Optimizing ETL/CsPbBr <sub>3</sub> buried interface contact for enhanced efficiency and stability of inorganic perovskite solar cells
Siyu Zhang, Xing Guo, Yumeng Xu, Yong Jiao, Zhenhua Lin, Jincheng Zhang, Jianyong Ouyang, Lixin Guo, Yue Hao, Jingjing Chang
Abstract
Abstract CsPbBr 3 perovskite solar cells (PSCs) have attracted significant interest for their remarkable stability under high temperatures and humidity. However, challenges such as energy loss at the CsPbBr 3 /oxide buried interface and imperfect band alignment have impeded further efficiency enhancements. In this study, TiO 2 , SnO 2 , or ZnO was employed as electron transport layer (ETL) materials, respectively, in CsPbBr 3 ‐based PSCs to optimize the band alignment at the ETL/CsPbBr 3 interface and enhance the film quality of CsPbBr 3 materials. The research findings indicate that the power conversion efficiency (PCE) of PSCs is influenced by the choice of ETL material. Specifically, TiO 2 ‐based PSCs achieved a PCE of 10.37% efficiency, higher than SnO 2 ‐ or ZnO‐based PSCs. This disparity in PCE can be attributed to variations in open‐circuit voltage, which stem from different band alignments at the ETL/CsPbBr 3 interface. Notably, superior photovoltaic performance was consistently observed in TiO 2 ‐based PSCs due to the substantial conduction band offset (∆ E c ) at the TiO 2 /CsPbBr 3 interface and the high quality of the CsPbBr 3 film. This not only enhances electron extraction at the TiO 2 /CsPbBr 3 interface but also diminishes non‐radiative recombination at the interface, as confirmed by density functional theory (DFT) calculations and experiments. Furthermore, photodetectors (PDs) based on TiO 2 /CsPbBr 3 heterojunction exhibit high photoresponse and photodetectivity. In conclusion, this study underscores the critical importance of the buried interface contact in CsPbBr 3 and offers a direct approach for fabricating efficient and stable inorganic PSCs and PDs.