Cs_3Cu_2I_5晶体薄膜吸收谱的研究

The Absorption Spectra of Crystal Thin Film Cs 3Cu 2I 5

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 we measured the absorption spectra of crystal thin film Cs 3Cu 2I 5 at room and liquid nitrogen temperatures,respectively,and calculated the excitonic coefficient of the material.The excitonic coupling energy ΔE (1) ex =(0 53±0 07) eV,excitonic radius a ex =0 326 nm , and forbidden zone width E g=(5 00±0 07) eV .The spectral analysis shows that the electron and exciton excitations of the Cs 3Cu 2I 5 localize in the CuI subcrystal lattice,and reveals the law that governs the variance of the first excitonic peak position of the serial  Cs x Cu 1-x I  compounds with their mol components at low temperature.