Perovskite Microdisk Microlasers Self‐Assembled from Solution

Single-crystalline square microdisks of CH3NH3PbBr3 are prepared by using a one-step solution self-assembly method. Single-mode lasing at 557 nm is achieved based on a built-in whispering gallery mode microresonator at room temperature. By partial replacement of Br with Cl, lasing wavelengths are continuously tuned from 525 to 557 nm.