Realizing a dual passivation by introducing hydrogen bonding for efficient and stable perovskite solar cells

The interface defects and loss of organic cations critically affect the performance and stability of perovskite solar cells (PSCs). Here, we adopted a dual passivation strategy, using potassium trifluoroacetic acid (KTFA) as the surface treatment agent for the tin dioxide (SnO 2 ) electron transport layer (ETL). The fluorine interacts with organic cations in perovskite to form N-H…F hydrogen bonding which inhibit the organic ion migration as well as improve the quality of interface contact between perovskite and ETL. In addition, the lattice oxygen ratio in SnO 2 increased after the modification indicating the ETL defects are effectively passivated. Consequently, the power conversion efficiency of the device based on the KTFA passivated SnO 2 is enhanced from 21 % to 23.05 % and the stability is also improved. • Introduction of KTFA enables dual passivation at the SnO₂/perovskite interface. • N–H···F hydrogen bonding suppresses ion migration and defect generation. • Improved energy level alignment facilitates electron transport and enhances Voc. • The device achieved a PCE of 23.05 % with significantly improved stability.