应变对Si掺杂A-TiO_(2)光学性质影响的第一性原理研究  

Effect of Strain on Optical Properties of Si Doped A-TiO_(2)Studied by the First-Principles

作　　者：张家琪 林雪玲[1] 田文虎 马文杰 张秀 马小伟 朱巧萍 郝睿 潘凤春[1] ZHANG Jiaqi;LIN Xueling;TIAN Wenhu;MA Wenjie;ZHANG Xiu;MA Xiaowei;ZHU Qiaoping;HAO Rui;PAN Fengchun(School of Physics,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学物理学院,银川750021

出　　处：《人工晶体学报》2025年第4期617-628,共12页Journal of Synthetic Crystals

基　　金：宁夏大学自治区级创新训练项目(S202410749052);大学物理卓越教学团队项目(ZYJXTD2023012);宁夏自然科学基金项目(2024AAC03012)。

摘　　要：运用基于密度泛函理论的第一性原理计算方法,研究了Si掺杂锐钛矿相TiO_(2)(A-TiO_(2))的电子结构和光学性质,以及应变对Si掺杂体系光学性质的调控。研究结果表明:Si掺杂形成的两种替位式缺陷中,Si_(Ti)缺陷不能有效改善TiO_(2)的光学性能,而Si_(O)缺陷的引入提高了掺杂体系对可见光区和红外光区光子的吸收,并且其光学吸收谱的吸收边发生了红移;光学性质的改变与掺杂体系的电子结构密切相关,Si_(Ti)缺陷对TiO_(2)电子结构的影响较小,而Si_(O)缺陷引入的杂质能级属于浅受主能级,该杂质能级的出现使掺杂体系的复介电函数在低能区有了很大的提升,促进了Si_(O)体系对低能区光子的吸收和光电转换效率,使Si_(O)体系的光催化特性有所增强。此外,光学性质还与Si_(O)的掺杂浓度有关,在108个原子的TiO_(2)超晶胞中均匀掺杂4个Si_(O),体系的光学性质最好,此时对应的掺杂浓度为3.7%。2%拉伸应变进一步增大了该体系对可见光区和红外光区光子的吸收,因此在2%拉伸应变下,Si_(O)均匀掺杂浓度为3.7%的体系具有更好的光电转换效率和光催化活性。The effects of strain on electronic structures and optical properties in Sidoped anatase TiO_(2)(A-TiO_(2))were studied by the first-principles calculation based on density functional theory.The results indicate that Si_(Ti) substitutions cannot improve the optical properties effectively,while Si_(O) 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 Sidoped TiO_(2)systems.Si_(Ti) substitutions cannot significantly alter the electronic structure in Si_(Ti) doped TiO_(2),which results in the optical properties of Si_(Ti) doped system are similar to those of the intrinsic TiO_(2)system.However,the impurity levels introduced by Si_(O) are shallow acceptor levels and locate in the bandgap of TiO_(2),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 Si_(O),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%Sidopant and 2%tensile strain in TiO_(2)may lead to better photoelectric conversion efficiency and photocatalytic activity.The study may provide a path for improving the optical properties of TiO_(2)through both doping Siand strain engineering.

关 键 词：TiO_(2) Si掺杂 应变 光学性能 电子结构 第一性原理计算 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学]