K+掺杂双钙钛矿Cs2AgInCl6的发光性质

采用固相球磨法制备了K⁺掺杂双钙钛矿Cs₂AgInCl₆纳米材料，该方法无需配体辅助，绿色环保。通过X射线衍射和拉曼光谱对晶体结构进行研究，通过激发光谱、发射光谱和时间分辨光谱对其发光性能进行研究。结果表明，Cs₂AgInCl₆为立方晶体，属于Fm3m空间群，由于宇称禁戒跃迁，其荧光量子产率(PLQY)低，小于0.1%。低于60%的K⁺掺杂主要取代Ag⁺的位置，引起Cs₂AgInCl₆的晶格膨胀，消除了晶格结构的反演对称性，打破了宇称禁戒跃迁，掺杂后Cs₂AgInCl₆的光致发光强度显著增强。K⁺的最佳掺杂比例为40%，Cs₂Ag_0.6K_0.4InCl₆材料发射中心波长为640 nm，半高宽为180 nm，平均荧光寿命达到29.2 ns，PLQY达到10.5%。当K⁺掺杂比例超过60%，K⁺开始取代Cs⁺的位置，产物发生相变，出现立方相的Cs_2-xK_1+x-yAg_yInCl₆和单斜相的Cs_2-xK_1+xInCl₆产物，这些产物由于强电子-声子耦合，非辐射复合占据主导地位。

Luminescence properties of K+ doped double perovskite Cs2AgInCl6

K⁺ doped double perovskite Cs₂AgInCl₆ nanomaterial was prepared by solid phase ball milling method, which is environmentally friendly without ligands. The crystal structure was studied by X-ray diffraction and Raman spectrum, and the luminescence properties were studied by excitation spectrum, emission spectrum, and time-resolved spectrum. The results show that the Cs₂AgInCl₆ is a cubic crystal, which belongs to Fm3m space group. Due to parity-forbidden transition, the photoluminescence quantum yield (PLQY) is low, less than 0.1%. When K⁺ doping is less than 60%, it mainly replaces Ag⁺, which causes lattice expansion of Cs₂AgInCl₆, eliminates inversion symmetry of lattice structure, breaks parity forbidden transition, and enhances photoluminescence intensity of Cs₂AgInCl₆. The optimal doping ratio was 40%, the center wavelength of Cs₂Ag_0.6K_0.4InCl₆ was 640 nm, the half-height width was 180 nm, the average fluorescence lifetime was 29.2 ns and the PLQY reached 10.5%. When the doping ratio of K⁺ exceeds 60%, K⁺ begins to replace the position of Cs⁺, which results in the presence of cubic phase Cs_2-xK_1+x-yAg_yInCl₆ and monoclinic phase Cs_2-xK_1+xInCl₆. These products are dominated by non-radiative recombination due to strong electron-phonon coupling.