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 3+ -doped Cs 2 NaTbCl 6 using a solvothermal method to investigate its tunable photoelectric properties and low toxicity. Upon Sb 3+ ion doping, the photoluminescence yield (PLQY) of Cs 2 NaTbCl 6 significantly increased from ∼1.7 to ∼47%. The introduced Sb 3+ ions with ns 2 electronic configuration expanded the rare-earth element's absorption cross section, broke intrinsic forbidden transitions, and suppressed nonradiative recombination. Additionally, the codoping of Sb 3+ and Mn 2+ facilitated efficient energy transfer, resulting in highly efficient photoluminescence. The PLQY of 1%Sb 3+ ,3%Mn 2+ :Cs 2 NaTbCl 6 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.