Substrate-dependent gamma-ray irradiation-induced degradation in perovskite solar cells for space applications

초록

Perovskite solar cells (PSCs) are promising candidates for next-generation space-based photovoltaics owing to their high efficiency and compatibility with lightweight flexible form factors. Solar cells in space environments are exposed to ionizing radiation that accumulates as a total ionizing dose (TID), making radiation tolerance a critical performance metric for PSCs. Although radiation-induced photodarkening of the transparent substrate can dominate the apparent response of a PSC to gamma irradiation, this contribution has rarely been isolated during device-level evaluations of radiation tolerance. This study accordingly investigated the photovoltaic characteristics of n-i-p triple-cation PSCs subjected to various TIDs of Co-60 gamma-ray irradiation (0, 1, 5, 25, and 50 kGy) with four different transparent substrates comprising soda-lime, anti-reflective soda-lime, borosilicate, or highpurity quartz glass. Optical measurements and external quantum efficiency spectroscopy of the substrates revealed a strong spectral correspondence between substrate photodarkening and short-circuit current density loss. The photovoltaic characteristics of the quartz-based PSCs remained nearly unchanged after irradiation at any dose, whereas those of the glass-based PSCs exhibited pronounced radiation dose-dependent degradation. By contrast, analyses of the perovskite films indicated that phase integrity and morphology were generally preserved with only minor changes after irradiation. These results highlight the importance of substrate selection and component-level attribution during the radiation testing of PSCs and provide a practical framework for developing more reliable methods of evaluating PSCs in radiation-exposed applications, such as in space, where TID accumulation represents a critical reliability constraint.

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