Alleviating Interfacial Recombination of Heterojunction Electron Transport Layer via Oxygen Vacancy Engineering for Efficient Perovskite Solar Cells Over 23%

Electron transport layer (ETL) is pivotal to charge carrier for PSCs reach the Shockley–Queisser limit. This study provides a fundamental understanding of heterojunction electron layers (ETLs) at atomic level stable and efficient perovskite solar cells (PSCs). The bilayer structure an ETL composed SnO2 on TiO2 was examined, revealing critical factor limiting its potential obtain performance. Alteration oxygen vacancies in underlayer via annealing process found induce manipulated band offsets interface between layers. In-depth electronic investigations elucidate importance properties apparent correlation hysteresis phenomena, including current density–voltage (J–V) curves, appears as function type alignment. Density functional theory calculations reveal intimate relationship vacancies, deep trap states, efficiency formation cascade alignment control over enhances device performance suppresses hysteresis. Optimal exhibits power conversion (PCE) 23.45% with open-circuit voltage (Voc) 1.184 V, showing better stability under maximum point tracking compared staggered one-sun continuous illumination.