Suppressing Interfacial Charge Recombination in Electron‐Transport‐Layer‐Free Perovskite Solar Cells to Give an Efficiency Exceeding 21

• Published in: Angewandte Chemie International Edition Vol. 59; no. 47; pp. 20980 - 20987
• Main Authors: Wu, Wu‐Qiang, Liao, Jin‐Feng, Zhong, Jun‐Xing, Xu, Yang‐Fan, Wang, Lianzhou, Huang, Jinsong
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 16-11-2020
• Edition: International ed. in English
• Subjects: amorphous metal oxyhydroxide; charge recombination; charge tunneling; Efficiency; Electron tunneling; interfacial modification; Interlayers; Metal oxides; perovskite solar cells; Perovskites; Photovoltaic cells; Recombination; Solar cells; Titanium dioxide
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202005680

The performances of electron‐transport‐layer (ETL)‐free perovskite solar cells (PSCs) are still inferior to ETL‐containing devices. This is mainly due to severe interfacial charge recombination occurring at the transparent conducting oxide (TCO)/perovskite interface, where the photo‐injected electrons in the TCO can travel back to recombine with holes in the perovskite layer. Herein, we demonstrate for the first time that a non‐annealed, insulating, amorphous metal oxyhydroxide, atomic‐scale thin interlayer (ca. 3 nm) between the TCO and perovskite facilitates electron tunneling and suppresses the interfacial charge recombination. This largely reduced the interfacial charge recombination loss and achieved a record efficiency of 21.1 % for n‐i‐p structured ETL‐free PSCs, outperforming their ETL‐containing metal oxide counterparts (18.7 %), as well as narrowing the efficiency gap with high‐efficiency PSCs employing highly crystalline TiO2 ETLs.
A non‐annealed, ultrathin, amorphous metal oxyhydroxide was introduced to suppress interfacial charge recombination and reduce energy loss in electron‐transport‐layer (ETL)‐free perovskite solar cells. The cells achieve a record efficiency of 21.1 %, outperforming their ETL‐containing metal oxide counterparts (18.7 %).