Band-gap determination from diffuse reflectance measurements of semiconductor films, and application to photoelectrochemical water-splitting
Band-gap determination from diffuse reflectance measurements of semiconductor films, and application to photoelectrochemical water-splitting
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DOI：
10.1016/j.solmat.2007.05.005
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发表时间：
2007-09-06
影响因子：
6.9
通讯作者：
Murphy, A. B.
中科院分区：
文献类型：
--
作者：
Murphy, A. B.
二氧化钛半导体涂层的漫反射率的测量，如用于水分解，分析使用Kubelka-Munk辐射传输模型。发现直接从漫反射率确定涂层的带隙的广泛使用的实践是不准确的，因为漫反射率取决于诸如涂层的厚度、折射率和表面粗糙度的参数。然而，它示出的吸收系数可以从漫反射率使用反演方法导出;然后可以从吸收系数获得的带隙。最后，分析了Khan等人[Science 297（2002）2243-2245]提出的碳掺杂TiO 2的漫反射率;发现当带隙波长扩展到可见光区域时，它被高估了。此外，可见波长的光仅被非常弱地吸收，并且预期仅对水分解效率做出微小贡献。皇冠版权所有（c）2007年出版的爱思唯尔B. V.保留所有权利。
Measurements of the diffuse reflectance of TiO2 semiconductor coatings, such as are used for water splitting, are analysed using the Kubelka-Munk radiative transfer model. The widely used practice of determining the band gap of the coating directly from the diffuse reflectance is found to be inaccurate, since the diffuse reflectance depends on parameters such as the thickness, refractive index and surface roughness of the coating. However, it is shown that the absorption coefficient can be derived from the diffuse reflectance using an inversion method; the band gap can then be obtained from the absorption coefficient. Finally, the diffuse reflectance of carbon-doped TiO2 presented by Khan et al. [Science 297 (2002) 2243-2245] is analysed; it is found that while the band-gap wavelength is extended into the visible region, it is overestimated. Moreover, light at visible wavelengths is only very weakly absorbed, and is expected to make only a minor contribution to the water-splitting efficiency. Crown Copyright (c) 2007 Published by Elsevier B.V. All rights reserved.