Journal of Physical Chemistry C
·
2018
·
IF 4.484
Xiangqi Wang,Junbo Gong,Xueyan Shan,Min Zhang,Zilong Xu,Rucheng Dai,Zhongping Wang,Shimao Wang,Xiaodong Fang,Zengming Zhang
During the last few years, the organic–inorganic hybrid methylammonium lead halide perovskite, CH3NH3PbX3 (MAPbX3, X = I–, Cl–, Br–), has received great interest in the field of photovoltaics. Relevant researches develop rapidly due to the excellent properties of MAPbI3, such as high charge mobility, suitable band gap, and long carrier diffusion length. However, the instability of MAPbI3 has been a key issue hindering practical application. Here, we present in situ spectroscopic ellipsometry measurement to monitor the thermal degradation process of MAPbI3. The dynamic evolution of dielectric functions of the as-prepared MAPbI3 films through degradation is extracted by an effective medium approximation model fitting the ellipsometry spectrum. The content proportion of MAPbI3 and PbI2 is also obtained from the modeling results. The thickness of the film decreases in two steps corresponding to the degradation and melting–recrystallization process. The current work shows that ellipsometry provides a potentially fast and non-damage tool to monitor the degradation process and to determine the degree of degradation for MAPbI3 perovskite films. Our work exhibits the first in situ monitoring of the optical properties through the degradation process of MAPbI3 films, which can be consulted for further testing of the degree of degradation for MAPbI3 solar cells and improving the stability of MAPbI3.
研究领域:
材料科学
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光伏技术
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Scientific Reports
·
2017
·Vol. 7
·期 1
·1-9
·
IF 4.259
Zhang Hao,Tao Mian,Gao Baizhi,Chen Wei,Li Qi,Xu Qingyu,Dong Shuai
The fabrication of high-quality organic-inorganic hybrid halide perovskite layers is the key prerequisite for the realization of high efficient photon energy harvest and electric energy conversion in their related solar cells. In this article, we report a novel fabrication technique of CH 3 NH 3 PbI 3 layers based on high temperature chemical vapor reaction. CH 3 NH 3 PbI 3 layers have been prepared by the reaction of PbI 2 films which were deposited by pulsed laser deposition, with CH 3 NH 3 I vapor at various temperatures from 160 °C to 210 °C. X-ray diffraction patterns confirm the formation of pure phase, and photoluminescence spectra show the strong peak at around 760 nm. Scanning electron microscopy images confirm the significantly increased average grain size from nearly 1 μm at low reaction temperature of 160 °C to more than 10 μm at high reaction temperature of 200 °C. The solar cells were fabricated, and short-circuit current density of 15.75 mA/cm 2 , open-circuit voltage of 0.49 V and fill factor of 71.66% have been obtained.
研究领域:
材料科学
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能源技术
·
光电转换
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2015
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IF 2.711
Ying Zhao,Jian Liu,Xinrong Lu,Yandong Gao,Xiaozeng You,Xiangxing Xu
Perovskite-structured organic–inorganic materials such as CH 3 NH 3 PbI 3 are attracting much interest in the scientific community because of their abilities to function as revolutionary light harvesters and charge transfer materials for solar cells. To achieve high power conversion efficiency (PCE), it is critical to optimize the perovskite film layer. This paper reports the temperature and concentration controls on the two-step solution process. A diffusion-controlled growth mechanism is proposed for this process in tuning the morphology and purity of the perovskite film, which are proven to be important factors contributing to the photovoltaic performance. The highest PCE of 11.92% is achieved with an optimized perovskite crystal size of ∼150 nm and an appropriate amount of residual PbI 2 . This study sheds light on the design and fabrication of highly efficient, low-cost, solution-processed perovskite solar cells.
研究领域:
材料科学
·
太阳能电池技术
✓ 已验证
DOI
高影响因子
Nanoscale
·
2016
·Vol. 8
·期 12
·6600-6608
·
IF 7.76
Shimao Wang,Weiwei Dong,Xiaodong Fang,Qingli Zhang,Shu Zhou,Zanhong Deng,Ruhua Tao,Jingzhen Shao,Rui Xia,Chao Song,Linhua Hu,Jun Zhu
The role of remnant PbI2 in CH3NH3PbI3 films is still controversial, some investigations have revealed that the remnant PbI2 plays a passivation role, reduces the charge recombination in perovskite solar cells (PSCs), and improves the performance of PSCs, but the opposing views state that remnant PbI2 has no passivation effect and it would deteriorate the stability of the devices. In our investigation, the CH3NH3PbI3 films have been prepared by a two-step spin-coating method and the content of the remnant PbI2 in CH3NH3PbI3 films has been tuned by varying the preparation temperature. It has been found that increasing the heating temperature could increase the coverage of spin-coated PbI2 films, which has led to high coverage CH3NH3PbI3 films and more remnant PbI2 in CH3NH3PbI3 films, and as a result, the performance of PSCs was enhanced obviously and the maximum power conversion efficiency of 14.32 ± 0.28% was achieved by the PSCs prepared at 130/120 °C (PbI2 films were heated at 130 °C and CH3NH3PbI3 films were heated at 120 °C). Furthermore, the dark current, electrochemical impedance spectroscopy and time-resolved fluorescence emission decay measurements revealed that the charge recombination in PSCs has been gradually suppressed and the fluorescence emission lifetime has gradually increased with the content of remnant PbI2 increasing. Thus, the passivation effects of the unreacted and decomposed PbI2 in improving the performance of PSCs have been confirmed unquestionably.
研究领域:
材料科学
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光伏技术
·
太阳能
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF PHYSICS D-APPLIED PHYSICS
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2019
·Vol. 53
·期 7
·075101
·
IF 2.829
Y Y Wang,L T Li,X Jiang,J B Wang,R L Lai,X Y Qiu
Electric field-induced drift of ions or charged defects in organic–inorganic hybrid perovskite materials generally results in distinct current–voltage hysteresis, opening up a new era in the development of low-cost resistive switching memory and neural synapse devices. Here, a new type of resistive switching memory cell based on NiO-buffered CH3NH3PbI3 films is prepared by a solution method. It exhibits stable and low voltage bipolar resistive switching behaviors: switching voltages lower than ±0.5 V, an ON/OFF ratio higher than 103, and a reversible current–voltage loop of more than 400 cycles in air ambient. Both 'iodine-vacancy conductive filaments' and the 'interfacial p–n junction effect' are responsible for the improved resistive switching properties. This work establishes the potential for application in low operation voltage organic–inorganic hybrid perovskite resistive switching devices.
研究领域:
材料科学
·
电气工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）