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Journal of Synthetic Crystals ›› 2025, Vol. 54 ›› Issue (4): 617-628.DOI: 10.16553/j.cnki.issn1000-985x.2024.0176

• Research Articles • Previous Articles     Next Articles

Effect of Strain on Optical Properties of Si Doped A-TiO2 Studied by the First-Principles

ZHANG Jiaqi, LIN Xueling, TIAN Wenhu, MA Wenjie, ZHANG Xiu, MA Xiaowei, ZHU Qiaoping, HAO Rui, PAN Fengchun   

  1. School of Physics, Ningxia University, Yinchuan 750021, China
  • Received:2024-08-13 Online:2025-04-15 Published:2025-04-28

Abstract: The effects of strain on electronic structures and optical properties in Si doped anatase TiO2 (A-TiO2) were studied by the first-principles calculation based on density functional theory. The results indicate that SiTi substitutions cannot improve the optical properties effectively, while SiO defects can upgrade the absorption amplitude for visible and infrared photons, and cause a redshift in the absorption edge of the optical absorption spectra obviously. The improved optical properties are closely related to electronic structures of Si doped TiO2 systems. SiTi substitutions cannot significantly alter the electronic structure in SiTi doped TiO2, which results in the optical properties of SiTi doped system are similar to those of the intrinsic TiO2 system. However, the impurity levels introduced by SiO are shallow acceptor levels and locate in the bandgap of TiO2, which can greatly improve the complex dielectric function in the low-energy region, promoting absorption and photoelectric conversion efficiency of low-energy photons, and therefore enhancing photocatalytic performance of the system. In addition, the optical properties are also related to doping concentration of SiO, which achieve the best with concentration of 3.7%. On the other hand, the tensile strain of 2% can further increase the absorption amplitude of visible and infrared photons for the system with a doping concentration of 3.7%. Therefore, 3.7% Si dopant and 2% tensile strain in TiO2may lead to better photoelectric conversion efficiency and photocatalytic activity. The study may provide a path for improving the optical properties of TiO2 through both doping Si and strain engineering.

Key words: TiO2, Si doping, strain, optical property, electronic structure, first-principles calculation

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