Spin-Coated CH₃NH₃PbBr₃ Film Consisting of Micron-Scale Single Crystals Assisted with a Benzophenone Crystallizing Agent and Its Application in Perovskite Light-Emitting Diodes.

Owing to the superior properties of optical and electronic properties, perovskite single crystals have been in high demand recently. However, the growth of large-sized single crystals requires several processing steps and a long growth time, which engenders great difficulties in device integration. Herein, benzophenone (BP) was firstly introduced as a crystallizing agent to facilitate the construction of a high-quality CH₃NH₃PbBr₃ (MAPbBr₃) film consisting of micron-scale single crystals in a one-step spin-coating method. We studied the influence of the BP concentration upon the size and shape of the micron-scale single crystals. Moreover, due to the enhanced morphology of the MAPbBr₃ film with low-defect micron-scale single crystals, perovskite light-emitting diodes (PeLEDs) have been demonstrated with a maximum luminance of 1057.6 cd/m² and a turn-on voltage as low as 2.25 V. This approach not only proposes a concise and highly repeatable method for the formation of micron-scale perovskite single crystals, but also paves a way for the realization of efficient PeLEDs.