Single‐Mode Distributed Feedback Laser Operation in Solution‐Processed Halide Perovskite Alloy System

Abstract A single‐mode laser operation from a solution‐processed halide perovskite alloy system, CH(NH₂)₂Pb(I_1−xBr_x)₃ (0 ≤ x ≤ 1), is reported. Despite its simplicity, the solution process results in halide perovskite alloy films of smooth and uniform surface morphology that exhibits characteristics of bandgap engineering, where t he bandgap and thus emission wavelength can be tuned (from near‐infrared to green) by controlling the anion composition ratio x. A set of thin films of the halide perovskite alloy are coated on top of the fused quartz substrates with engraved surface gratings and are optically excited to induce distributed feedback lasing action. Laser devices operate in single modes over a wide range of wavelengths, depending on the composition ratio, up to room temperature for x = 0 and 1 and up to 200 K for alloys. This study demonstrates control of the polarization of the single‐mode laser output by carefully choosing the grating period. The achievement is an important milestone toward the advancement in the applicability of halide perovskite materials to optoelectronic devices.