Directional Laser from Solution‐Grown Grating‐Patterned Perovskite Single‐Crystal Microdisks.

Solution‐processed, high‐gain, and wavelength‐tunable perovskite single‐crystal microdisk (PVKsc‐MD) lasers have emerged as prospective coherent light sources in advanced nanophotonic designs. However, the inevitable multi‐directional emission from a highly symmetrical cavity leads to low light collection efficiency which greatly hinders its application in integrated optical circuits. Here, we report on surface‐patterned MAPbBr3 PVKsc‐MDs synthesized by a cost‐efficient bottom‐up solution process employing spin‐coating and confined‐growth nanoimprinting. The patterned microdisks have high crystal quality with regular shape and sharp edges and nano‐grating structure on the upper surface. This straightforward process yields surface‐patterned PVKsc‐MD lasers with a low lasing threshold and high quality (Q) factor. In addition, the grating structure patterned on the PVKsc‐MDs reduces the original symmetry of the laser cavity, which improves the emission directionality four times. [ABSTRACT FROM AUTHOR]