本文测定了Ｃｓ３Ｃｕ２ Ｉ５ 晶体薄膜在室温及液氮温度下的吸收谱，并依此计算出该材料的激子参数，即激子束缚能ΔＥ（１）ｅｘ ＝ （０．５３±０．０７）ｅＶ，激子半径ａｅｘ ＝ ０．３２６ ｎｍ ，禁带宽度Ｅｇ ＝ （５．００±０．０７）ｅＶ。在谱分析的基础上，论证了Ｃｓ３Ｃｕ２Ｉ５ 的电子和激子激发定域在该晶体的ＣｕＩ亚晶格之中，同时，揭示了在低温下Ｃｓｘ Ｃｕ１－ ｘ Ｉ系列化合物的第一激子峰位置随其摩尔组分变化的规律。 In this paper, the absorption spectra of Cs3Cu2 I5 thin films at room temperature and liquid nitrogen temperature were measured and the exciton parameters of the material were calculated, ie, the exciton binding energy ΔE (1) ex = (0.53 ± 0.07) eV, exciton radius aex = 0.326 nm, band gap Eg = (5.00 ± 0.07) eV. Based on the spectral analysis, it is demonstrated that the electron and exciton excitation of Cs3Cu2I5 are localized in the CuI sublattice of the crystal, and the first exciton peak position of the CsxCu1-xI series compound at low temperature With the changes in the molar composition of the law.