Spontaneous bifacial capping of perovskite film for efficient and mechanically stable flexible solar cell

Flexible perovskite solar cells (F-PSCs) are appealing for their flexibility and high power-to-weight ratios. However, the fragile grain boundaries (GBs) in perovskite films can lead to stress and strain cracks under bending conditions, limiting the performance and stability of F-PSCs. Herein, we show that the perovskite film can facilely achieve in situ bifacial capping via introducing 4-(methoxy)benzylamine hydrobromide (MeOBABr) as the precursor additive. The spontaneously formed MeOBABr capping layers flatten the grain boundary grooves (GBGs), enable the release of the mechanical stress at the GBs during bending, rendering enhanced film robustness. They also contribute to the reduction of the residual…

• NN
  National Natural Science Foundation of China

  Awards: 61974106, No. 52103229, 52103229
• WU
  Wuhan University
• BA
  Basic and Applied Basic Research Foundation of Guangdong Province

  Award: 2021A1515110632