Science News: 2021 ACS Energy Lett. What is the key to making stable FAPI?

　　In September 2021, ACS Energy Letters (IF 19.05) journal published a study by Iván Mora-Seró et al. The demand for perovskite-based photovoltaic devices urgently needs to be manufactured under ambient atmosphere, not limited to low relative humidity (RH) conditions.

　　Here, FAPI perovskite solar cells (PSCs) are made of N-methylpyrrolidone (NMP). Through experiments with solar simulators and other instruments, the author found that pure FAPI perovskite solar cell (PSC) manufactured under ambient air is better than under nitrogen, and the long-term stability of the device is significantly improved.

　　The T80 parameter (that is, the time for the efficiency to drop to 80% of the initial value) has been extended from 21 (in N2) to 112 days (in the environment). If PbS quantum dots (QDs) are used as additives in the air, the time will increase to 145 days. In addition, with the addition of methylammonium chloride (MACl) , the power conversion efficiency (PCE) reaches 19.4%, and the device can maintain 100% of the original performance for at least 53 days. In FAPI films prepared in ambient conditions, the existence of Pb-O bonds would block the propagation of α- to δ-FAPI phase conversion.