Defect passivation with bromine template for efficient perovskite solar cells.

Interfacial modification is an effective method to improve the performance of perovskite solar cells (PSCs). However, defects in SnO 2 itself and interfacial defects with perovskite (PVK) lead to the limited performance of PSCs. In this study, 3, 5-dibromobenzoic acid (3,5-DBBA) material was added at the interface between electron transport layer (ETL)and perovskite absorption layer. It was found that Br in 3,5-DBBA can passivate the oxygen vacancies and uncoordinated Sn4+ defects in SnO 2 , and optimize the interface contact between ETL and perovskite film, inhibit the non-radiative recombination of charge carriers, and improve the carrier lifetime and extraction yield. Br is also able to interact with the perovskite lattice to passivate Pb2+ defects and regulate the crystal growth of the perovskite. The open circuit voltage of perovskite solar cells was increased from 1.12 V to 1.16 V, and the power conversion efficiency was increased from 19.19 % to 22.27 %. The bromine templates strategy can also effectively improve the stability of PSCs. It provides a new strategy for realizing high performance perovskite solar cells. [ABSTRACT FROM AUTHOR]