The refinement of XRD patterns only provides the average structure parameters for the alloying materials because of the symmetric protection. Raman vibrational modes can append the detailed information about the bond length and structure. The refinements of XRD patterns for Bi alloying Cs₂AgInCl₆ revealed the strong structure distortion with the enlarged octahedron of In(Bi)Cl₆ and the contracted octahedron of AgCl₆ with the increasing Bi. Raman spectra supported the expanded octahedron of InCl₆ and the reduced octahedron of AgCl₆ but identified the anomalous shortening bond length of Bi–Cl with the increasing Bi. These distorting octahedrons break parity forbidden transition, modify Huang–Rhys factor, and result in the maximum values at 30% Bi alloying and the same variation trend for both photoluminescence and Huang–Rhys factor with the increasing Bi alloying.

中文翻译：

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双合金Cs ₂ AgInCl ₆晶体通过XRD，拉曼，黄-Rhys因子和光致发光的异常八面体畸变

由于对称保护，XRD图案的细化仅提供合金材料的平均结构参数。拉曼振动模式可以附加有关键长和结构的详细信息。Bi合金化Cs ₂ AgInCl ₆的XRD图谱的细化显示，随着In（Bi）Cl ₆的八面体的增大，BiCl的增加，AgCl ₆的收缩八面体的结构畸变很强。拉曼光谱支持InCl ₆的扩展八面体和AgCl ₆的还原八面体但随着Bi的增加，Bi-Cl的异常缩短了键长。这些扭曲的八面体打破了奇偶性的禁忌过渡，修改了Huang-Rhys因子，并导致Bi合金含量达到30％时的最大值，并且随着Bi合金含量的增加，光致发光和Huang-Rhys因子的变化趋势相同。