Electronic And Optical Properties Analysis On Doped Anatase TiO₂

Anatase TiO2which has broad application prospects in environmental purification, solarcells and photoelectric catalysis because of its excellent properties, such as photocatalysis,super hydrophilic, antibacterial, is an excellent semiconductor photocatalyst. Duo to the largeband gap of anatase TiO2, which will lead to the low utilization rate of sun light, limits itsapplication. Research shows that the doping is an effective method. In this paper, theelectronic structures and optical properties of Bi, P, Hg for single doped and Bi-N, W-S, Fe-S,Mn-S for codoped anatase TiO2were calculated using the first-principles plane-waveultra-soft pseudo-potential method based on the density functional theory.It was found that the impurity levels in the band gap was introduced into Bi doped TiO2,the band gap increased a little, and the doping induce significantly enhancement in visiblelight. To P doped TiO2, the isolated impurity levels appeared in the band gap, and the width offorbidden band, absorption enhancement in the visible region and the blue shift degree ofabsorption spectral edges increase with P doping concentration increasing. The band gap ofthe Hg-doped anatase TiO2without O vacancy is narrowed, while that of the Hg-dopedanatase TiO2with O vacancy is widened, and some impurity energy leVels induced. And theabsorption edges of the Hg-doped anatase TiO2with and without O vacancy show blue shiftand red shift, respectively.It was found that the band gap of Bi-N codoped anataseTiO2increased and induced someimpurity energy levels. The absorption show enhancement in the visible region; To W-Scodoped TiO2, the impurity energy levels were introduced and the width of band gapincreased which result in the blue shift of the absorption spectra. The band gap of the Fe-Scodoped anatase TiO2was narrowed and impurity energy levels were induced into forbiddenband. The absorption edges show redshifts and absorption enhancement in the visible region.The calculated results showed that the band gap of Mn-S codoped TiO2was increased, andtwo impurity bands appeared in the forbidden band. The absorption show enhancement inthe visible region.