Enhanced Performance of Fabricated Iodine‐Rich Perovskite Solar Cells via Reverse‐Biasing

Perovskite solar cells (PSCs) are undergoing rapid development and exhibit considerable potential for commercialization. Recent studies have shown that reverse bias can improve the open‐circuit voltage ( V OC ) of PSCs by ≈0.06 V due to the migration of iodine ions filling vacancies at the electron transport layer (ETL)/perovskite interface. It can be deduced that in iodine‐rich PSCs, the potential for reverse‐biasing to enhance V OC is limited due to the suppression of iodine vacancies by excess iodine atoms. This work confirms that, in iodine‐rich PSCs, reverse bias has a minimal effect on V OC , but leads to a ≈3.9% increase in short‐circuit current density ( J SC ), from 25.40 to 26.40 mA/cm 2 , and an enhancement of ≈3.2% in power conversion efficiency from 23.00% to 23.74%. The improved J SC can be attributed to reduced carrier recombination near the ETL/perovskite interface, as evidenced by enhanced external quantum efficiency and increased recombination resistance in the short‐wavelength region. These insights suggest a practical posttreatment strategy for high‐performance PSCs.