Halide perovskite films processed from solution at low-temperature offer promising opportunities to make flexible solar cells. However, the brittleness of perovskite films is an issue for mechanical stability in flexible devices. Herein, photo-crosslinked [6,6]-phenylC61 -butyric oxetane dendron ester (C-PCBOD) is used to improve the mechanical stability of methylammonium lead iodide (MAPbI3 ) perovskite films. Also, it is demonstrated that C-PCBOD passivates the grain boundaries, which reduces the formation of trap states and enhances the environmental stability of MAPbI3 . Thus, MAPbI3 perovskite solar cells are prepared on solid and flexible substrates with record efficiencies of 20.4% and 18.1%, respectively, which are among the highest ever reported for MAPbI3 on both flexible and solid substrates. The result of this work provides a step improvement toward stable and efficient flexible perovskite solar cells.
Keywords: flexible solar cells; mechanical stability; perovskite solar cells; photo-crosslinking.
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