Modulation of crystallization dynamics via multifunctional additive engineering to achieve high-performance perovskite solar cells

Abstract

Modulating the crystallization dynamics of perovskite is critical for achieving high-quality and defect-less films for perovskite solar cells (PSCs). We applied a novel multifunctional additive, namely methyl hydrazine-1-carbohydrazonothioate hydroiodide (MHCT-HI), in inverted solar cells. The additive can effectively accelerate nucleation and slow down crystal growth, which lead to large and homogeneous perovskite grains with stable morphology. Intriguingly, according to Backscattered Electron Detection-Contrast (BED-C) characterization, we observed the re-distribution of PbI₂ content to grain boundaries, which assists in defect passivation and inhibits degradation. Consequently, the device achieved a significantly improved power conversion efficiency (PCE) of 25.04% and superior long-term stability. This study emphasizes the potential of MHCT-HI in modulating crystallization dynamics, which could be broadly applied to other inverted PSCs. We also highlight the effectiveness of using BED-C characterization in visualizing the distribution of PbI₂ within perovskite films.