In-plane uniaxial crystal growth in CH3NH3PbI3 bar-coated thin film by evaporation-site-controlled annealing

Abstract In the thin film fabrication of a typical organic–inorganic halide perovskite material, CH 3 NH 3 PbI 3 (MAPbI 3 ), by bar-coating, thermal conversion from its precursor to MAPbI 3 was focused on, and an evaporation-site-controlled annealing method was proposed. The crystal grain size of MAPbI 3 changed depending on the sweep speed of a cover plate set above the precursor liquid films. The crystallinity of the MAPbI 3 thin film was clarified by analyzing electron backscatter diffraction. The typical inverted-type solar cells with the MAPbI 3 thin films prepared by evaporation-site-controlled annealing were fabricated, and the improved performance was demonstrated in comparison with the conventional uniform annealing method.