Sulfonyl passivation through synergistic hydrogen bonding and coordination interactions for efficient and stable perovskite solar cells

Aiming to regulate crystallization and reduce defects of perovskite films, an organic small molecule with sulfonyl, 3-ethylbenzo[d]isothiazole 1,1-dioxide (PSAD), is introduced into perovskite precursor solution. A variety of characterization studies (nuclear magnetic resonance, Fourier transform infrared and X-ray photoelectron spectra) and density functional theory calculations are conducted to reveal the hydrogen bonding and coordination interactions between PSAD and perovskite. As a result, a perovskite film with large grains and reduced defects is obtained, along with the lessened non-radiation recombination, decreasing hole extraction energy loss, and ameliorative electron extraction. All these efficacies contribute to the enhanced efficiency and stability of the PSAD-treated devices. Our chemical strategy can help to explore the mechanism behind passivation to improve perovskite photovoltaics.