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

Abstract

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.