Solution-Processed Perovskite Microdisk for Coherent Light Emission

High-quality semiconductor microdisks (MDs) are of crucial importance for realizing on-chip coherent light sources. However, the fabrication of all-inorganic semiconductor circular or circular-like microdisks (CMDs) with suitable size for optoelectronic applications is still complex and expensive. Herein, a facile ligand-free antisolvent-assisted growth method is used to synthesize high-quality Cs₄PbBr₆ MDs with tunable size and morphology, which is evolved from rhombohedral to octahedral, hexagonal-like, and circular-like MDs based on Cl-containing antisolvents. Significantly, this is the first time that large semiconductor CMDs are synthesized from solution self-assembled growth at room temperature. These Cs₄PbBr₆ MDs show high-efficient and stable green emission (522 nm), which should be attributed to the first-order excitonic emission from embedded CsPbBr₃ nanocrystals (NCs). The distribution of CsPbBr₃ NCs is verified by lattice fringe, crystal data refinement, and time-resolved photoluminescence analysis. These CsPbBr₃-in-Cs₄PbBr₆ CMDs are demonstrated to hold outstanding two-photon pumped coherent light emission ability with a remarkably low threshold (400 µJ cm⁻²). These findings suggest CsPbBr₃-in-Cs₄PbBr₆ MDs have excellent light emission capability and stability toward practical optoelectronic applications, and their tunable morphology and size indicate that solution method is feasible for the fabrication of semiconductor CMDs.