Random lasing in organo-lead halide perovskite microcrystal networks

We report optically pumped random lasing in planar methylammonium lead iodide perovskite microcrystal networks that form spontaneously from spin coating. Low thresholds (<200 μJ/cm²) and narrow linewidths (Δλ < 0.5 nm) reflect lasing from closed quasi-modes that result from ballistic waveguiding in linear network segments linked by scattering at the junctions. Spatio-spectral imaging indicates that these quasi-modes extend over lateral length scales >100 μm and spatially overlap with one another, resulting in chaotic pulse-to-pulse intensity fluctuations due to gain competition. These results demonstrate this class of hybrid organic-inorganic perovskite as a platform to study random lasing with well-defined, low-level disorder, and support the potential of these materials for use in semiconductor laser applications.