Anion-stabilized precursor inks toward efficient and reproducible air-processed perovskite solar cells

Despite the outperforming power conversion efficiency of low-temperature and solution-processed perovskite solar cells (PSCs) realized over the past decades, the undesirable stability from precursor inks to resultant devices and harsh preparation requirements still restrain their industrial production and practical deployment. Herein, an anion stabilization strategy is developed to achieve the comprehensive durability of perovskite photovoltaics throughout the whole two-step air-processed procedure. The effect of interionic bonding strengths on the ink properties, film crystallization, and photovoltaic performances is in-depth explored and revealed. The pseudohalide bis(trifluoromethanesulfonyl)imide ions (TFSI${}^{-}$) not only improve the dispersion and stabilities of lead polyhalides and organic salt inks via strong electron-withdrawing/donating chemical sites, but also realize high composition uniformity and preferential crystal growth of subsequent deposited perovskite layers by tuning the precursor reactivity and surface absorption. Ultimately, the optimizing PSCs deliver a superior efficiency of 24.16%, accompanied by notably improved long-term stability toward extreme environmental and mechanical stimuli with lead leakage suppression. This work opens up a promising avenue toward reproducible air preparation of highly efficient, stable, and environmentally friendly perovskite optoelectronic devices via precise modulation of precursor properties. (© 2024 Wiley‐VCH GmbH)