锂离子注入对V2O5薄膜光吸收的影响

采用真空蒸发经热处理制备了Ｖ２Ｏ５薄膜，使用二电极恒流法从１Ｍ／ＬＬｉＣｌＯ４的ＰＣ电解质溶液向Ｖ２Ｏ５薄膜注入锂离子，形成ＬｉｘＶ２Ｏ５（０≤ｘ≤０．５４），测量了Ｖ２Ｏ５薄膜近垂直反射和透射光谱，计算了光吸收系数。Ｘ射线衍射分析表明薄膜为微晶结构。吸收系数与光子能量关系曲线中存在两个不同的变化区域，光子能量较高部分，（αｈν）１２与ｈν有线性关系；较低部分，吸收光谱存在一个尾巴。这两个区域的分界能量取决于电子和锂离子的注入量。研究结果表明Ｖ２Ｏ５薄膜阳极电致变色起源于吸收边缘的移动，而阴极电致变色则来源于小极化子的吸收

Effect of Lithium-Intercalation on Optical Absorption of Vanadium Pentoxide Thin Films

Vanadium pentoxide thin films were prepared by thermal evaporation of V2O5 powder followed by annealing posttreatment in air. Lithium was inserted electrochemically from an electrolyte so that Lix V2O5 (0≤x≤0.54) was obtained. The normal transmittance and reflectance spectra were measured and optical absorption coefficient was calculated. X-ray diffraction analysis has showed that the posttreated V2O5 thin films were microcrystal structure. The optical absorption spectra of all films have exhibited two distinct regions of behavior: a high-energy region in which (αhν)1/2 varied linearly with hν and a low-energy tail. The dividing energy of the two distinct regions depends on electron and Li ion intercalation. The present results have given that the anode electrochromism of V2O5 thin films is shift of absorption edge, and the cathode one is absorption of small polarons in V2O5.