Unveiling the Single-Solvent Vacuum-Flash Process for High-Efficiency Perovskite Solar Cells

Abstract

High-crystallinity perovskite films with low trap density are a prerequisite for realizing high-performance perovskite solar cells (PSCs). Here, we present a straightforward single-solvent vacuum-flash (SSVF) method for fabricating high-quality perovskite films using a simplified, single-solvent precursor system(e.g., N,N-Dimethylformamide (DMF), dimethylacetamide (DMAC), and γ-valerolactone (GVL)). By creating a low temperature (LT) and vacuum environment for the precursor wet film, the SSVF method enables precise regulation of solvent evaporation dynamics, resulting in the formation of highly compact perovskite films with low trap densities. As a result, the PSCs fabricated via this method achieve a champion power conversion efficiency (PCE) of 26.93%, along with a certified PCE of 26.78% (certified steady-state efficiency of 26.39%). This performance ranks among the highest efficiencies ever reported for any vacuum-flash (VF)-based technique. Furthermore, owing to the enhanced phase stability of the perovskite film prepared via the SSVF method, the resulting PSC exhibits excellent operational durability, maintaining over 94% of its initial efficiency after 1000 hours of continuous operation.