Tailored growth of high‐quality CsPbI 3 nanobelts

Nanobelts with a representative rectangular cross section have attracted much interest, owing to their unique applications for exploring novel and efficient optoelectronic nanodevices. In this work, we report the mass production of high‐quality single‐crystalline CsPbI 3 nanobelts by a one‐step template‐free process using a solvothermal method. The as‐prepared nanobelts are typically sized in 170–305 nm in width, 50–170 nm in height, and several microns in length, respectively. Accordingly, their width‐to‐height ratio of the cross section could be tailored from 1 to 6.35 by adjusting the amount of Cs 2 CO 3 within the raw materials, representing the formation of CsPbI 3 nanobelts in a tailored manner. The nanobelt growth was attributed mainly to a surfactant‐assisted, seed‐mediated anisotropic growth mechanism.