Flexible Perovskite Solar Cells Fabricated by Gradient Heat Treatment Process
Flexible perovskite solar cells (F-PSCs) are attracting tremendous research interest due to their light weight and flexibility, etc. However, the poor quality of perovskite film caused by deformation of flexible substrate during general heat treatment process is a hinder to fabricate high efficiency flexible cells. Here, a simple gradient heat treatment (GHT) process is developed to effectively improve the crystal quality of perovskite film and the efficiency of F-PSCs. The results show that a smaller temperature fall-off gradient will be benefit to the secondary growth of perovskite films, which helps to further enhance the crystalline quality. Compared with the conventional method, the power conversion efficiency (PCE) of F-PSCs fabricated by a GHT process with relatively small gradient has been significantly improved by 31%, and the maximum PCE has increased to 17.37%. This work provides a new idea for ameliorating the quality of perovskite film and enhancing the performance of F-PSCs.