With the addition of Na⁺ and Bi³⁺ to the lead-free double perovskite Cs₂AgInCl₆, high photoluminescence quantum yields (PLQYs) can be achieved, making Cs₂AgInCl₆ more promising; however, it is still difficult to achieve blue-light-excited narrowing emission. In this study, Cs_2−xK_xAg_0.6Na_0.4In_0.8Bi_0.2Cl_6−xBr_x was developed with K⁺ and Br⁻, realizing blue-light-excited narrowing red photoluminescence under cryogenic temperatures. The transitional non-localized donor energy level was formed by KBr addition, changing the exciton excitation and transition process. With the increase in the x value, Cs_2−xK_xAg_0.6Na_0.4In_0.8Bi_0.2Cl_6−xBr_x can be excited by blue light at 150 K and emit a narrowing red light. When 1 : 1 KBr was added, the full width at half maximum (FWHM) of Cs_2−xK_xAg_0.6Na_0.4In_0.8Bi_0.2Cl_6−xBr_x red light emission was further narrowed to only 73 nm, when excited by 467 nm blue light at 10 K. This study will stimulate further research on lead-free double perovskites in the field of display technologies.

中文翻译：

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具有低温效应的无铅双钙钛矿 Cs2−xKxAg0.6Na0.4In0.8Bi0.2Cl6−xBrx 中的蓝光激发变窄红色光致发光

通过在无铅双钙钛矿Cs ₂ AgInCl _{6 中}加入Na ⁺和Bi ³⁺，可以获得高光致发光量子产率（PLQYs），使Cs ₂ AgInCl ₆更有前景；然而，实现蓝光激发的窄发射仍然很困难。在本研究中，Cs _{2− x} K _x Ag _0.6 Na _0.4 In _0.8 Bi _0.2 Cl _{6− x} Br _x与 K ⁺和 Br ^{- 一起开发}，在低温下实现蓝光激发变窄的红色光致发光。过渡非定域供体能级是通过添加 KBr 形成的，改变了激子的激发和跃迁过程。随着x值的增加，Cs _{2- x} K _x Ag _0.6 Na _0.4 In _0.8 Bi _0.2 Cl _{6- x} Br _x可被150 K的蓝光激发并发出变窄的红光。当添加 1 : 1 KBr 时，Cs _{2− x} K _x Ag _0.6 Na _0.4 In _{0.8 的}半峰全宽 (FWHM)Bi _0.2 Cl _{6− x} Br _x红光发射在 10 K 时被 467 nm 蓝光激发时进一步缩小至仅 73 nm。该研究将刺激在显示技术领域对无铅双钙钛矿的进一步研究。