Lead-free double perovskite phosphors are promising alternatives to lead halide perovskites for wide uses in optoelectronic applications, but suffer from a low quantum efficiency. Here, we propose to enhance the quantum efficiency of orange-emitting Cs₂Ag_0.4Na_0.6InCl₆:Bi via a codoping strategy. The internal quantum efficiency of Cs₂Ag_0.4Na_0.6InCl₆:1% Bi phosphor was increased from 89.9% to the record 98.4 and 98.6% by codoping with 1% Ni and 1% Ce, respectively. High-level density functional theory calculations have revealed that the enhanced efficiency is ascribed to the formation of shallow trap states by codoping with Ce, while codoping with Mn can create delocalized deep traps that decrease the quantum efficiency. By applying the (Bi,Ce)-codoped sample together with a blue BaMgAl₁₀O₁₇:Eu²⁺ phosphor, a white light-emitting diode with an excellent color rendering index of 95.7 and a correlated color temperature of 4430 K has been demonstrated. The developed Cs₂Ag_0.4Na_0.6InCl₆:Bi,Ce phosphor shows a great potential as down-conversion luminescent material in solid-state lighting for general illumination.

中文翻译：

---

高效无铅（Bi，Ce）掺杂的Cs ₂ Ag _0.4 Na _0.6 InCl ₆双钙钛矿，用于白色发光二极管

无铅双钙钛矿磷光体是卤化钙钛矿铅的有前途的替代品，可广泛用于光电应用中，但量子效率低。在这里，我们建议通过共掺杂策略提高发射橙色的Cs ₂ Ag _0.4 Na _0.6 InCl ₆：Bi的量子效率。Cs ₂ Ag _0.4 Na _0.6 InCl ₆的内部量子效率通过分别掺杂1％Ni和1％Ce，Bi：1％磷粉从89.9％增加到创纪录的98.4和98.6％。高级密度泛函理论计算表明，提高效率归因于与Ce共掺杂形成浅陷阱态，而与Mn共掺杂会产生离域深陷阱，从而降低了量子效率。通过将掺有（Bi，Ce）的样品与蓝色BaMgAl ₁₀ O ₁₇：Eu ²⁺磷光体一起使用，已证明了显色指数为95.7且相关色温为4430 K的白色发光二极管。发达的Cs ₂ Ag _0.4 Na _0.6 InCl ₆：Bi，Ce荧光粉作为固态照明中的下转换发光材料，具有很大的潜力，可用于一般照明。