Perovskite solar cells fabricated under ambient air at room temperature without any post-treatment

Abstract Solution process is the widely used simple way to prepare perovskite films for solar cells. For films fabricated from precursors with conventional solvents (DMF, DMSO or GBL), stable intermediate phase is formed in the films after spin-coating. Thermal annealing or other processes are required to transform this intermediate phase into perovskite crystal. Herein, we prepared perovskite films by a single spin-coating process without any post-treatment (post-treatment free process (PTFP)) based on perovskite precursor using 2-methoxyethanol (2-ME) as solvent. For the film obtained from 2-ME solution, a completely transformed perovskite film could been obtained immediately after spin-coating in glove box or under ambient air at room temperature. By using PTFP method with 2-ME solution, power conversion efficiency of 12.95% in glove box and 12.77% under ambient air have been achieved for planar perovskite solar cells (ITO/PEDOT:PSS/perovskite/PC61BM/BCP/Ag) without any assistance processes at room temperature. This very simple fabrication process of PTFP for perovskite films can be easily adopted in roll-to-roll production in commercialization.