Proceedings of nanoGe International Conference on Perovskite Solar Cells, Photonics and Optoelectronics (NIPHO19)
DOI: https://doi.org/10.29363/nanoge.nipho.2019.015
Publication date: 21st November 2018
Perovskite solar cells demonstrated impressive power conversion efficiencies of >22%, while their practical application is hampered by poor stability of the active materials. Functional layers of perovskite solar cells have to sustain electric fields generated by built-in and light-induced potentials. Otherwise, the electrochemical degradation of active or charge transport layer materials would ruin the solar cell performance.
In this work, we report a systematic comparative study of the electrochemical stability of a series of hybrid and all-inorganic lead halide based perovskite materials - MAPbI3, MAPbBr3, FAPbI3, FAPbBr3, CsPbBr3, CsPbI2Br. Thin films of these materials were exposed to the potentiostatic polarization under anoxic conditions using the lateral and vertical two-electrode device architectures. We have shown that polarization leads to the appearance of the field-induced gradients in the chemical composition of the films as revealed by PL and Kelvin probe microscopy and ToF-SIMS. The effects of the potentiostatic polarization of the solar cells under forward and reversed bias on their photovoltaic performance will be also discussed and interpreted using results of the light beam induced current (LBIC) mapping. Analysis of the obtained data allowed us to correlate the chemical composition of the perovskite materials with their electrochemical stability, which might guide further design of stable light absorbers for future generation photovoltaics.