Size-tunable CsPbBr3 perovskite ring arrays for lasing

Morphology engineering is a decisive factor for the optoelectronic properties of nanocrystals. Differing from morphologies with a solid interior, ring-like structures have a unique internal space which is not only available for loading chemicals, but also useful for controlling the field distribution. Herein, the perovskite array family welcomes a new member - CsPbBr3 ring arrays. This work solves several fundamental problems for fabricating CsPbBr3 ring arrays: (i) developing a simple method using 2D colloidal crystal templates to achieve ring arrays of CsPbBr3, (ii) finding two ways, say changing the template size or annealing of the template, to accurately tune the ring size of the array in a wide range from 2.6 mu m to 16.9 mu m, and (iii) investigating the dynamics of perovskite rings, which indicates a shrinking process towards the template spheres before the crystallization of the perovskites. Finally, the application of CsPbBr3 perovskite ring arrays to the field of lasers is shown.