Decoding Charge Recombination and Extraction at Perovskite Interfaces with Transient Photoluminescence

Understanding charge carrier dynamics at buried interfaces is pivotal for the rational design of high-performance perovskite solar cells (PSCs). This study presents a novel methodology combining transient photoluminescence spectroscopy with a differential equation-based analytical framework to elucidate the interplay between charge extraction and recombination processes at perovskite interfaces. The results demonstrate that the superior efficiency of self-assembled monolayer (SAM)-based devices, in comparison to conventional semiconductor thin-film-based hole transport layers, is primarily attributed to a substantially reduced defect-mediated recombination rate. While the hole extraction efficiency of SAMs is relatively low, particularly under low carrier concentrations, the findings underscore that excessive optimization of charge extraction is not the primary determinant of device performance. Instead, precise regulation of interfacial defects and mitigation of Shockley-Read-Hall (SRH) recombination emerge as critical factors for performance enhancement. These insights provide a robust framework for the interface design and optimization of PSCs. Moreover, the proposed approach serves as a non-contact, high-throughput tool for evaluating the quality of buried interfaces, facilitating accelerated material discovery, and advancing energy research.