高氧空位浓度对锐钛矿TiO_2莫特相变和光谱红移及电子寿命影响的第一性原理研究

First-principles research on the effect of high oxygen vacancy concentration in anatase TiO_2 on Mott phase transition,absorption spectrum Einstein shift and life-time of electrons

基于密度泛函理论的第一性原理研究,通过对锐钛矿TiO2高氧空位浓度、态密度图及吸收光谱图的分析,发现锐钛矿TiO2高氧空位浓度的条件下,高氧空位浓度对禁带变窄、吸收光谱红移和电子寿命都有很大的影响,从理论上进一步解释了高氧空位浓度对禁带变窄的原因.同时,锐钛矿半导体在高氧空位浓度时发生莫特相变和锐钛矿氧空位在等离子体中吸收光谱红移实验进行比较,发现锐钛矿TiO2应适量控制高氧空位浓度对吸收光谱红移好于前者.适量控制高氧空位浓度的锐钛矿TiO2对制备高氧空位浓度的可见光光催化剂提供了可靠的数据.

Based on the study of density function using first-principles theory, by studying the concentration of oxygen vacancies, the DOS and the absorption spectrum of anatase, we discovered that the high concentration of oxygen vacancies has great influence on the forbidden band gap, absorption spectrum Einstein shift and life-time of electrons, and explained the reason why the concentration of oxygen vacancy makes the forbidden band gap to narrow. At the same time, the anatase semiconductor has Mott transition when there is a high concentration of oxygen vacancies. The conclusion that suitably controlling the concentration of oxygen vacancy leads to Einstein shift is deduced by comparing the Einstein shift experiment of oxygen vacancies in anatase with that in the plasma. It offered credible data for preparation visible light activator suitably by controlling the concentration of oxygen vacancies in anatase.