Significant Enhancement in Visible Light Absorption of TiO2 Nanotube Arrays by Surface Band Gap Tuning
Significant Enhancement in Visible Light Absorption of TiO2 Nanotube Arrays by Surface Band Gap Tuning
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DOI：
10.1021/jp405207e
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发表时间：
2013-08
影响因子：
3.7
通讯作者：
S. Kurian;H. Seo;H. Jeon
中科院分区：
文献类型：
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作者：
S. Kurian;H. Seo;H. Jeon
宽带隙半导体TiO2的带隙调谐由于其在太阳能电池中的多用途特性而具有重要意义。TiO2的可见光活性可以作为光吸收材料，提高第三代太阳能电池的效率。在这项研究中，我们展示了通过阳极氧化和短期快速退火工艺修饰TiO2纳米管阵列（TNTA）的表面结构和带隙调谐。该TNTA显示紫外和整个可见光范围（400-700 nm，增加350%）的吸收。有效带隙为1.7 eV。通过详细的分析表明，在整个可见范围内，可见光吸收的显著增强是由于表面上的取代碳原子和间隙碳原子在表面上引入了结构紊乱和局域态。基于光电发射光谱的结果，可能带隙模型显示了表面的带弯曲。T…
Band gap tuning of the wide band gap semiconductor, TiO2, has great importance due to its versatile properties in solar cell applications. Visible light activity of TiO2 can enhance the efficiency of the third-generation solar cells by acting itself as light absorbing material. In this study, we demonstrate a surface structure modification and band gap tuning of TiO2 nanotube arrays (TNTA) by anodization accompanied by a short-term, quick annealing process. This TNTA shows absorption both in the UV and entire visible range (400–700 nm, an increase by 350%). The effective band gap is found to be 1.7 eV. Through a detailed analysis we show that the significantly enhanced visible light absorption in the entire visible range is due to the substitutional and interstitial carbon atoms on the surface which introduces a structural disorder and localized states at the surface compared to the bulk. Based on the results from photoemission spectra, the probable band gap modeling shows a band bending at the surface. T...