(a) Schematic illustration of the reaction system and process for the LARP technique. The starting materials in the precursor solution (top right) and the typical optical image of the colloidal MAPbBr₃ solution (bottom right) are illustrated.^[130] (b) The reversible anion exchange reaction of MAPbX₃ nanocrystals. (c) I–V curves of MAPbBr₃ film under 365 nm and 505 nm irradiation ( 60 mW · cm − 2 ) and dark conditions. The inset shows an SEM image of MAPbBr₃ film deposited on Au electrodes with a 2 μ m gap. (d) Photocurrents of MAPbBr_3−xCl_x and MAPbBr_3−xI_x as a function of x at different wavelength irradiations.^[136]