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The Effect of Stoichiometry on the Stability of Inorganic Cesium Lead Mixed-Halide Perovskites Solar Cells

Authors :
Ma, Qingshan
Huang, Shujuan
Chen, Sheng
Zhang, Meng
Lau, Cho Fai Jonathan
Lockrey, Mark N.
Mulmudi, Hemant K.
Shan, Yuchao
Yao, Jizhong
Zheng, Jianghui
Deng, Xiaofan
Catchpole, Kylie
Green, Martin A.
Ho-Baillie, Anita W. Y.
Source :
The Journal of Physical Chemistry - Part C; 20240101, Issue: Preprints
Publication Year :
2024

Abstract

Metal halide perovskite solar cells that use the inorganic cation Cs have been shown to have better thermal stability than the organic cation containing counterparts, and CsPbI2Br has a more suitable (lower) band gap than CsPbIBr2as a photovoltaic energy harvesting material. However, increase in iodine content reduces structural stability due to the preference toward the non-perovskite orthorhombic phase when the film is exposed to air. In this work, the effect of varying stoichiometry of CsPbI2Br perovskite on film quality such as the grain size, presence of impurities and nature of impurity grains, photoluminescence, morphology, and elemental distribution are studied. Details on how to vary the stoichiometry during the dual source thermal evaporation process are reported. It is found that the air stability of CsPbI2Br film correlates with the CsBr-to-PbI2deposition rate ratio, in which the CsBr-rich CsPbI2Br is the most stable upon air exposure, while the stoichiometrically balanced CsPbI2Br perovskite film gives the best photovoltaic performance. The encapsulated device maintains 90% of the initial performance after 240 h damp and heat test at 85 °C and 85% relative humidity.

Details

Language :
English
ISSN :
19327447 and 19327455
Issue :
Preprints
Database :
Supplemental Index
Journal :
The Journal of Physical Chemistry - Part C
Publication Type :
Periodical
Accession number :
ejs43010226
Full Text :
https://doi.org/10.1021/acs.jpcc.7b06268