Fig8 Spectral transmittance of the WO3/ITO/glass sample after successive lithiations steps.

Spectral transmittance of the WO3/ITO/glass sample after successive lithiations steps; the caption indicates the lithium content in the film. For comparison, the transmittance of the ITO substrate is added.
The optical properties of the samples are studied by spectrophotometry in the range of 350-2100 nm. The light source is composed of quartz tungsten halogen lamps and UV fluorescence lamps in an aluminum enclosure with a diffusing front glass. Stabilized DC power supplies are used to ensure a high temporal stability of the intensity of radiation. A diaphragm ensures that the light is illuminating the sample only. The collimator contains a quartz lens with an aperture of 28 mm and a focal length of 76 mm to focus the incoming radiation on the entrance of an optical fiber. This y-shaped optical fiber is connected to two diode array spectrometers UV-Vis and NIR (MCS 601 and MCS 611 from Zeiss) [22][23]. The wavelength accuracy of the spectrophotometer is 0.5 nm for λ<500 nm and 1 nm for λ>500 nm and the wavelength reproducibility is 0.1 nm.

经连续锂化步骤处理后的三氧化钨（WO₃）/氧化铟锡（ITO）/玻璃基底样品的光谱透过率；图注标注了薄膜中的锂含量。为便于对比，同时添加了ITO基底的透过率数据。
本研究采用分光光度法在350~2100 nm波段范围内对样品的光学特性进行表征。光源采用封装于铝制外壳内的石英钨卤素灯与紫外荧光灯，外壳前端配备漫射玻璃。系统配备稳压直流电源，以保障辐射强度的高时间稳定性。光阑仅允许光线照射至样品表面。准直单元搭载孔径28 mm、焦距76 mm的石英透镜，用于将入射辐射聚焦至光纤输入端。该Y型光纤分别连接两台二极管阵列分光光度计：紫外-可见光波段（UV-Vis）与近红外波段（NIR）的MCS 601和MCS 611（产自蔡司（Zeiss））[22][23]。该分光光度计的波长准确度为：波长λ<500 nm时为0.5 nm，λ>500 nm时为1 nm；波长重复性为0.1 nm。