Rapid Surface Reconstruction in Air-Processed Perovskite Solar Cells by Blade Coating.

Blade coating has been developed to be an essential technique for large-area fabrication of perovskite solar cells (PSCs). However, effective surface treatment of the perovskite layer, which is a critical step for improving PSC performance, remains challenges during blade coating due to the short interaction time between the modification solution and the perovskite layer, as well as the limited selection of available organic solvents. In this study, a novel modifier N, N-diphenylguanidine monohydrobromide (DPGABr) dissolved in acetonitrile (ACN) is blade-coated on the surface of a mixed perovskite film in air to reconstruct the perovskite surface in hundreds of milliseconds. We find that the solvent ACN rapidly dissolves organic iodide of the perovskite layer and leads to a PbI 2 -rich surface, providing reactive sites for DPGABr to form a thin DPGABr/PbI 2 complex layer. This surface reconstruction can effectively passivate defects and induce n-type doping on the perovskite surface to facilitate electron transfer. The resultant devices show a relative enhancement of 15% in the average power conversion efficiency. More importantly, the devices with the surface reconstruction show outstanding long-term stability and the devices performances undergo negligible degradation even after one-year storage in air. This study presents a convenient and effective approach for improving the performance of blade-coated PSCs prepared in air. This article is protected by copyright. All rights reserved.