High-Quality Thiophene-Based Two-Dimensional Perovskite Films Prepared with Dual Additives and Their Application in Solar Cells

This study explores the optimization of (TMA)₂MA₄Pb₅I₁₆ perovskite films by regulating the film quality through the addition of MACl and MAAc additives. We found that adding MACl resulted in a film of larger grains with a power conversion efficiency (PCE) of 5.34%, while excessive MACl led to the formation of low-dimensional phases. Adding 7.5% MAAc improved the film quality with a PCE of 5.64%, although excessive MAAc induces pores and smaller grains. To address these issues, we proposed the combined use of MACl and MAAc additives, resulting in films with a larger grain size, smoother surface, and denser structure. Remarkably, the addition of MAAc + MACl achieved a champion PCE of 8.86% with good reproducibility. Mechanism studies revealed that TMA and MAAc formed a stable complex with PbI₂ in solution, disrupting nucleation laws and promoting the formation of nuclei, leading to denser films with smaller grains. Additionally, the MACl treatment effectively promoted grain growth, resulting in high-quality films. This study presents novel insights into dual additive usage and their role in film crystallization, offering valuable guidance for the preparation of high-performance perovskite films.