E-beam writing micropatterns on MAPI films. (a) PL intensity mapping of “Westlake University”. The dose for sites A, B, and C is 8800, 4050, and 0 μC/cm2. (b) PL emission peak mapping of “Westlake University.” (c) Corresponding PL spectra of sites A, B, and C, respectively. Inset is an optical image of “Westlake University”.