Neodymium Chloride-Doped Perovskite Nanocrystals for Efficient Blue Light-Emitting Devices.

Metal halides doping of perovskite nanocrystals (NCs) has been shown to precisely control nonradiative pathways and to improve photoluminescence quantum yield (PLQY). Here, we report a trivalent lanthanide halide neodymium (III) chloride (NdCl)-doped perovskite NCs prepared with a post-synthetic room temperature treatment for efficient blue light-emitting devices (LEDs). The Nd 3d and Cl 2p core peaks were observed in the NdCl-doped NCs, which allowed for simultaneous doping of Nd and Cl into the pristine CsPbBr NCs. The NdCl-doped NCs exhibited blue emission at a peak wavelength of 478 nm with a high PLQY of 97% in solution. We found that the Nd cation incorporated into the NCs more effectively suppressed nonradiative recombination compared with common halide anion exchange from temperature dependence of optical properties. Blue LEDs based on NdCl-doped NCs had an external quantum efficiency of 2.7%, which represents a considerable performance improvement compared with LEDs based on organic chloride salt-doped NCs.