Effective Energy Transfer Boosts Emission of Rare-Earth Double Perovskites: The Bridge Role of Sb(III) Doping.

Halide perovskites have attracted considerable interest due to their excellent photoelectric properties. In this study, we synthesized Sb-doped CsNaTbCl using a solvothermal method to investigate its tunable photoelectric properties and low toxicity. Upon Sb ion doping, the photoluminescence yield (PLQY) of CsNaTbCl significantly increased from ∼1.7 to ∼47%. The introduced Sb ions with ns electronic configuration expanded the rare-earth element's absorption cross section, broke intrinsic forbidden transitions, and suppressed nonradiative recombination. Additionally, the codoping of Sb and Mn facilitated efficient energy transfer, resulting in highly efficient photoluminescence. The PLQY of 1%Sb,3%Mn:CsNaTbCl reached a remarkable 85.8%, marking the highest reported value for rare-earth double perovskites in the visible light region. This study highlights the vital role of Sb(III) doping as a bridging agent to enhance the emission in rare-earth double perovskites.