S与Hf/Ta/W掺杂锐钛矿相TiO_2电子结构和光学性质的第一性原理研究

First-principles Study on Electronic Structure and Optical Property of S and Hf/Ta/W Doped Anatase TiO_2

运用第一性原理密度泛函理论,计算了S单掺及S和过渡金属X(Hf、Ta、W)共掺锐钛矿相TiO_2后的电子结构和光学性质。计算结果表明,S单掺及S和X(Hf、Ta、W)共掺杂锐钛矿TiO_2后,带隙变窄,表明掺杂后的体系导电性能增强,其中Ta、W与S共掺后,费米能级穿过导带,表现出n型半导体特征;光学性质结果表明:掺杂后各体系的吸收光谱吸收带边均发生红移,S-Ta共掺和S-W共掺体系红移程度最大,并且在可见光区域出现吸收峰,S-W共掺体系的吸收峰最大,说明了该体系的光催化功能较强。各掺杂体系的反射率主峰均向低能方向移动,共掺移动幅度更大,且S-W共掺体系的反射系数在可见光区最大。各共掺体系的静态折射率依次增大,其中S-Hf共掺体系静态折射率在各体系中最小。

Using the first-principles density functional theory,electronic structure,and optical properties of X（ Hf,Ta,W） and S doped TiO2 systems were calculated. The results show that the band gap becomes narrower after S and X（ Hf、Ta、W） doped in anatase Ti O2,in which the conductivity of Ta-S and W-S co-doped anatase TiO2 are enhanced. With the Fermi level through the conduction band,the Ta-S and W-S co-doped anatase TiO2 systems are N-type semiconductor. The results of optical properties show that the red-shift takes place in the absorption spectra of all systems after doping,there is the maximum degree of red-shift in the S-Ta co-doped and S-W co-doped systems,the absorption peaks are in the visible light region,and the absorption peaks in the S-W co-doped system is the largest peak which indicates that the system has a strong photocatalysis. The main peaks of the reflectivity of each doping system move toward low energy,the co-doping movement is greater,and the reflection coefficient of theS-W co-doped system is the largest in the visible region. The static refractive index of each co-doped system increases sequentially,and the static refractive index of the S-Hf co-doped system is the smallest in each system.