Nicotinamide‐Modified PEDOT:PSS for High Performance Indoor and Outdoor Tin Perovskite Photovoltaics

Tin perovskites are generally considered as promising candidates to solve the issue of toxicity for lead perovskites. However, the open‐circuit voltage ( V OC ) of tin perovskite solar cells is usually lower than expected. Herein, the hole‐transporting layer of PEDOT:PSS is treated with nicotinamide, and the tin perovskite active layer is deposited on the treated film to prepare a perovskite photovoltaic device. The fabricated device presented an increased V OC from 0.63 to 0.82 V, yielding an improved power conversion efficiency (PCE) increased from 4.77% to 8.28%. More importantly, under the weak light (1000 lux) irradiation of a simulated indoor light source, the device presented a PCE as high as 14.40%, which is the highest indoor efficiency for tin‐based perovskite photovoltaics reported so far. The promising indoor performance of tin perovskite photovoltaics paves a new way to fabricate eco‐friendly indoor photovoltaics by using lead‐free tin perovskites.