Optimizing optoelectronic performances by controlling halide compositions of MAPb(ClxI1−x)3 single crystals

Abstract

This article aims at investigating the structures of iodide/chloride mixed-halide perovskites and correlating the I : Cl ratio with their optoelectronic performances. A series of 8 MAPb(Cl_xI_1−x)₃ (x = 0, 0.01, 0.04, 0.05, 0.06, 0.20, 0.99, and 1) single crystals were successfully grown. The crystals with different doping concentrations showed different optical absorption and PL emission. The band gaps were successfully tuned from 1.46 to 2.92 eV. Photodetectors were designed using the 8 crystals, among which the MAPb(Cl_0.2I_0.8)₃ single crystal exhibits the superior photocurrent to dark current ratio (I_light/I_dark ratio of 1547 when the incident light is ∼1609 μW cm⁻², 546 nm). This detailed investigation on Cl/I mixed halide lead methylammonium perovskites is important for optimizing device performances through composition tuning.