LAUSR

Abstract As a promising material for optoelectronic devices, cesium lead halide perovskite nanocrystals have attracted wide attention recently. However, the fast anion exchange among CsPbX3 is a problem for applications (e.g., light emitting diode, LED) that require different colors. In this work, we report the large-scale synthesis of ultrathin cesium lead bromide (CsPbBr3) nanoplates (NPs) of tunable edge length and thickness via a simple one-pot colloidal approach. The thickness of NPs can be precisely tuned in a monolayer level by varying the reaction kinetics. The high-quality ultrathin NPs can be prepared in large scale of 0.25 L/batch. The ultrathin CsPbBr3 NPs emit blue light due to the strong quantum confinement effect, in contrast to the green emission of bulk CsPbBr3. For the first time, a blue LED device has been successfully fabricated by using ultrathin CsPbBr3 NPs as the active layer. The use of CsPbBr3 perovskite as the emitting layer for blue LED may promote the development of next-generation LEDs and displays.