JOURNAL OF LUMINESCENCE
·
2018
·
IF 2.732
Qiang Shi,Qingru Wang,Dong Zhang,Qinglin Wang,Shuhong Li,Wenjun Wang,Quli Fan,Junying Zhang
In this study, Gallium oxide (Ga 2 O 3 ) thin films were deposited by vacuum thermal evaporation technique. The effects of annealing temperature on the structural, optical and photoluminescence (PL) properties of Ga 2 O 3 thin films were investigated in detail. The Ga 2 O 3 thin films annealed at lower temperatures were amorphous , while those annealed at above 800 °C were nanocrystalline . The annealing temperature increasing from 400 to 1100 °C results in the band-gap increase from 4.70 to 5.13 eV due to the reduction in density of defect states. Under the excitation at 250 nm, the PL spectra of thin films consisted of a UV emission (300 nm) and two blue emissions (400 nm and 438 nm). The UV and blue luminescence intensities increased as the annealing temperature was increased from 400 to 1100 °C. The blue luminescence is suggested to originate from the recombination of trapped electrons in the donor with trapped holes in the acceptor, where the origin of the donor should be an double ionized oxygen vacancy ( V O ++ ) and the acceptor should be a gallium vacancy ( V Ga ) or gallium-oxygen vacancy pair ( V Ga - V O ++ ).
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
POWDER DIFFRACTION
·
2018
·Vol. 33
·期 2
·115-120
·
IF 0.519
Jing Wu,Jikang Jian,Shufang Wang,Shuang Guo,Renbo Lei,Haitao Liu
The Bi4Te3 films with well-ordered orientation and microstructure were successfully prepared on SiO2 substrate by a vacuum thermal evaporation deposition technique for the first time. We discussed the effects of evaporation temperature and substrate temperature on the phase and its well-ordered growth of Bi4Te3 films. The formation of Bi4Te3 phase is owing to the differences of the saturated vapor pressure. The thermoelectric transport properties of the Bi4Te3 films were investigated and the (00l)-oriented nanopillars array film has a better electrical transport performance, whose value of PF is 0.032 mWm−1 K−2 at 339 K, approaching twice that of the non-oriented ordinary film. The enhanced electrical properties of Bi4Te3 films could be achieved via the high-crystallinity well-controlled (00l)-oriented nanopillars array.
研究领域:
材料科学
·
热电材料
·
薄膜制备技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 41
·14409-14422
·
IF 7.059
Xingyue Liu,Xianhua Tan,Zhiyong Liu,Xuning Zhang,Tielin Shi,Guanglan Liao
CsPbBr3 photodetectors (PDs) are attracting tremendous attention for their superior properties, such as ultrafast light response and high chemical stability. However, the widely-used spin-coating technique involved in the preparation process of CsPbBr3 PDs restricts the construction of large-scale PD arrays, making it challenging for their applications in high-resolution image sensing. Here, we demonstrate fully vapor-deposited CsPbBr3 PDs with all the functional layers deposited through an evaporation route. The employment of an inexpensive copper(II) phthalocyanine (CuPc) hole conductor and the abandonment of the electron conductor can significantly decrease the whole production costs. An ultrathin MoO3 buffer layer is further introduced to passivate the defect densities of the CsPbBr3 perovskite and tailor the band alignment of the whole device. The reduced interface energy barrier and non-radiative recombination loss of the MoO3-modified devices are revealed by both experimental characterization and theoretical density functional theory (DFT) analysis. The best-performing MoO3-modified CsPbBr3 PD achieves an ultrafast response time of 0.96 μs, an ultrahigh on/off ratio of 1.17 × 106 and a detectivity of 5.22 × 1012 Jones at 0 V bias voltage. This performance is one of the best among all the self-powered electron/hole-conductor-free perovskite PDs. A large-area (57.8 cm2) image sensor comprising 25 × 25 CsPbBr3 PD arrays is further fabricated. Owing to the intrinsic advantages of the evaporation technique in depositing large-area and uniform films, the as-designed 625-pixel sensor exhibits a salient imaging capability. Our work opens up new avenues for the mass production of cost-effective, large-area and high-performing CsPbBr3 PD arrays for applications in image sensing.
研究领域:
材料科学
·
电子工程
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Jingjing Liu,Mengsha Cao,Zhengdong Feng,Xiaomeng Ni,Jing Zhang,Jianhua Qiu,Shuai Zhang,Huafei Guo,Ningyi Yuan,Jianning Ding
Chemical bath–deposited cadmium sulfide (CBD-CdS) is the most widely used buffer layer material for antimony selenosulfide (Sb 2 (S,Se) 3 ) photovoltaic devices , but its medium band gap, large band gap offset with transparent conducting oxides , and surface defects must be addressed to improve its applicability. Hexagonal CdS films (60 nm thick) prepared using the thermal evaporation method were used as the buffer layers of Sb 2 (S,Se) 3 photovoltaic devices. Compared with CBD-CdS (60 nm thick), thermal evaporation–deposited CdS (TED-CdS) films have a larger band gap and fewer surface defects. The Sb 2 (S,Se) 3 film deposited on TED-CdS is more compact, and its 1D ribbons are stacked more vertically to the substrate. The band gap offset between CdS and fluorine-doped tin oxide glass decreases from 0.76 eV (CBD-CdS) to 0.60 eV (TED-CdS). Therefore, suppressed electron trap density and charge recombination, as well as improved light harvesting, are achieved. By replacing CBD-CdS with TED-CdS, the best device efficiency increases from 6.14 % to 7.16 %, with the open circuit voltage, short-circuit current density, and fill factor increasing from 0.660 V, 15.96 mA/cm 2 , and 58.37 % to 0.664 V, 17.39 mA/cm 2 , and 62.85 %, respectively. The device stability and reproducibility are also improved.
研究领域:
材料科学
·
光伏技术
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Yanyan Li,Wei Li,Yalun Xu,Ruiming Li,Tian Yu,Qianqian Lin
Perovskite solar cells are one of the most promising thin-film photovoltaic techniques, which have an unprecedented progress in the last decade. It is well-recognized in the perovskite community that nonradiative recombination losses and the open-circuit voltage deficit are the dominant limiting factors to further improve the device efficiency. Recently, multiple groups have reported that lead iodide can effectively passivate both perovskite grain boundaries and the interfaces between perovskite and charge transport layers. However, most of the excess PbI2 was processed with solution methods and formed PbI2 grains, which cannot cover perovskite layers completely. It is also very challenging to spin-coat PbI2 layers directly on perovskites, which requires orthogonal solvents. In this work, we deposit additional PbI2 thin layers directly on perovskite thin films via thermal evaporation. The impact of PbI2 layers on the perovskite thin films and devices is systematically investigated. It was found that the evaporated PbI2 thin films can effectively reduce the nonradiative recombination and enhance the device performance. The optimized thickness of the PbI2 layer was determined to be around 10 nm, which results in a relatively high Voc of 1.18 V and power conversion efficiency of 21.52%.
研究领域:
材料科学
·
光伏技术
·
界面工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2020
·Vol. 10
·期 15
·8905-8909
·
IF 3.119
Jingchen Hua,Xi Deng,Cheng Niu,Fuzhi Huang,Yong Peng,Wangnan Li,Zhiliang Ku,Yi-bing Cheng
All-inorganic CsPbBr3 perovskite solar cells have triggered incredible interest owing to their superior stability, especially under high temperature conditions. Different from the organic–inorganic hybrid perovskites, inorganic CsPbBr3 perovskite always need a high annealing temperature for the formation of a cubic phase. Generally, the higher temperature (over 300 °C) and longer annealing time will promote the growth of CsPbBr3, resulting in larger grain sizes and lower trap density in the crystals. However, CsPbBr3 perovskite can also be damaged by excessive annealing temperature (∼350 °C) and time, since PbBr2 only has a melting temperature close to 357 °C. To address this issue, herein, we developed a novel pressure-assisted annealing method to prevent the sublimation of PbBr2 at high temperature. The CsPbBr3 films were firstly deposited by sequential thermal evaporation, and then annealed at 335 °C in an alloy pressure vessel. By controlling the pressure of the vessel, we obtained CsPbBr3 films with various morphologies. At normal atmospheric pressure, the as-prepared CsPbBr3 film exhibited small grain sizes and was full of pinholes. With the increase of annealing pressure, the grain sizes of the film showed a significant increasing trend, and the pinholes gradually vanished. When the pressure value came to 10 MPa, compact and uniform CsPbBr3 films with large grain sizes were obtained. Based on these films, CsPbBr3 perovskite solar cells with FTO/compact-TiO2/CsPbBr3/carbon architecture achieved a champion power conversion efficiency of 7.22%.
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
PubMed
高影响因子
Nanomaterials
·
2019
·Vol. 9
·期 12
·1760
·
IF 4.034
Ping Fan,Huan-Xin Peng,Zhuang-Hao Zheng,Zi-Hang Chen,Shi-Jie Tan,Xing-Ye Chen,Yan-Di Luo,Zheng-Hua Su,Jing-Ting Luo,Guang-Xing Liang
Lead-free double perovskites have been considered as a potential environmentally friendly photovoltaic material for substituting the hybrid lead halide perovskites due to their high stability and nontoxicity. Here, lead-free double perovskite Cs2AgBiBr6films are initially fabricated by single-source evaporation deposition under high vacuum condition. X-ray diffraction and scanning electron microscopy characterization show that the high crystallinity, flat, and pinhole-free double perovskite Cs2AgBiBr6films were obtained after post-annealing at 300 °C for 15 min. By changing the annealing temperature, annealing time, and film thickness, perovskite Cs2AgBiBr6solar cells with planar heterojunction structure of FTO/TiO2/Cs2AgBiBr6/Spiro-OMeTAD/Ag achieve an encouraging power conversion efficiency of 0.70%. Our preliminary work opens a feasible approach for preparing high-quality double perovskite Cs2AgBiBr6films wielding considerable potential for photovoltaic application.Keywords:lead-free;perovskite solar cell;thin film;single-source vapor deposition
研究领域:
材料科学
·
可再生能源
·
太阳能电池技术
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）