Amidino-Based Buried Interface Optimization for Efficient and Stable Inverted Perovskite Solar Cells

Driven by the implementation of self-assembled monolayers (SAMs), power conversion efficiencies (PCEs) of inverted perovskite solar cells (PSCs) have surged to approximately 27% in recent years. Nevertheless, pristine SAMs are often insufficient for effectively mitigating defects located at the buried interface. Consequently, modifying SAMs to optimize the buried interface is essential for promoting superior perovskite crystallization and boosting device performance. Herein, we propose an innovative passivation approach targeting the buried interface by employing 1,4-benzene diammonium iodide (PDAI₂) and a tailored amidine derivative, 1,4-benzenedicarboximidamide hydroiodide (PDAII₂). Relative to the control and PDAI₂-treated devices, PDAII₂ significantly improves the crystallization at the SAMs/perovskite interface. Furthermore, the energy level alignment at the buried interface has also been substantially enhanced by PDAII₂. Consequently, a champion PCE of 25.53% with exceptional environmental stability has been achieved in PDAII₂-treated PSCs.