LAUSR

The electron transport layer (ETL) places an important role in improving the performance of flexible perovskite solar cells (F-PSCs). Herein, w e demonstrate a room temperature processed SnO2 :OH ETL that exhibits reduced defect density, in particular lower oxygen vacancy concentration with better energy band alignment and more wettable surface for quality perovskite deposition. More importantly, an efficient electron transfer channel is produced between the ETL and the perovskite layer due to the formation of hydrogen bonds at the interface, resulting in enhanced electron extraction from the perovskite. As a result, the efficiency of a large area (36.50 cm2 ) flexible perovskite solar module based on MAPbI3 is increased to as high as 18.71%, to the best of o ur knowledge, this is the highest PCE value reported for flexible perovskite solar modules up to date. In addition, it exhibits high durability while maintaining over 83% of its initial PCE after flexing test cycles. Further, F-PSCs with SnO2 :OH show remarkably long-term stability, owing to a high quality of the perovskite film and a strong coupling between the SnO2 :OH and perovskite layer caused by hydrogen bonds,, which successfully inhibits moisture permeation. This article is protected by copyright. All rights reserved.