Perovskite Single Crystals with Self‐Cleaning Surface for Efficient Photovoltaics

Metal halide perovskite single crystals are promising for diverse optoelectronic applications. As a universal issue of solution-grown perovskite single crystals, surface contamination causes adverse effect on material properties and device performance. Herein, learning from the self-cleaning effect of lotus leaf, we address the surface contamination issue by introducing an amphiphilic long-chain organic amine into the perovskite crystal growth solution. Self-assembly of CTAC provides a hydrophobic crystal surface, inducing spontaneous removal of residual growth solution, which results in clean surface and better optoelectronic properties of perovskite single crystals. An impressive efficiency of 23.4 % is obtained, setting a new record for FA