Solvent‐Assisted Low‐Temperature Crystallization of SnO2 Electron‐Transfer Layer for High‐Efficiency Planar Perovskite Solar Cells

• Published in: Advanced functional materials Vol. 29; no. 30
• Main Authors: Chen, Cong, Jiang, Yue, Guo, Jiali, Wu, Xiayan, Zhang, Wenhui, Wu, Sujuan, Gao, Xingsen, Hu, Xiaowen, Wang, Qianming, Zhou, Guofu, Chen, Yiwang, Liu, Jun‐Ming, Kempa, Krzysztof, Gao, Jinwei
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 25.07.2019
• Subjects: Butanol; Crystallization; Efficiency; electron transfer layers; flexible electronics; Low temperature; low‐temperature SnO2; Materials science; perovskite solar cells; Perovskites; Photovoltaic cells; Solar cells; Solvents; Substrates; Tin dioxide
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201900557

A high‐quality polycrystalline SnO2 electron‐transfer layer is synthesized through an in situ, low‐temperature, and unique butanol–water solvent‐assisted process. By choosing a mixture of butanol and water as a solvent, the crystallinity is enhanced and the crystallization temperature is lowered to 130 °C, making the process fully compatible with flexible plastic substrates. The best solar cells fabricated using these layers achieve an efficiency of 20.52% (average 19.02%) which is among the best in the class of planar n–i–p‐type perovskite (MAPbI3) solar cells. The strongly reduced crystallization temperature of the materials allows their use on a flexible substrate, with a resulting device efficiency of 18%. In situ synthesis of polycrystalline SnO2 electron‐transfer layers (ETLs) at temperatures as low as 130 °C is developed. The best efficiency of devices fabricated using these ETLs is up to 20.52% for those based on glass and 18% for those based on a flexible substrate, among the best for planar n–i–p‐type perovskite (MAPbI3) solar cells.