γ‑Ray-Induced Degradation in the Triple-Cation Perovskite Solar Cells

• Published in: The journal of physical chemistry letters 2019-02, Vol.10 (4), p.813-818
• Main Authors: Boldyreva, Aleksandra G., Akbulatov, Azat F., Tsarev, Sergey A., Luchkin, Sergey Yu, Zhidkov, Ivan S., Kurmaev, Erst Z., Stevenson, Keith J., Petrov, Vladimir G., Troshin, Pavel A.
• Format: Article
• Language: English
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.8b03222

We report on the impact of γ radiation (0–500 Gy) on triple-cation Cs0.15MA0.10FA0.75Pb­(Br0.17I0.83)3 perovskite solar cells. A set of experiments was designed to reveal the individual contributions of the hole-collecting bottom electrode, perovskite absorber, and electron transport layer (ETL) to the overall solar cell degradation under radiation exposure. We show that the glass/ITO/PEDOT:PSS hole-collecting electrode withstands a 500 Gy dose without any losses in the solar cell performance. In contrast, the perovskite absorber films and PC61BM ETL are very sensitive to γ rays, as can be concluded from the radiation-induced decay of the solar cell efficiency by ∼32–41%. Red shift of the perovskite emission bands and strong enhancement of the photoluminescence suggest that γ rays induce phase segregation of iodine-rich and bromine-rich domains, which represents the first reported example of the radiation-induced halide phase separation in perovskite films. The degradation pathway revealed here emphasizes the need for developing a new generation of metal halide absorbers and ETL materials with improved radiation stability to enable potential space applications of perovskite photovoltaics.