Enhanced energy transfer by Sb ion doping for efficient CsPbCl3:Mn2+ perovskite nanocrystals and light emitting diodes

Doping has been proved a promising strategy to enrich the optical properties and improve the photoelectric performance of perovskite materials. Mn2+ doped perovskite nanocrystals (NCs) have been paid considerable attention in light emitting diodes (LEDs), solar cells, etc. However, the low photoluminescence quantum yield (PLQY) of Mn2+ emission limits its practical applications. Herein, for the first time, we introduce Sb3+ into CsPbCl3:Mn2+ NCs to greatly improve the energy transfer efficiency from the NCs host to Mn2+, and then obtain a significant increase in the PLQY of Mn2+ emission. After the introduction of Sb3+, the PLQY of Mn2+ doped CsPbCl3 NCs increases from 5% to 52%, accompanied by an enhanced energy transfer efficiency from 39% to 67%. The temperature-dependent PL spectra and density functional theory (DFT) theoretical calculations reveal that the Sb3+ acts as an intermediate energy level between the CsPbCl3 NCs matrix and Mn2+ to offset the energy mismatch. LEDs based on CsPbCl3:Mn2+, Sb3+ NCs as the emissive layer are fabricated, and achieve an EQE improvement from 0.16% to 0.39%, and an increase in luminance from 19 cd m(-2) to 121 cd m(-2) after doping with Sb3+. Our work demonstrates an approach of energy regulation through ion doping, which is of great significance for fabricating efficient photoelectric materials and devices.