by first-principles calculations. By inserting the Cr4+:β-Ga2O3 crystal into the Nd:YAG laser cavity, a Q-switched laser operation was obtained with a maximum average output power of 50 mW. The corresponding pulse repetition rate, pulse width, and pulse energy were determined to be of 421.5 kHz, 235.2 ns and 0.12 μJ, respectively.
Co-reporter:Tongtong Yu;Shanpeng Wang;Huapeng Ruan;Chunlong Li;Xixia Zhang;Ning Jia;Jian Zhang;Xutang Tao
RSC Advances (2011-Present) 2017 vol. 7(Issue 76) pp:47938-47944
Publication Date(Web):2017/10/11
DOI:10.1039/C7RA08118A
Herein, a single crystal of FeSi4P4 (FSP) with dimensions up to 8 × 7 × 3 mm3 was successfully grown using a seeded flux growth method. Single crystal X-ray diffraction results revealed that the FSP crystal crystallized in the chiral space group P1 (no. 1). High-resolution X-ray diffraction presents a full-width at half-maximum (FWHM) of 36′′ and 46′′ for the (100) and (001) FSP crystals, respectively, which indicates that FSP crystals have high crystalline quality. FSP is thermally stable up to 1157.1 °C and has a high thermal conductivity of 35 W (m K)−1 at room temperature. The magnetic analysis shows that the FSP crystal is paramagnetic in the range from 5 to 300 K. The Hall effect measurement suggests that the FSP crystal is a promising p-type semiconductor at room temperature.
Co-reporter:Chunlong Li;Shanpeng Wang;Xixia Zhang;Ning Jia;Tongtong Yu;Min Zhu;Duo Liu;Xutang Tao
CrystEngComm (1999-Present) 2017 vol. 19(Issue 46) pp:6986-6991
Publication Date(Web):2017/11/27
DOI:10.1039/C7CE01676J
Two-dimensional (2D) materials have recently attracted great interest due to their promising optoelectronic applications. Orthorhombic SiP (o-SiP) is a 2D layered crystal and may have a significant impact on optoelectronic technologies. Large-sized bulk o-SiP single crystals have been successfully grown by a seeded flux method. The size and morphology of o-SiP crystals can be controlled by changing the growth conditions. The carrier mobility and band gap of o-SiP were characterized in detail. The photoresponse properties of o-SiP were investigated and a relatively fast response has been demonstrated. The experimental results indicate that o-SiP may be an excellent candidate for applications in electronics and optoelectronics.
Co-reporter:Dianxing Ju;Tianyu Zhao;Yangyang Dang;Guodong Zhang;Xiaobo Hu;Deliang Cui;Xutang Tao
Journal of Materials Chemistry A 2017 vol. 5(Issue 45) pp:24014-24014
Publication Date(Web):2017/11/21
DOI:10.1039/C7TA90247F
Correction for ‘Gas induced conversion of hybrid perovskite single crystal to single crystal for great enhancement of their photoelectric properties’ by Dianxing Ju et al., J. Mater. Chem. A, 2017, DOI: 10.1039/c7ta07413a.
Co-reporter:Dianxing Ju;Tianyu Zhao;Yangyang Dang;Guodong Zhang;Xiaobo Hu;Deliang Cui;Xutang Tao
Journal of Materials Chemistry A 2017 vol. 5(Issue 45) pp:24014-24014
Publication Date(Web):2017/11/21
DOI:10.1039/C7TA90247F
Correction for ‘Gas induced conversion of hybrid perovskite single crystal to single crystal for great enhancement of their photoelectric properties’ by Dianxing Ju et al., J. Mater. Chem. A, 2017, DOI: 10.1039/c7ta07413a.
Co-reporter:Ci Wang;Jie Sun;Huiyang Gou;Shanpeng Wang;Jian Zhang;Xutang Tao
Physical Chemistry Chemical Physics 2017 vol. 19(Issue 14) pp:9558-9565
Publication Date(Web):2017/04/05
DOI:10.1039/C7CP01312D
In view of their high nonlinear optical coefficients and good phase-matching properties, CdSiP2 (CSP) crystals are considered as one of the most promising materials in the field of nonlinear optical applications. However, the slight absorption losses around 1.34 μm and 1.78 μm under e-polarized light have been affecting its performance. In this study, first-principles calculations were performed to identify the effects of various charge defects on the absorption properties. Different intrinsic defects in the CSP crystal were calculated using the HSE method and compared according to the specific chemical environments in the experiments. The results show that the point defects of V2−Cd, Si2+Cd, and V4−Si, which can be spontaneously formed, are dominant in the Cd-poor environment. The combination of Si2+Cd and V2−Cd defects is the most favorable cluster in the Cd-poor case because of its relatively low formation energy. Furthermore, the antisite defect SiCd was found to be responsible for the main absorption peaks at 1.34 and 1.78 μm in the experimental spectra, whereas other defects and clusters, such as the defects Si2+Cd and V0Si, also contribute to these red shifted absorptions. Our results intend to provide a guideline for adjusting the optical absorption in CSP by modifying its defects.
Co-reporter:Qiangqiang Hu;Zhitai Jia;Cheng Tang;Na Lin;Jian Zhang;Ning Jia;Shanpeng Wang;Xian Zhao;Xutang Tao
CrystEngComm (1999-Present) 2017 vol. 19(Issue 3) pp:537-545
Publication Date(Web):2017/01/16
DOI:10.1039/C6CE02411D
CaGdAlO4 (CGA) single crystals have been grown in different oxygen concentration atmospheres by the Czochralski method. Crystals grown under an oxygen-containing atmosphere presented an inconsistent brown coloration. The origin of coloration was studied by density functional theory, and the simulated results show the oxygen defects and the absorption matched well with the experimental results. The brown coloration of CGA is due to the interstitial oxygen atoms. The fundamental properties of CGA crystals with different colors, including the crystal density, hardness, thermal and optical properties, were systematically investigated and compared when taking into account the effect of color center inside. The colorless CGA was grown under an inert gas atmosphere and exhibits a wide transparency range of 227–7140 nm. The maximum phonon energy was determined to be as low as 618 cm−1. The colorless CGA host crystal with a disordered structure, good thermal conductivity, low maximum phonon energy and wide transparency is promising for ultrafast ultraviolet and visible laser applications.
Co-reporter:Qiangqiang Hu;Zhitai Jia;Azzurra Volpi;Stefano Veronesi;Mauro Tonelli;Xutang Tao
CrystEngComm (1999-Present) 2017 vol. 19(Issue 12) pp:1643-1647
Publication Date(Web):2017/03/20
DOI:10.1039/C7CE00019G
Yb:CaLuxGd1−xAlO4 (Yb:CLGA) crystals have been grown and studied for the first time. A more disordered structure than that of the Yb:CaGdAlO4 (Yb:CGA) crystal was designed by introducing Lu3+ ions into the crystal. The absorption spectra at 9.6 K provided clear evidence for the disordered structure of the Yb:CLGA crystal. Moreover, further spectral broadening was achieved compared to that of the Yb:CGA crystal. The crystal quality and spectroscopic properties of the Yb:CLGA crystal with the highest degree of disorder were investigated in detail. Improved ultrafast laser oscillators, in terms of narrower pulse width and higher peak power, are expected with this modified crystal.
Co-reporter:Wenxiang Mu;Zhitai Jia;Yanru Yin;Qiangqiang Hu;Jian Zhang;Qian Feng;Yue Hao;Xutang Tao
CrystEngComm (1999-Present) 2017 vol. 19(Issue 34) pp:5122-5127
Publication Date(Web):2017/08/31
DOI:10.1039/C7CE01076A
High-quality bulk β-Ga2O3 single crystals have been grown by optimized edge-defined film-fed growth (EFG) method. The problems of cracking and polycrystals have been effectively solved by using a high-quality 1 inch-wide seed. The crystalline quality of the as-grown crystal has been confirmed by X-ray rocking curve with a full-width at half-maximum (FWHM) of 42.1 arcsec. Moreover, an economical and efficient one-step mechanical exfoliation method has been proposed to get epi-ready β-Ga2O3 wafers directly. The root mean square (RMS) roughness of the wafers is noted to be around 0.1 nm, which means they are comparable or even better than wafers processed by chemical mechanical polishing (CMP). The mechanism of the exfoliation method is analyzed from a crystallographic view. A photodetector is fabricated on the exfoliated wafer directly and the device is proved to show good performance in solar-blind band.
Co-reporter:Chunxue Yuan, He Xi, Xutang Tao
Inorganic Chemistry Communications 2017 Volume 86(Volume 86) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.inoche.2017.10.009
An organic-inorganic hybrid solid (DMDP)[Hg(SCN)4] (1) (DMDP = 2,8-(6H,12H-5,11-methanodibenzo[b,f]diazocineylene)-di(p-ethenyl-N-methyl-pyridinium)) was designed and synthesized. X-Ray structural analysis reveals that it comprises a 3-D interpenetrating superstructure that 1-D inorganic anionic chains {[Hg(SCN)4]2 −}∞ penetrates into 2-D organic (DMDP)2 + cationic network. Photoluminescence investigation show that compound 1 exhibits a typical aggregation-induced emission (AIE) properties.A new organic-inorganic hybrid solid (DMDP)[Hg(SCN)4] based on Tröger's Base was designed and synthesized. Its crystal structure shows interesting interpenetrating architecture that 1-D inorganic anionic chains {[Hg(SCN)4]2-}∞ penetrates into 2-D organic (DMDP)2 + cationic network. The compound exhibits a typical aggregation-induced emission (AIE) property.Download high-res image (227KB)Download full-size image
Co-reporter:Wenxiang Mu, Zhitai Jia, Yanru Yin, Qiangqiang Hu, Yang Li, Baiyi Wu, Jian Zhang, Xutang Tao
Journal of Alloys and Compounds 2017 Volume 714(Volume 714) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.jallcom.2017.04.185
•High quality β-Ga2O3 crystal was grown by optimized EFG method.•Anisotropic thermal conductivities were measured to 500 °C for the first time.•Thermal transport of β-Ga2O3 was determined to be mainly depend on phonons.•Anisotropic refractive index and hardness were investigated.•Al was found to be a good Ohimc electrode for n-type β-Ga2O3.β-Ga2O3 is an ultra wide-bandgap semiconductor with promising applications in high voltage and temperature electronic devices and deep-ultraviolet optoelectronic devices, and has attracted lots of attention recently. However, there are still many unknowns about the basic properties needed to be explored urgently, which are very important and necessary for the devices design and application. In this work, bulk β-Ga2O3 single crystals with a width of 1 inch were grown by using an optimized edge-defined film-fed growth (EFG) method under Ar plus 50% CO2 atmosphere. High crystalline quality of the as grown crystal has been demonstrated by the high-resolution X-ray diffraction with 43.2 arcsec of the full width at half maximum (FWHM). The fundamental physical properties of different orientated samples, including thermal properties as a function of temperature up to 500 °C, electrical properties, refractive index and hardness were investigated systematically. Moreover, the measurement showed that aluminum turned out to be a good Ohimc electrode for n-type β-Ga2O3 single crystal.Download high-res image (320KB)Download full-size image
Co-reporter:Wenxiang Mu, Zhitai Jia, Yanru Yin, Qiangqiang Hu, Yang Li, Xutang Tao
Journal of Crystal Growth 2017 Volume 478(Volume 478) pp:
Publication Date(Web):15 November 2017
DOI:10.1016/j.jcrysgro.2017.08.007
•High quality Nd:LGGG crystal was grown by optimized EFG method for the first time.•The distribution of Nd3+ in the as-grown crystal was homogeneous.•The FWHM of rocking curve was as small as 32 arcsec.•The Ga2O3 evaporation was depressed efficiently by using an Ir lid.Device-size Nd3+:(LuxGd1−x)3Ga5O12 (Nd:LGGG) single crystal plates have been grown by edge-defined film-fed growth (EFG) method for the first time. The problems encountered during the crystal growth have been discussed and solved, resulting in a single crystal plate with a length of 180 mm. In particular, the evaporation loss of Ga2O3 composition during the crystal growing has been depressed efficiently by using an Ir lid. The crystal perfection was confirmed by X-ray rocking curve with a FWHM of the 32 arcsec, meaning a high crystalline quality. It was very interesting to find that the distribution of Nd3+ in the crystal grown by EFG method was more homogeneous than that in Cz method, benefitting from the larger segregation coefficient of Nd3+ in EFG method. The thermal conductivity was measured to be 8.1 W m−1 K−1 at room temperature. All the properties showed that the Nd:LGGG crystal plates grown by EFG method were promising for high power laser application.
Co-reporter:Guodong Zhang, Lei Wei, Longzhen Zhang, Xuping Wang, Bing Liu, Xian Zhao, Xutang Tao
Journal of Crystal Growth 2017 Volume 473(Volume 473) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.jcrysgro.2017.03.042
•Large crack-free CdSiP2 single crystal was grown by vertical Bridgman method.•Vibration properties of CdSiP2 were studied in experiment and theory.•High phonon frequencies arise from lighter atoms Si or PSi bonds.•Lower frequencies arise from the heavier atoms Cd or PCd bonds.Large crack free single crystals of CdSiP2 with the dimension of 40 mm in length and 8 mm in diameter were grown by vertical Bridgman method. The bonds vibration properties of the CdSiP2 single crystal were investigated by means of polarized micro-Raman spectroscopy and ab initio calculations. The Raman-active modes and IR-active modes were selected in turn. They were definitively assigned in wave number and symmetry based on classical lattice dynamics calculations. The results indicate that the high phonon frequencies mainly arise from the atomic vibrations of the lighter atoms Si or benching/stretching vibrations of PSi bonds; while, the lower frequencies mainly arise from the atomic vibrations of the heaver atoms Cd or the benching/stretching vibrations of PCd bonds. The conclusions may apply to other II–IV–V2 chalcopyrite compounds such as ZnGeP2, CdGeP2, ZnSiP2.
Co-reporter:Xiaoxin Zheng, Yang Liu, Guangfeng Liu, Jie Liu, Xin Ye, Quanxiang Han, Chao Ge, and Xutang Tao
Chemistry of Materials 2016 Volume 28(Issue 12) pp:4421
Publication Date(Web):May 19, 2016
DOI:10.1021/acs.chemmater.6b01622
Mixed halide coordination has been widely used to finely tune the properties of inorganic and inorganic–organic hybrid compounds, especially for emerging perovskites materials. Despite the increasing number of reports on preparation methods and the affected functionalities, the peculiar and precise role of the doping halogens in structural regulation of the crystals and the resulting variations on the basic properties remain to be addressed. Here, to shed light into the “black box”, a new series of [NH2(CH2CH3)2]3Bi(Cl1–xBrx)6 (x = 0, 0.135, 0.255, 0.385, 0.847, and 1) single crystals were grown from the mixed halide solvents by the temperature lowering method. The correlation between the inclusion amounts of Br in the final crystals with the halide concentrations in the precursors is discussed from different perspectives. The two kinds of halogens share the same position in the mixed halide system, with every crystallographically independent halide site possessing different halogen occupancies. The mixed halide coordination exhibits a regulated effect on the distortion of the anion octahedra. Optical absorption, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and the second harmonic generation (SHG) measurements have confirmed that, with increased Br inclusion, [NH2(CH2CH3)2]3Bi(Cl1–xBrx)6 crystals exhibit a regulated effect on their bandgaps, thermal stabilities, and SHG capacities.
Co-reporter:Yangyang Dang, Cheng Zhong, Guodong Zhang, Dianxing Ju, Lei Wang, Shengqing Xia, Haibing Xia, and Xutang Tao
Chemistry of Materials 2016 Volume 28(Issue 19) pp:6968
Publication Date(Web):September 8, 2016
DOI:10.1021/acs.chemmater.6b02653
The hybrid perovskites with special optoelectronic properties have attracted more attention to the scientific and industrial applications. However, because of the toxicity and instability of lead complexes, there is interest in finding a nontoxic substitute for the lead in the halides perovskites and solving the ambiguous crystal structures and phase transition of NH(CH3)3SnX3 (X = Cl, Br). Here, we report the bulk crystal growths and different crystal morphologies of orthorhombic hybrid perovskites NH(CH3)3SnX3 (X = Cl, Br) in an ambient atmosphere by bottom-seeded solution growth (BSSG) method. More importantly, detailed structural determination and refinements, phase transition, band gap, band structure calculations, nonlinear optical (NLO) properties, XPS, thermal properties, and stability of NH(CH3)3SnX3 (X = Cl, Br) single crystals are demonstrated. NH(CH3)3SnCl3 single crystal undergoes reversible structural transformation from orthorhombic space group Cmc21 (no. 36) to monoclinic space group Cc (no. 9) and NH(CH3)3SnBr3 belongs to the orthorhombic space group Pna21 (no. 33) by DSC, single-crystal X-ray diffraction and temperature-dependent SHG measurements, which clarify the former results. These results should pave the way for further studies of these materials in optoelectronics.
Co-reporter:Xiaolong Liu, Guangqiang Wang, Yangyang Dang, Shaojun Zhang, Hanlin Tian, Yan Ren and Xutang Tao
CrystEngComm 2016 vol. 18(Issue 10) pp:1818-1824
Publication Date(Web):27 Jan 2016
DOI:10.1039/C5CE02002F
This paper describes the crystal growth, structure and properties of a new semi-organic hybrid crystal with an accurate molecular formula of ZnMnCl4(TPPO)4 by a guest–host combination of ZnCl2(TPPO)2 and MnCl2(TPPO)2 for the first time and its formation is bidirectional. It crystallizes in the acentric space group Fdd2. The 3D framework of the crystal structure is formed by triphenylphosphine oxide (TPPO), linked with a mixture of zinc(II) chloride and manganese(II) chloride. A mixed occupancy of zinc and manganese atoms was designed to form a noncentrosymmetric coordination compound, which exhibits relatively strong second-order nonlinear properties. The powder of this crystal shows a phase-matchable SHG effect that is twice that of KH2PO4 (KDP). The crystal has a broad optical transmission range, relatively good stability and a wide band gap. It is also magnetic and luminescent. The properties of this new crystal make it a potential candidate for improved or even novel devices.
Co-reporter:Dehong Yu, Gordon J. Kearley, Guangfeng Liu, Richard A. Mole, Garry J. McIntyre and Xutang Tao
CrystEngComm 2016 vol. 18(Issue 27) pp:5070-5073
Publication Date(Web):23 May 2016
DOI:10.1039/C6CE00754F
The driving forces for the phase transition and relative stability of the two forms of CuQ2-TCNQ molecular crystals have been studied using inelastic neutron scattering (INS), density functional theory (DFT), and Hirshfeld surface analysis. DFT molecular dynamics (MD) simulations show that form-II has a lower enthalpy, but with increasing temperature form-I becomes thermodynamically stable due to the greater entropy. INS and MD simulations both show that the entropy of the hydrogen-bond network that holds molecules together within layers is higher in form-I. The interlayer π–π interactions are also weaker in form-I, leading to an overall “loosening” of the structure. The phase transition is kinetically hindered by the requirement to re-optimize the orientation of the layers. The strong H-bond interactions keep the in-plane atomic arrangement stable, while the weak interlayer π–π interactions provide the coupling between layers during the phase-transition. This subtle interplay of the two interactions maintains the integrity of the crystal upon phase transition even with dramatic physical dimension changes.
Co-reporter:Yanru Yin, Zhitai Jia, Wenxiang Mu, Zeliang Gao, Jian Zhang, and Xutang Tao
Crystal Growth & Design 2016 Volume 16(Issue 4) pp:1903-1906
Publication Date(Web):March 8, 2016
DOI:10.1021/acs.cgd.5b01414
Bulk Ca12Al14O33 (C12A7) crystals were successfully grown by the Czochralski (Cz) method. However, the surface exhibited severe cracking to a depth of about 1 mm during cooling of the as-grown crystals to room temperature. To determine the mechanism of the surface cracking we measured powder crystal X-ray diffraction, Raman spectroscopy, thermal gravimetry, and infrared spectroscopy of the OH-stretching band. It was found that the lattice parameters of the cracked crystal surface and the core were different. A weight increase in the TGA curve was observed during the cooling process. Furthermore, the OH– ion content of the crystal increased after annealing experiments. It can be concluded that incorporation of hydroxide ions caused the surface cracking of the as-grown C12A7 crystals.
Co-reporter:Yangyang Dang, Dianxing Ju, Lei Wang and Xutang Tao
CrystEngComm 2016 vol. 18(Issue 24) pp:4476-4484
Publication Date(Web):25 Apr 2016
DOI:10.1039/C6CE00655H
Hybrid halide perovskite based solar cells have demonstrated unprecedented progress in their efficiency, leading to efficiencies of up to 22.1%, in the past six years. Moreover, their intriguing properties of high dielectric constant, wide optical absorption range, low trap density, low non-radiative recombination and photoluminescence have attracted great research interest in the fields of optoelectronic applications and photovoltaics. This review briefly outlines the frontier of the research fields of perovskite materials, and summarizes the structure and growth of hybrid perovskite single crystals. Finally, the enormous challenges and the promising outlook of these active topics are highlighted.
Co-reporter:Xiangxin Tian, Qian Wu, Peng Zhao, Youxuan Sun, Zeliang Gao and Xutang Tao
CrystEngComm 2016 vol. 18(Issue 28) pp:5313-5319
Publication Date(Web):27 May 2016
DOI:10.1039/C6CE01101B
Large sized crystals of Na2TeW2O9 with dimensions up to 75 × 35 × 25 mm3 were successfully grown using an optimized top-seeded solution growth method. The as-grown Na2TeW2O9 single crystal exhibits well-developed faces with the major forms {200}, {002}, {202}, and {220}, which are in superior accordance with the ideal morphology predicted by the Bravais–Friedel and Donnay–Harker methods. A complete set of room temperature elastic, dielectric, and piezoelectric constants of Na2TeW2O9 single crystals was determined using resonance techniques and impedance analysis. Our results show that Na2TeW2O9 exhibits excellent piezoelectric properties (d15 = −23.93 pC N−1, d24 = −20.34 pC N−1), making the crystal a promising candidate for piezoelectric applications. The relationship between the piezoelectric properties and the crystal structure is also discussed.
Co-reporter:Yuan Yuan Wang, Yan Ren, Jie Liu, Cheng Qian Zhang, Sheng Qing Xia, Xu Tang Tao
Dyes and Pigments 2016 Volume 133() pp:9-15
Publication Date(Web):October 2016
DOI:10.1016/j.dyepig.2016.05.018
•The growth of Alq3 in several organic solvents has been investigated.•Two new solvated single crystals of Alq3(HCON(CH3)2) and Alq3((CH2OH)2) have been grown and solved.•The two solvated Alq3 crystals possess strong photoluminescence properties.•One-dimensional Alq3(HCON(CH3)2) microstructures have excellent optical wave guide features.Tris(8-hydroxyquinoline)aluminum(III) (Alq3) is characterized by crystallization in polymorphism both under vapor deposition and solvent evaporation. In this article, crystal growth of Alq3 in several organic solvents is studied. High quality bulk single crystals or crystalline microstructures are obtained, which depends on the varied conditions of crystallization. Two new crystalline solvates of Alq3(HCON(CH3)2) and Alq3((CH2OH)2) growing in N,N-dimethylformamide (DMF) and ethylene glycol (EG) have been obtained. X-ray diffraction analysis shows that their structures belong to new polymorphism bearing identical crystal symmetry, which is different to any solvated crystal phases reported before. The photoluminescent (PL) properties of the crystalline Alq3(HCON(CH3)2) and Alq3((CH2OH)2) are measured. Both crystals exhibit high quantum yield and long PL lifetime. In addition, the optical waveguide properties of Alq3(HCON(CH3)2) microstructures are investigated. It shows that solvated single-crystals or microstructures can be used as excellent light-emitting and propagation materials in miniaturized optoelectronic devices.
Co-reporter:Jie Liu;Dr. Guangfeng Liu;Dr. Yang Liu;Xiaoxin Zheng;Quanxiang Han;Xin Ye ;Dr. Xutang Tao
Chemistry – An Asian Journal 2016 Volume 11( Issue 11) pp:1682-1687
Publication Date(Web):
DOI:10.1002/asia.201600425
Abstract
Mechano-induced single-crystal-to-single-crystal (SCSC) phase transitions in crystalline materials that change their properties have received more and more attention. However, there are still too few examples to study molecular-level mechanisms in the mechano-induced SCSC phase transitions, making the systematic and in-depth understanding very difficult. We report that bis-(8-hydroxyquinolinato) palladium(II)-tetracyanoquinodimethane (PdQ2-TCNQ) and bis-(8-hydroxyquinolinato) copper(II)-tetracyanoquinodimethane (CuQ2-TCNQ) show very different mechano-response behaviors during the SCSC phase transition. Phase transition in CuQ2-TCNQ can be triggered by pricking on the crystal surface, while in PdQ2-TCNQ it can only be induced by applying pressure uniformly over the whole crystal face. The crystallography data and Hirshfeld surface analysis indicate that the weak intra-layer C−H⋅⋅⋅O, C−H⋅⋅⋅N hydrogen bonds and inter-layer stacking interactions determine the feasibility of the SCSC phase transition by mechanical stimuli. Weaker intra-layer interactions and looser inter-layer stacking make the SCSC phase transition occur much more easily in the CuQ2-TCNQ.
Co-reporter:Yangyang Dang;Yian Zhou;Xiaolong Liu;Dianxing Ju;Dr. Shengqing Xia;Dr. Haibing Xia ;Dr. Xutang Tao
Angewandte Chemie 2016 Volume 128( Issue 10) pp:3508-3511
Publication Date(Web):
DOI:10.1002/ange.201511792
Abstract
Hybrid perovskites have generated a great deal of interest because of their potential in photovoltaic applications. However, the toxicity of lead means that there is interest in finding a nontoxic substitute. Bulk single crystals of both cubic CH3NH3SnI3 and CH(NH2)2SnI3 were obtained by using the top-seeded solution growth method under an ambient atmosphere. Structural refinement, band gap, thermal properties, and XPS measurements of CH3NH3SnI3 and CH(NH2)2SnI3 single crystals are also reported in detail. These results should pave the way for further applications of CH3NH3SnI3 and CH(NH2)2SnI3.
Co-reporter:Yangyang Dang;Yian Zhou;Xiaolong Liu;Dianxing Ju;Dr. Shengqing Xia;Dr. Haibing Xia ;Dr. Xutang Tao
Angewandte Chemie International Edition 2016 Volume 55( Issue 10) pp:3447-3450
Publication Date(Web):
DOI:10.1002/anie.201511792
Abstract
Hybrid perovskites have generated a great deal of interest because of their potential in photovoltaic applications. However, the toxicity of lead means that there is interest in finding a nontoxic substitute. Bulk single crystals of both cubic CH3NH3SnI3 and CH(NH2)2SnI3 were obtained by using the top-seeded solution growth method under an ambient atmosphere. Structural refinement, band gap, thermal properties, and XPS measurements of CH3NH3SnI3 and CH(NH2)2SnI3 single crystals are also reported in detail. These results should pave the way for further applications of CH3NH3SnI3 and CH(NH2)2SnI3.
Co-reporter:Guangfeng Liu; Jie Liu; Hao Sun; Xiaoxin Zheng; Yang Liu; Xiaomin Li; He Qi; Xuedong Bai; Kenneth A. Jackson;Xutang Tao
Journal of the American Chemical Society 2015 Volume 137(Issue 15) pp:4972-4975
Publication Date(Web):April 7, 2015
DOI:10.1021/jacs.5b02637
The formation of crystalline materials has been studied for more than a century. Recent discoveries about the self-assembly of many inorganic materials, involving aggregation of nanoparticle (NP) precursors or pre-nucleation clusters, challenge the simple assumptions of classical crystallization theory. The situation for organic materials is even more of a terra incognita due to their high complexity. Using in situ high-temperature atomic force microscopy during the solvent-free crystallization of an organic compound [Ni(quinolone-8-thiolate)2], we observe long-range migration of NPs on a silica substrate and their incorporation into larger crystals, suggesting a non-classical pathway in the growth of the molecular crystal.
Co-reporter:Peng Zhao, Hengjiang Cong, Xiangxin Tian, Youxuan Sun, Chengqian Zhang, Shengqing Xia, Zeliang Gao, and Xutang Tao
Crystal Growth & Design 2015 Volume 15(Issue 9) pp:4484-4489
Publication Date(Web):July 2, 2015
DOI:10.1021/acs.cgd.5b00753
Single crystals of the polar material Cs2TeW3O12 (CTW) with dimensions up to 26 × 18 × 4 mm3 were successfully grown using a top-seeded solution growth method. The morphologies of the as-grown crystals have been described and compared with that obtained from the Bravais–Friedel and Donnay–Harker (BFDH) method. The crystal structure of CTW has been solved for the first time using single-crystal X-ray diffraction: the compound crystallizes in polar hexagonal space group P63 (No. 173) with cell parameters a = b = 7.3279(3) Å, c = 12.4075(5) Å, Z = 2, and V = 577.00(4) Å3. Thermal analysis shows that CTW is thermally stable up to 820 °C, at which it melts incongruently. Further high-resolution X-ray diffraction experiments gave a full-width at half-maximum of the rocking curve of 33″, indicating a good crystalline quality for the as-grown crystals. Optical transmittance spectra of CTW show a broad transmission range from 410 to 5310 nm. Powder second-harmonic generation (SHG) measurements with a 1064 nm laser indicates that CTW exhibits a strong SHG efficiency of about 1.5 the one of KTiOPO4. Polarization measurements indicate that CTW is not ferroelectric; i.e., the polarization is not “switchable”. In addition, CTW is nonhygroscopic and resistant to diluted HNO3 aqua-solution.
Co-reporter:Guangfeng Liu, Jie Liu, Xiaoxin Zheng, Yang Liu, Dongsheng Yuan, Xixia Zhang, Zeliang Gao and Xutang Tao
CrystEngComm 2015 vol. 17(Issue 12) pp:2569-2574
Publication Date(Web):20 Feb 2015
DOI:10.1039/C4CE02182G
Bulk semi-organic nonlinear optical (NLO) single-crystals of tri-diethylammonium hexachlorobismuthate (TDCB) with sizes up to 22 × 21 × 15 mm3 have been grown from concentrated hydrochloric acid by the slow-cooling method. TDCB crystallizes in the trigonal system, the R3c space group, with a = 14.699(4) Å and c = 19.102(5) Å. Its morphology has been indexed to reveal the major facets of the crystal to be {110} and {012}. Transmittance spectra of TDCB show an optical transmission in the entire visible region with the cutoff wavelength at 365 nm. The powder second harmonic generation (SHG) measured by using the Kurtz and Perry technique indicates that TDCB is a phase-matchable NLO material with a SHG efficiency of 1.8 times that of KH2PO4 (KDP). Its specific heat and thermal expansion were investigated as a function of temperature, and the relationship between the structure and the thermal properties has been discussed. Furthermore, laser-induced damage threshold measurements show a threshold up to 2.32 GW cm−2. All the results demonstrate that the semi-organic crystal TDCB is promising in NLO applications.
Co-reporter:Zeliang Gao, Xiangxin Tian, Junjie Zhang, Qian Wu, Qingming Lu, and Xutang Tao
Crystal Growth & Design 2015 Volume 15(Issue 2) pp:759
Publication Date(Web):December 22, 2014
DOI:10.1021/cg501574e
Bulk crystal of α-BaTeMo2O9 with dimensions up to 90 × 38 × 27 mm3 was grown successfully by a top-seeded solution growth method. In the crystal growth process, a low cooling rate (0.1–0.5 °C/day) and dynamic adjustment of rotating speed were adopted in order to stabilize the metastable growth and improve the crystal quality. The crystal facets {002}, {010}, {201̅}, {111} are in good accordance with the predicted growth morphology based on the Bravais–Friedel and Donnay–Harker method. The complete sets of the dielectric, elastic, and piezoelectric constants of the α-BaTeMo2O9 crystals have been determined by means of the resonant technique and impedance analysis at room temperature. The results show that the α-BaTeMo2O9 crystal possesses much smaller piezoelectric constants (d31 = −1.8 pm/V, d15 = 4.9 pm/V, and d31 = 0.3 pm/V) than that of β-BaTeMo2O9. In addition, the structural distortions and dipole moments of α-BaTeMo2O9 and β-BaTeMo2O9 were analyzed and calculated to explain the obvious differences upon the properties between the two crystals.
Co-reporter:Dehong Yu, Dehui Sun, Maxim Avdeev, Qian Wu, Xiangxin Tian, Qinfen Gu, and Xutang Tao
Crystal Growth & Design 2015 Volume 15(Issue 7) pp:3110
Publication Date(Web):June 17, 2015
DOI:10.1021/acs.cgd.5b00421
High-pressure synchrotron X-ray diffraction on the nonlinear optical crystal α-BaTeMo2O9 (α -BTM) has revealed a new polymorph of γ-BTM having a monoclinic space group of P21. This first order phase transition from the orthorhombic Pca21 to the new monoclinic P21 structure occurs at 3.8 GPa pressure. The mechanism of the phase transition under high pressure is attributed to the anisotropic pressure response along different crystallographic directions.
Co-reporter:Yangyang Dang, Yang Liu, Youxuan Sun, Dongsheng Yuan, Xiaolong Liu, Weiqun Lu, Guangfeng Liu, Haibing Xia and Xutang Tao
CrystEngComm 2015 vol. 17(Issue 3) pp:665-670
Publication Date(Web):26 Nov 2014
DOI:10.1039/C4CE02106A
Organic–inorganic hybrid perovskite materials have been receiving considerable attention due to their promising applications in many optoelectronic fields. However, some of the fundamental properties of perovskite materials are still disputed, because most of them are derived from a thin-film state. To comprehend the intrinsic characteristics in a single crystal, herein we report, for the first time, the bulk crystal growth of CH3NH3PbI3. Single crystals of tetragonal CH3NH3PbI3 with dimensions of 10 mm × 10 mm × 8 mm were grown by a temperature-lowering method in HI solution. Studies in to the refinement and orientations of the CH3NH3PbI3 single crystal structure were conducted based on a high quality crystal. The absorption edge of a CH3NH3PbI3 single crystal was located at about 836 nm, indicating that the band gap of CH3NH3PbI3 is approximately 1.48 eV, which is close to the theoretical results and smaller than those derived from polycrystalline and thin-films. CH3NH3PbI3 crystal exhibits a relatively wide absorption (from 250 nm to 800 nm) and a relatively good thermal stability.
Co-reporter:Yun Lv, Yang Liu, Xin Ye, Guangfeng Liu and Xutang Tao
CrystEngComm 2015 vol. 17(Issue 3) pp:526-531
Publication Date(Web):09 Sep 2014
DOI:10.1039/C4CE01212G
Mechanochromic luminescence via grinding-induced crystalline-to-amorphous transition in some organic materials has been well illustrated in recent years. Here, we focus on the luminescence reversion process induced by thermal annealing crystallization of a series of tetraphenylethene analogues. Through paired comparisons, we disclosed that the mechano-stimuli can not only destroy the crystallinity of crystalline materials but can also bring a significant effect on the amorphous-to-crystalline transition of amorphous materials. That is, only when an amorphous material underwent mechano-stimuli can it crystallize by thermal annealing to recover its emission. This grinding-facilitated annealing crystallization is rationalized to originate from the twisted and rotatable intramolecular conformation that can be altered by mechano-stimuli. Besides some special usage of the material as security paper or latent memory medium, the study presents new strategies to control the crystallization of organic semiconductors.
Co-reporter:Xiangxin Tian, Qian Wu, Peng Zhao, Zheng Wang, Xiaoxiao Feng, Conggang Li, Youxuan Sun, Shanpeng Wang, Zeliang Gao and Xutang Tao
CrystEngComm 2015 vol. 17(Issue 24) pp:4525-4532
Publication Date(Web):07 May 2015
DOI:10.1039/C5CE00639B
Single crystals of Bi2Mo2.66W0.34O12 with dimensions up to 70 mm × 55 mm × 45 mm were successfully grown using a top-seeded solution growth (TSSG) method with a MoO3–WO3 mixture as a flux. The material crystallizes in centrosymmetric space group P21/c (no. 14), with unit cell parameters of a = 7.7212(8) Å, b = 11.4938(12) Å, c = 11.9970(12) Å, and β = 115.5070(10)°. The as-grown crystals exhibit {100}, {010}, {011}, {110}, {021}, {012}, {120}, {−111}, {−102}, and {1−1−2} facets, which are in good agreement with the predicted growth morphology based on the Bravais–Friedel and Donnay–Harker (BFDH) method. High-resolution X-ray diffraction (HRXRD) measurement on the (040)-faced plate shows that the full-width at half-maximum (FWHM) of the rocking curve is 54′′, which indicates high crystal quality. Our measurements show that it melts congruently and exhibits a wide transmission range from 475 nm to 5200 nm. It is worth noting that Bi2Mo2.66W0.34O12 has a large birefringence (Δn = 0.24 at 480 nm), indicating that the crystal can be a promising polarizing optical material.
Co-reporter:Xixia Zhang, Fei Lou, Chunlong Li, Xiang Zhang, Ning Jia, Tongtong Yu, Jingliang He, Baitao Zhang, Haibing Xia, Shanpeng Wang and Xutang Tao
CrystEngComm 2015 vol. 17(Issue 21) pp:4026-4032
Publication Date(Web):23 Apr 2015
DOI:10.1039/C5CE00484E
Molybdenum disulfide (MoS2) has attracted a great deal of attention because of its outstanding physical, chemical and optoelectronic properties. The method used to prepare large sized MoS2 crystals of very high quality is still an important issue for determining the feasibility of its application. Herein, we propose a novel Sn flux method to grow single crystal MoS2, and bulk MoS2 single crystals with a size of 3 mm × 5 mm were successfully obtained by using a cooling rate of 2–4 °C h−1. The growth mechanism of the MoS2 crystal in Sn flux was investigated in detail using optical microscopy and atomic force microscopy (AFM). The obvious screw dislocation steps that are revealed suggest that the growth of MoS2 is controlled by a screw-dislocation-driven (SDD) spiral growth mechanism. The flux-grown MoS2 crystals were exfoliated to produce high-quality large-scale films using the liquid-phase exfoliation method. Using ultrathin MoS2 films as a saturable absorber, a passively Q-switched laser at a wavelength of 1.06 μm was constructed and operated, with a narrow pulse width of 326 ns.
Co-reporter:Yanbin Li, Zhitai Jia, Fei Lou, Baitao Zhang, Jingliang He, Xutang Tao
Optical Materials 2015 Volume 45() pp:235-238
Publication Date(Web):July 2015
DOI:10.1016/j.optmat.2015.03.045
•A novel disordered Yb:GAGG laser crystal.•Passive mode-locking performances of Yb:GAGG crystal was investigated by using a SESAM for the first time.•High-efficiency Watt-level picosecond pulse generation was obtained.A diode-pumped passively mode-locked Yb3+:Gd3Al0.5Ga4.5O12 (Yb:GAGG) laser has been investigated by using a semiconductor saturable absorber mirror (SESAM) for the first time. Pulses with duration of 1.6 ps were produced at the central wavelength of 1027.8 nm. At the absorbed pump power of 8.4 W, the maximum average output power of 1.02 W was obtained with the repetition rate of 45 MHz. The corresponding single pulse energy and the peak power were calculated to be 22.7 nJ and 14.2 kW, respectively.
Co-reporter:Dongsheng Yuan, Zeliang Gao, Zhitai Jia, Jun Shu, Yang Li, Xutang Tao
Optical Materials 2015 Volume 42() pp:435-440
Publication Date(Web):April 2015
DOI:10.1016/j.optmat.2015.02.001
•TbCOB crystal with a diameter of 35 mm has been successfully grown by Cz method.•The polarized Raman spectra were studied to analyze the vibrational structure.•The fluorescence properties of the X-cut, Y-cut, and Z-cut samples were measured.•The energy level diagram of Tb3+ in TbCOB crystal was discussed.•The lifetime decay indicates single exponential character with τ = 2.07 ms at RT.A single crystal of TbCa4O(BO3)3 (TbCOB) with diameter of 35 mm and length of 80 mm has been successfully grown using the Czochralski (Cz) method. The polarized Raman spectra were studied to analyze the vibrational structure of TbCOB, especially the modes from [BO3]3− triangles that are responsible for the nonlinear optical generation. The fluorescence properties of the X-cut, Y-cut, and Z-cut non-centrosymmetric TbCOB crystals were measured for the first time, and both f–d and f–f transitions were identified according to the energy level diagram. Based on the non-radiative energy transfer process, TbCOB crystal shows the characteristic emission of Tb3+ corresponding to 5D4 → 7F6,5,4,3 transitions with the green light of 542 nm (5D4 → 7F5) being the most prominent group. Additionally, the lifetime decay indicates single exponential character for the excited wavelength at 378 nm, following the result of τ = 2.07 ms at room temperature. The long fluorescence lifetime and good spectra properties of TbCOB single crystal indicate its potential optical prospects.
Co-reporter:Shanpeng Wang, Zeliang Gao, Xiang Zhang, Xixia Zhang, Chunlong Li, Chunming Dong, Qingming Lu, Minglei Zhao, and Xutang Tao
Crystal Growth & Design 2014 Volume 14(Issue 11) pp:5957-5961
Publication Date(Web):September 25, 2014
DOI:10.1021/cg501152j
Single crystal LiInS2 (LIS) is a promising candidate for mid-infrared (MIR) frequency conversion to obtain MIR laser output. Large-sized LIS crystals with a diameter of 16 mm and a length of 50 mm were grown by the modified Bridgman method. The as-grown LIS crystals were annealed in different atmospheres, and the effects of annealing on the electrical and optical properties were studied in detail. The visible-near-infrared and MIR transmission spectra of the crystals were studied before and after annealing in different atmospheres. The experimental results indicate that the optimal annealing conditions for a grown crystal are to use an atmosphere of LIS vapor at 700 °C for 160 h. The electrical properties were investigated before and after annealing in the LIS vapor atmosphere. After proper postgrowth annealing, the quality of the crystal was significantly improved, which resulted in an increase in the damage threshold from 0.9 to 1.2 J/cm2.
Co-reporter:Dongsheng Yuan, Zhitai Jia, Jian Wang, Zeliang Gao, Junjie Zhang, Xiuwei Fu, Jun Shu, Yanru Yin, Qiangqiang Hu and Xutang Tao
CrystEngComm 2014 vol. 16(Issue 19) pp:4008-4015
Publication Date(Web):12 Feb 2014
DOI:10.1039/C4CE00051J
Bulk TbCa4O(BO3)3 single crystals with diameter of 25 mm and length of 70 mm were successfully grown by the Czochralski (Cz) method for the first time to the best of our knowledge. The main problems of crystal growth were discussed and solved resulting in a high quality crystal. The crystalline perfection of the as-grown crystal was evaluated with full-width at half-maximum (FWHM) of the rocking curve being 35.05′′, and the optical homogeneity being 7.76 × 10−5. TbCa4O(BO3)3 crystallizes in the monoclinic space group Cm with unit cell parameters of a = 8.0715(7) Å, b = 16.0000(15) Å, c = 3.5454(3) Å, and β = 101.2550(10)°. Several interesting phenomena of atom occupancy and structure distortion were observed and analysed. Furthermore, the hardness, density, absorption and transmission spectra were measured. The TbCOB crystal has a Mohs hardness value of 5.58, and it exhibits a high transparency ranging from 490 nm to 1500 nm.
Co-reporter:Shanpeng Wang, Guandong Liu, Qiong Shi, Xiang Zhang, Xixia Zhang, Chunlong Li, Zeliang Gao, Chunming Dong, Qingming Lu and Xutang Tao
RSC Advances 2014 vol. 4(Issue 53) pp:27830-27836
Publication Date(Web):16 Jun 2014
DOI:10.1039/C4RA02740J
A large single LiGa3Te5 (LGT) crystal was grown with size up to Ø16 mm × 50 mm for the first time using a modified vertical Bridgman–Stockbarger method. LGT crystallizes in the non-centrosymmetric system, space group R32, with a = b = 14.343(7) Å, c = 17.617 Å, Z = 12, and V = 3139 Å3. A detailed description of the polyhedral connections in the LGT structure is presented. The X-ray rocking curve, specific heat and thermal conductivity are also investigated. The room-temperature transmission of the as-grown LGT without any coating is above the 40% level from 3.5 to 18 μm. The cut-off edges at short and long wavelength are 0.9 and 25 μm, respectively. Owing to its wide transparency range, LGT is a promising candidate for MIR and far-infrared NLO applications, and even for THz transmission and generation.
Co-reporter:Xiang Zhang, Shanpeng Wang, Huapeng Ruan, Guodong Zhang, Xutang Tao
Solid State Sciences 2014 Volume 37() pp:1-5
Publication Date(Web):November 2014
DOI:10.1016/j.solidstatesciences.2014.08.009
•A new phase of SiP2 has been grown in Sn flux.•A mineralizer was used for crystal growth.•It is a layered structure semiconductor and its structure is closely related to the known phase.A new orthorhombic phase of silicon diphosphide has been grown in Sn flux by using Gd as a mineralizer. It is a needle-like crystal and its structure has been determined through single crystal X-ray diffraction and elemental analysis. It crystallizes in the orthorhombic space group Pnma (No. 62, Z = 8) with cell parameters: a = 10.0908(19) Å, b = 3.4388(6) Å and c = 13.998(3) Å and the final R value is 0.0294. It has a layered structure that is closely related to the Pbam phase of SiP2. Its optical band gap is 1.45 eV and it decomposes at 1002 K.
Co-reporter:Shande Liu, Junjie Zhang, Zeliang Gao, Lei Wei, Shaojun Zhang, Jingliang He, Xutang Tao
Optical Materials 2014 Volume 36(Issue 4) pp:760-763
Publication Date(Web):February 2014
DOI:10.1016/j.optmat.2013.11.021
•The ratio of the Raman gain coefficient between YVO4 and α-BaTeMo2O9 was 0.53.•20.1 mJ 2nd-order Stokes, together with 7.2 mJ 3rd-order Stokes were obtained.•The conversion efficiency of the 2nd- and 3rd-order Stokes radiation was 35.9%.•A maximum 1497 nm pulse energy was 14.5 mJ, together with 2 mJ pulse energy at 1731 nm.The generations of high energy 2nd- and 3rd-order stimulated Raman scattering lasers based on the α-BaTeMo2O9 crystal were demonstrated for the first time. The Raman gain coefficient has been compared with that of the YVO4 crystal. A maximum total Stokes radiation energy of 27.3 mJ was obtained, containing 20.1 mJ 2nd-order Stokes energy at 1318 nm, together with 7.2 mJ 3rd-order Stokes energy at 1497 nm, giving an overall conversion efficiency of 35.9% and a slope efficiency of 54.5%. With an optical coating design, a total 3rd- and 4th-order Stokes energy of 16.5 mJ was generated. The maximum energy for 4th-order Stokes radiation at 1731 nm was 2 mJ. The pulse durations for the 2nd-, 3rd-, and 4th-order Stokes shift were 10 ns, 8.6 ns, and 5.2 ns, respectively. Our experimental results show that the α-BTM crystal is a promising Raman crystal for the generations of eye-safe radiations.
Co-reporter:Jian Wang ; Xiao-Cun Liu ; Sheng-Qing Xia
Journal of the American Chemical Society 2013 Volume 135(Issue 32) pp:11840-11848
Publication Date(Web):July 19, 2013
DOI:10.1021/ja403653m
For materials used in high-temperature thermoelectric power generation, the choices are still quite limited. Here we demonstrate the design and synthesis of a new class of complex Zintl compounds, Ca1–xRExAg1–ySb (RE = La, Ce, Pr, Nd, Sm) (P63mc, No. 186, LiGaGe-type), which exhibit a high figure of merit in the high-temperature region. Compared with the parent structure that is based on CaAgSb (Pnma, No. 62, TiNiSi-type), an interesting structural relationship is established which suggests that important size and electronic effects govern the formation of these multinary phases. According to theoretical calculations, such a structural transformation from the orthorhombic TiNiSi-type to the hexagonal LiGaGe-type also corresponds to an obvious modification in the electronic band structure, which explains the observed significant enhancement of the related thermoelectric properties. For an optimized p-type material, Ca0.84Ce0.16Ag0.87Sb, a figure of merit of ∼0.7 can be achieved at 1079 K, which is comparable to that of Yb14MnSb11 at the same temperature. In addition, due to the excellent thermal stability and high electrical conductivity, these materials are very promising candidates for high-temperature thermoelectric power generation.
Co-reporter:Guangfeng Liu ; Jie Liu ; Yang Liu ;Xutang Tao
Journal of the American Chemical Society 2013 Volume 136(Issue 2) pp:590-593
Publication Date(Web):December 27, 2013
DOI:10.1021/ja4102634
We report here a new polymorph of cocrystal CuQ2-TCNQ that shows an oriented single-crystal-to-single-crystal phase transition along its a-axis at ambient conditions. Upon mechanical stimulation, it converts into another polymorph accompanied by almost doubling its length and halving its thickness. Our crystallographic studies indicate the dramatic changes in crystal dimensions resulted from the prominent changes of molecular stacking patterns. A reasonable mechanism for the phenomenon was proposed on the basis of the structural, microscopic, and thermal analysis.
Co-reporter:Haibing Xia, Yan Ran, Houshen Li, Xutang Tao and Dayang Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 15) pp:4678-4684
Publication Date(Web):07 Feb 2013
DOI:10.1039/C3TA01540H
Nanoporous gold freestanding films (NPG FSFs) have been fabricated via overgrowth of gold onto self-assembled monolayers of gold nanocrystals at planar fluid–fluid interfaces. The resulting NPG FSFs are ligand-free on their surfaces and their sizes can be as large as several cm2. The NPG FSFs are fairly mechanically robust; their effective Young's moduli are of the order of about 10 GPa. The NPG FSFs exhibit efficient electrocatalytic activity for methanol oxidation with an excellent electrochemical endurance, which is attributed to the presence of high-index facets on the curved surfaces of gold ligaments in the NPG FSFs. It is found that the catalytic performance of as-prepared NPG FSFs is related to the curved-to-flat surface area ratios of gold ligaments in NPG FSFs. The highly curved surface areas in the NPG FSFs can be increased via optimizing the concentration of HAuCl4 and the citrate to HAuCl4 molar ratio in the electroless plating solution.
Co-reporter:Guodong Zhang, Huapeng Ruan, Xiang Zhang, Shanpeng Wang and Xutang Tao
CrystEngComm 2013 vol. 15(Issue 21) pp:4255-4260
Publication Date(Web):18 Mar 2013
DOI:10.1039/C3CE27003C
Single crystals of CdSiP2 (CSP) with the dimension of 8 mm in diameter and 40 mm in length were successfully grown using vertical Bridgman method. Optical observations showed the presence of macro-defects including flaws and inclusions in the as-grown crystals. The macro-defects can be restrained through controlling the process of polycrystalline synthesis and growth parameters. For the crystals with improved qualities, the high-resolution X-ray diffraction measurement on the (004)-faced plate indicates that the full-width at half-maximum (FWHM) of the rocking curve is 34′′. The phase-matching curves calculated from refractive indices indicate that, for 1.064 μm pumping, the CSP crystal will produce a noncritically phase-matched output at 6.2 μm through a type-I parametric process, and a noncritically phase-matched output at 5.0 μm through a type-II parametric process. For 1.55 μm and 2.00 μm pumping, the crystal yields continuous tunability from 2 to 6.5 μm through a type-I parametric process. The absorption coefficients for e-polarized light at 1.064 μm, 1.55 μm and 2.0 μm of the as-grown CSP crystal are 0.53 cm−1, 0.39 cm−1, and 0.25 cm−1, respectively.
Co-reporter:Qingfen Niu, Yunqiang Lu, Hongjian Sun, Xiaoyan Li, Xutang Tao
Dyes and Pigments 2013 Volume 97(Issue 1) pp:184-197
Publication Date(Web):April 2013
DOI:10.1016/j.dyepig.2012.12.012
Four novel organic semiconductor phenyl-oligothiophene derivatives containing acetylenic spacers, 5-(phenylethynyl)-2,2′:5′,2″-terthiophene, 5-(phenylethynyl)-2,2′:5′,2″:5″,2‴-quaterthiophene, 4-([2,2′:5′,2″-terthiophen]-5-ylethynyl)aniline, 4-((5′-iodo-[2,2′-bithiophen]-5-yl)ethynyl)aniline were synthesized and studied with respect to their thermal, photophysical, electrochemical and morphological properties. TGA and DSC results show all the oligomers have good thermal stability. Electrochemical measurements suggest the compounds can be used as photovoltaic materials. UV–vis spectra confirm all the molecules adopt close side-to-side packing, indicating H-aggregation. 4-([2,2′:5′,2″-Terthiophen]-5-ylethynyl)aniline exhibits excellent fluorescence properties when applied in an optoelectric field. XRD analysis indicates that the four compounds have a high degree of lamellar ordering and crystallinity. Film morphology properties reveal a clearly single-crystalline monoclinic morphology with lamellae parallel to the substrate, exhibiting that adjacent molecules have a strong intermolecular interaction. The potential liquid crystalline property is illustrated by DSC, XRD and polarization optical microscopy. These properties demonstrate that these oligomers could be promising candidates for the organic thin film materials and photovoltaic devices.Highlights► Four novel materials PE3T, PE4T, 3TEA, I2TEA were successfully synthesized. ► The thermal, optical, electrochemical and morphological properties were studied. ► Four molecules adopted H aggregation and exhibited high film performance. ► All the oligomers were promising candidates for the organic thin film materials.
Co-reporter:Dan Guo, Yan Ren, Jie Liu, Xutang Tao
Dyes and Pigments 2013 Volume 98(Issue 3) pp:384-392
Publication Date(Web):September 2013
DOI:10.1016/j.dyepig.2013.03.026
•A series of new organic salts based on imidazolium are developed for second-order nonlinear applications.•Nine single crystals have been obtained, among which two crystals show acentric crystal structure.•DITMS crystal exhibits a large macroscopic optical nonlinearity and excellent crystal growth characteristic.•The growth of the bulk DITMS crystal has been investigated.We have developed a new organic cation core structure, trans-1-[p-(N, N-dimethylamino) styryl]-3-methylimidozalium for second order nonlinear optical (NLO) applications. Among the eight crystals of imidozalium salts with various counter anions, trans-1-[p-[(N, N-dimethylamino) styryl]-3-methylimidozalium 1-naphthalenesulfonate (II) (DINS-1(II)) and trans-1-[p-(N, N-dimethylamino) styryl]-3-methylimidozalium mesitylenesulfonate (DITMS) exhibit acentric crystal structures. The former belongs to Pna21 space group, while the latter crystallizes in Pn phase. The macroscopic optical nonlinearity of the acentric crystals have been estimated by Kurtz and Perry powder test at various grain sizes. Compared to DINS-1(II), DITMS exhibits a relatively large second order nonlinearity benefiting from the almost parallel arrangement of the main molecular charge–transfer axis in lattice. The growth of the bulk DITMS crystal has been investigated.
Co-reporter:Jian Wang, Sheng-Qing Xia, Xu-Tang Tao
Journal of Solid State Chemistry 2013 Volume 198() pp:6-9
Publication Date(Web):February 2013
DOI:10.1016/j.jssc.2012.09.029
Through high temperature Pb-flux reactions, two new arsenide Zintl compounds, Ba3Zn2As4 and Ba3Cd2As4, were successfully obtained and their structures were accurately determined with Single-Crystal X-ray Diffraction. Both compounds are isotypic to Ba3Cd2Sb4 and crystallize in the monoclinic space group C2/m (No=12) with cell parameters of a=16.916(4)/17.089(3) Å, b=4.497(1)/4.6076(7) Å, c=7.225(2)/7.304(1) Å and β=113.147(2)/112.312(1) ° for Ba3Zn2As4 and Ba3Cd2As4, respectively. Electrical resistivity measurement on Ba3Cd2As4 reveals semiconducting behavior between 10 and 100 K, which results in a very small band gap of 0.01 eV. According to TG/DSC analyses, Ba3Cd2As4 exhibits good thermal stability and does not decompose below 950 K.Graphic abstractA polyhedral view of the crystal structure for Ba3T2As4 (T=Zn or Cd) in which Ba and As atoms are plotted as purple and red spheres, respectively.Highlights► Two new ternary Zintl compounds, Ba3Zn2As4 and Ba3Cd2As4, have been synthesized. ► Their structure features polyanionic layers constructed through [MAs4] tetrahedra. ► Ba3Cd2As4 has a very narrow band gap of 0.01 eV and are thermally stable up to 950 K.
Co-reporter:Houshen Li, Haibing Xia, Dayang Wang, and Xutang Tao
Langmuir 2013 Volume 29(Issue 16) pp:5074-5079
Publication Date(Web):April 4, 2013
DOI:10.1021/la400214x
Monodisperse, quasi-spherical silver nanocrystals (Ag NCs) have been produced directly in water via adding the aqueous solution of a mixture of AgNO3, sodium citrate, and KI into the boiling aqueous solutions of ascorbic acid (AA). The AA is used to significantly accelerate reduction of AgNO3 in order to promote a very fast nucleation, and the KI is used to tailor the growth of the Ag NCs into a quasi-spherical shape via its preferential adsorption on the NC {111} facets. The major role of citrate is to stabilize the newly formed NCs, whereas it has a minor contribution to reduction of AgNO3. The synergy of the effects of AA, citrate, and KI can significantly narrow the size distributions of the Ag NCs obtained so and transform the NC shapes to be truly quasi-spherical.
Co-reporter:Lei Wang, Yang Liu, Jia-xiang Yang, Xu-tang Tao and Zhi Liu
Chemical Communications 2012 vol. 48(Issue 46) pp:5742-5744
Publication Date(Web):20 Apr 2012
DOI:10.1039/C2CC31021J
Fluorescent microspheres consisting of a conjugated phenylenevinylene 3B2B doped with a fluorenone derivative DSFO were prepared by a reprecipitation method. The DSFO-doped 3B2B microspheres (DMPs) exhibited significantly reduced fluorescence from 3B2B (donor) and strongly enhanced emission from DSFO (acceptor), which is highly sensitive to the concentration of metalloprotein.
Co-reporter:Jian Wang ; Sheng-Qing Xia
Inorganic Chemistry 2012 Volume 51(Issue 10) pp:5771-5778
Publication Date(Web):May 7, 2012
DOI:10.1021/ic300308w
Two new ternary Zintl phases, Sr5Sn2As6 and Eu5Sn2As6, have been synthesized, and their structures have been accurately determined through single-crystal X-ray diffraction. Both compounds crystallize in orthorhombic space group Pbam (No. 55, Z = 2) with cell parameters of a = 12.482(3)/12.281(5) Å, b = 14.137(3)/13.941(5) Å, and c = 4.2440(10)/4.2029(16) Å for Sr5Sn2As6 (R1 = 0.0341; wR2 = 0.0628) and Eu5Sn2As6 (R1 = 0.0324; wR2 = 0.0766), respectively. Their structure belongs to the Sr5Sn2P6 type, which can be closely related to the Ca5Ga2As6 type. Electronic band structure calculations based on the density functional theory reveal an interesting electronic effect in the structure formation of these two types of Zintl phases, which substantially affect their corresponding electronic band structure. Related studies on the thermal stability, magnetism, and thermoelectric properties of Eu5Sn2As6 are presented as well.
Co-reporter:Zuo-Qin Liang, Zeng-Ze Chu, De-Chun Zou, Xiao-Mei Wang, Xu-Tang Tao
Organic Electronics 2012 Volume 13(Issue 12) pp:2898-2904
Publication Date(Web):December 2012
DOI:10.1016/j.orgel.2012.08.041
Two pyrene derivatives (PVPP and TPVPP) bearing 4-(2,2-diphenyl-vinyl)-phenyl side unit were developed for organic light-emitting diodes. Their photophysical, thermal, electrochemical, and electroluminescent properties as well as the film morphologies have been investigated in detail. Both of them exhibit high solid-state quantum yields, good thermal stability, and high glass-transition temperatures in the range of 127–150 °C. In particular, it is found that multiple side units can significantly affect the electrochemical properties to improve the electron injection. The LUMO energy level of TPVPP is −2.76 eV, which is very close to that of commonly used electron transport materials. The maximum luminance of OLED devices using TPVPP as an emitter layer is 103835 cd/m2 with a maximum current efficiency of 5.19 cd/A and a maximum power efficiency of 3.38 lm/W.Graphical abstractHighlights► PVPP and TPVPP show high solid-state quantum yields. ► PVPP and TPVPP exhibit high glass-transition temperatures of 127–150 °C. ► The amorphous films of PVPP and TPVPP are morphological stability. ► Multiple substitutions are beneficial to decrease the LUMO energy level. ► PVPP and TPVPP are promising host-emitters with high efficiency and stability.
Co-reporter:Qingxin Zheng, Bo Li and Xutang Tao
CrystEngComm 2011 vol. 13(Issue 3) pp:750-752
Publication Date(Web):06 Dec 2010
DOI:10.1039/C0CE00778A
Pure-phase BaTeMo2O9 polycrystals with uniform particle shape and size have been successfully synthesized in a supercritical water system and the novel optical properties were reported.
Co-reporter:Zuo-Qin Liang, Zeng-Ze Chu, Jia-Xiang Yang, Chun-Xue Yuan, Xu-Tang Tao, De-Chun Zou
Synthetic Metals 2011 Volume 161(15–16) pp:1691-1698
Publication Date(Web):August 2011
DOI:10.1016/j.synthmet.2011.06.005
Two X-shaped compounds (7 and 9) based on pyrene have been synthesized and well characterized. These compounds exhibit good thermal stabilities and high fluorescence yields. In addition, an interesting phenomenon is discovered that the fluorescence of compound 9 can be reversibly converted from red to orange in the solid state. Organic light-emitting diodes have been fabricated using the X-shaped compounds as the host emitter with low turn-on voltage up to 2.35 V. The device based on compound 7 exhibits orange-red electroluminescence (CIE: 0.58, 0.42) with a maximum luminance of 4798.4 cd/m2, a maximum current efficiency 1.26 cd/A, and a power efficiency of 1.06 l m/W.Highlights► Two X-shaped compounds based on pyrene are designed, synthesized, and characterized. ► Balancing the relationship between fluorescent enhancement and charge carrier. ► The fluorescence of compound 9 can be reversibly converted from red to orange. ► The device based on compound 7 exhibits better EL performances.
Co-reporter:Zuo-Qin Liang, Ye-Xin Li, Jia-Xiang Yang, Yan Ren, Xu-Tang Tao
Tetrahedron Letters 2011 Volume 52(Issue 12) pp:1329-1333
Publication Date(Web):23 March 2011
DOI:10.1016/j.tetlet.2011.01.060
Two new pyrene-based fluorophores, namely 1-[4-(2,2-diphenylvinyl)phenyl]pyrene (PVPP) and 1,3,6,8-tetrakis[4-(2,2-diphenylvinyl)phenyl]pyrene (TPVPP), were synthesized through Suzuki coupling reaction and well characterized. PVPP successfully suppresses the fluorescence quenching of pyrene units in the solid state, displaying aggregation-induced enhanced emission. Despite the same substituent, TPVPP shows a different fluorescent behavior. On the basis of the crystal structures, the distinct optical behavior is discussed and clarified. The intermolecular C–H⋯π interaction has a dramatic effect on their photophysical properties in the solid state.
Co-reporter:Xiaomei Wang ; Feng Jin ; Zhigang Chen ; Shouqing Liu ; Xiaohong Wang ; Xuanming Duan ; Xutang Tao ;Minhua Jiang
The Journal of Physical Chemistry C 2011 Volume 115(Issue 3) pp:776-784
Publication Date(Web):December 29, 2010
DOI:10.1021/jp1081005
A new family of dendrimers with a naphthaline-core flanked on both sides by triphenylamine-branching was successfully synthesized and presented an increasing two-photon absorption (TPA) cross section from 959 to 9575 GM with the generation number from 1 to 3. These dendrimers can efficiently initiate the acrylate resins to polymerization to obtain very regular diamond structures and display higher two-photon polymerization (TPP) efficiency and sensitivity with the generation number. The overall TPP processes involved in two-photon excitation, intramolecular charge transfer, and intramolecular energy transfer as well as intermolecular electron transfer between initiator and monomer are described. Steady-state fluorescence and time-resolved decay dynamics revealed that the light energy was absorbed by peripheral triphenylamine unit and then transferred to generation 1, the energy funnel. Although strong interaction between dendritic initiator and monomer has been observed based on fluorescence quenching measurements, no intermolecular energy transfer but electron transfer is confirmed by the cyclic voltammograms and HOMO−LUMO measurements. That is, the dendritic initiator first produces the excited state via two-photon absorption, then transfers an electron to an acrylate monomer, and finally induces the later to polymerize.
Co-reporter:ChunXue Yuan;Qian Xin;HuiJun Liu;Lei Wang;MinHua Jiang
Science China Chemistry 2011 Volume 54( Issue 4) pp:587-595
Publication Date(Web):2011 April
DOI:10.1007/s11426-011-4224-z
Tröger’s base (TB) is a well-known chiral molecule with rigid concave shape that makes it applicable in different areas such as superamolecular chemistry, molecular recognition, biological labeling, and so on. In this article, we briefly summarize some recent research progress in the optoelectronic properties of novel TB analogues and their applications in optoelectronic field with emphasis on the developments achieved in our group.
Co-reporter:Zhengbo Jiao ; Haibing Xia ;Xutang Tao
The Journal of Physical Chemistry C 2011 Volume 115(Issue 16) pp:7887-7895
Publication Date(Web):March 31, 2011
DOI:10.1021/jp111605j
In this article, we describe a series of experiments that systematically addressed and clarified the effects of iodide, silver ions, and ascorbic acid (AA) concentration on the morphology of gold nanorods (Au NRs) during the overgrowth process. When iodide ions, silver ions, or both were present in the growth solution, a morphology of Au nanocrystals ranging from thick NRs, cuboidal shaped NRs, dogbone-like NRs, to dumbbell NRs, respectively, was obtained. The appearance of the third peak in the UV−vis spectra indicates the formation of lobes on the tips of Au NRs. In addition, when different seeds (such as Au NRs of short aspect ratio and spherical Au nanocrystals) whose {111} facets were covered by iodide ions were used, horns of different length on Au seeds were formed. Taken together, the results mentioned above and cross section change of the tips of Au NRs, two lobes instead of four formed on each tip of the Au NRs are explained for the first time, and their growth from {111} facets is assisted by the formation of AgI, which can catalytically reduce Au ions into atoms on those facets. The optical spectra of nanostructured Au crystals can be tuned from 520 to 955 nm by controlling their tip curvature or platinum coating. A wide color gamut can be readily obtained by using a random dispersion of nanostructured Au NR-based crystals.
Co-reporter:Q.X. Zheng, B. Li, H.D. Zhang, J.J. Zheng, M.H. Jiang, X.T. Tao
The Journal of Supercritical Fluids 2009 Volume 50(Issue 1) pp:77-81
Publication Date(Web):August 2009
DOI:10.1016/j.supflu.2009.04.002
Pure YAG and rare earth-doped YAG ultra-fine particles with suitable morphology were obtained from a novel synthesis process by employing supercritical water. The synthesis process includes two steps including precursor precipitation and hydrothermal treatment in supercritical water system. The precursor was prepared by using yttrium nitrate, aluminum nitrate, rare earth nitrate and ammonium hydrogen carbonate aqueous solution as the starting materials. The YAG particles synthesized were mono-dispersed, featuring spherical or polyhedron shape with the size ranging from 100 nm to 500 nm. Factors influencing the properties of the final products were investigated in details. Structure characterization, morphology observation of the products were analyzed through XRD, SEM (scanning electron microscope) and other characterization techniques, respectively.
Co-reporter:Q.X. Zheng, B. Li, M. Xue, H.D. Zhang, Y.J. Zhan, W.S. Pang, X.T. Tao, M.H. Jiang
The Journal of Supercritical Fluids 2008 Volume 46(Issue 2) pp:123-128
Publication Date(Web):September 2008
DOI:10.1016/j.supflu.2008.04.014
Supercritical water and subcritical water as new reaction medium was firstly used to synthesize YVO4 and rare earth-doped YVO4 ultra-fine particles. Such synthesis was a simple one-step process by using vanadium oxide, yttrium nitrate, rare earth nitrate and potassium hydroxide aqueous solution as the starting materials. It was found that the structure and morphology of the product were affected by various reaction conditions. The synthesized YVO4 particles were nearly cubic and cuboid shape with the average size ranging from 50 nm to 200 nm. The products were analyzed by structure characterization of XRD, morphology observation of SEM, TEM and other characterization techniques. The luminescent properties of rare earth-doped YVO4 powders excited by UV irradiation were reported.
Co-reporter:Shanpeng Wang, Xixia Zhang, Xiang Zhang, Chunlong Li, Zeliang Gao, Qingming Lu, Xutang Tao
Journal of Crystal Growth (1 September 2014) Volume 401() pp:150-155
Publication Date(Web):1 September 2014
DOI:10.1016/j.jcrysgro.2014.02.043
•60–100 g LISe polycrystals were obtained using a two-step synthesis method.•Large LiInSe2 single crystals were grown by the modified Bridgman technique.•The 50% transmittance level of LiInSe2 extends from 0.65 to 12.6 μm.A mid-infrared LiInSe2 (LISe) single crystal was successfully grown by the modified vertical Bridgman technique with dimensions of about ∅12 mm×30 mm. A large amount of high purity polycrystalline LISe used for crystal growth was synthesized in one run by a novel two-step synthesis method. The thermal properties of the crystal were carefully investigated by measuring the melting point, specific heat, and thermal diffusivity, and deriving the thermal conductivity. The transmission spectrum showed that the 50% transmittance level extends from 0.65 to 12.6 μm. The excellent thermal conductivity and optical properties indicate that LISe is one of only a few promising candidates for high average power nanosecond OPOs pumped by ~1 μm lasers.
Co-reporter:Dongsheng Yuan, Yang Li, Jun Shu, Zeliang Gao, Zhitai Jia, Zhengping Wang, Xutang Tao
Journal of Crystal Growth (1 January 2016) Volume 433() pp:59-62
Publication Date(Web):1 January 2016
DOI:10.1016/j.jcrysgro.2015.10.003
•The largest deff of TbCOB crystal was 1.39 pm/V.•TbCOB crystal was grown along the optimum SHG direction using the μ-PD method.•A high efficiency SHG can be realized through the μ-PD grown TbCOB crystal.•The directional growth for NLO crystal devices by using μ-PD was feasible.Towards the spatial optimum phase matching (PM) crystal device through a novel way, the micro-pulling-down (μ-PD) technique was used for crystal growth along second-order harmonic generation (SHG) direction for the first time to the best of our knowledge. In this paper, the spatial distribution of |deff| for a potential nonlinear optical (NLO) crystal TbCa4O(BO3)3 (TbCOB) at 1064 nm was calculated and analyzed firstly, and the PM angle (113°, 46°) was found to possess the largest deff value (type-I) being on the order of 1.39 pm/V. Along the optimum SHG direction, a rod-shape TbCOB crystal with 3 mm in diameter was successfully grown by using the μ-PD method. After simple cutting and polishing of the ends for μ-PD grown crystal, a high SHG efficiency (single-pass light reached up to 57%) was realized through a Nd:YAG pico-second laser at 1064 nm, which was comparable to that of crystal samples from Czochralski (Cz) growth. TbCOB crystals also exhibit a high laser damage threshold of >15 GW/cm2.
Co-reporter:Yanbin Li, Zhitai Jia, Baitao Zhang, Jingliang He, Xutang Tao
Journal of Crystal Growth (1 April 2015) Volume 415() pp:20-24
Publication Date(Web):1 April 2015
DOI:10.1016/j.jcrysgro.2014.12.026
•A bulk disordered Yb3+:Gd3(AlxGa1−x)5O12 (Yb:GAGG) laser crystal with dimensions of Φ26 mm×30 mm has been successfully grown by the Czochralski method.•The high quality of the as-grown crystal was confirmed by the XRC with a FWHM of 43.34׳׳.•The effective segregation coefficients of Yb3+ and Al3+ ions in the crystal were measured to be 1.25 and 1.20, respectively.•The thermal properties, including the thermal expansion, specific heat, thermal diffusion coefficient and thermal conductivity were measured for the grown crystal.Bulk single crystals of Yb3+:Gd3(AlxGa1−x)5O12 (Yb:GAGG) with dimensions of Φ26 mm×30 mm were successfully grown using the Czochralski method. The nominal Yb and Al contents in the raw materials were 5.0 and 10.0 at%, respectively. The effective segregation coefficients of Yb3+ and Al3+ ions were measured, and the doping concentrations of Yb3+ and Al3+ ions in the crystal were calculated to be 6.25–6.03 at% and 12.0–11.67 at% along the crystal growth direction, respectively. The crystalline perfection of the as-grown crystal was evaluated by high-resolution X-ray diffraction (HRXRD). The thermal properties, including thermal expansion, specific heat and thermal conductivity, have been studied in detail. In addition, the thermal-optical coefficient and the thermal shock resistance parameters were also calculated. Our results show that Yb:GAGG crystal has potential application in the field of high power solid state laser.
Co-reporter:Ci Wang, Jie Sun, Huiyang Gou, Shanpeng Wang, Jian Zhang and Xutang Tao
Physical Chemistry Chemical Physics 2017 - vol. 19(Issue 14) pp:NaN9565-9565
Publication Date(Web):2017/03/15
DOI:10.1039/C7CP01312D
In view of their high nonlinear optical coefficients and good phase-matching properties, CdSiP2 (CSP) crystals are considered as one of the most promising materials in the field of nonlinear optical applications. However, the slight absorption losses around 1.34 μm and 1.78 μm under e-polarized light have been affecting its performance. In this study, first-principles calculations were performed to identify the effects of various charge defects on the absorption properties. Different intrinsic defects in the CSP crystal were calculated using the HSE method and compared according to the specific chemical environments in the experiments. The results show that the point defects of V2−Cd, Si2+Cd, and V4−Si, which can be spontaneously formed, are dominant in the Cd-poor environment. The combination of Si2+Cd and V2−Cd defects is the most favorable cluster in the Cd-poor case because of its relatively low formation energy. Furthermore, the antisite defect SiCd was found to be responsible for the main absorption peaks at 1.34 and 1.78 μm in the experimental spectra, whereas other defects and clusters, such as the defects Si2+Cd and V0Si, also contribute to these red shifted absorptions. Our results intend to provide a guideline for adjusting the optical absorption in CSP by modifying its defects.
Co-reporter:Lei Wang, Yang Liu, Jia-xiang Yang, Xu-tang Tao and Zhi Liu
Chemical Communications 2012 - vol. 48(Issue 46) pp:NaN5744-5744
Publication Date(Web):2012/04/20
DOI:10.1039/C2CC31021J
Fluorescent microspheres consisting of a conjugated phenylenevinylene 3B2B doped with a fluorenone derivative DSFO were prepared by a reprecipitation method. The DSFO-doped 3B2B microspheres (DMPs) exhibited significantly reduced fluorescence from 3B2B (donor) and strongly enhanced emission from DSFO (acceptor), which is highly sensitive to the concentration of metalloprotein.
Co-reporter:Haibing Xia, Yan Ran, Houshen Li, Xutang Tao and Dayang Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 15) pp:NaN4684-4684
Publication Date(Web):2013/02/07
DOI:10.1039/C3TA01540H
Nanoporous gold freestanding films (NPG FSFs) have been fabricated via overgrowth of gold onto self-assembled monolayers of gold nanocrystals at planar fluid–fluid interfaces. The resulting NPG FSFs are ligand-free on their surfaces and their sizes can be as large as several cm2. The NPG FSFs are fairly mechanically robust; their effective Young's moduli are of the order of about 10 GPa. The NPG FSFs exhibit efficient electrocatalytic activity for methanol oxidation with an excellent electrochemical endurance, which is attributed to the presence of high-index facets on the curved surfaces of gold ligaments in the NPG FSFs. It is found that the catalytic performance of as-prepared NPG FSFs is related to the curved-to-flat surface area ratios of gold ligaments in NPG FSFs. The highly curved surface areas in the NPG FSFs can be increased via optimizing the concentration of HAuCl4 and the citrate to HAuCl4 molar ratio in the electroless plating solution.
