【摘要】 运用第一性原理的LDA+U(U_Ti=5.8 eV)方法研究了Ti空位(V_Ti)和O空位（VO）对非掺杂锐钛矿相TiO₂的电子结构和光学吸收性质的影响.研究表明V_Ti可以有效提升TiO₂体系对可见光的响应,而VO则不能.在双V_Ti体系,由于杂质能级数目的增多可降低TiO₂体系的有效禁带宽度,进一步提升了TiO₂在可见光区的吸收强度.在V_Ti和VO共存的TiO₂体系,由VO引入的两个电子占据了费米能级处的杂质能级会使体系的价带顶上移,同时由VO引入的杂质能级位于禁带之间可以作为价电子由价带向导带之间跃迁的桥梁,因此此种结构对可见光的响应是最好的,有效的提高了TiO₂半导体的光电转换效率和光催化能力.更多还原

【Abstract】 The effects of Ti vacancy( V_Ti) and O vacancy（VO） on electronic structures and optical absorption properties in un-doped anatase TiO₂ have been investigated by the first-principles calculations of LDA + U method with U = 5. 8e V for Ti-3d. The calculation results indicated that the V_Tican enhance the response of TiO₂ system to visible light effectively,while VOhas not this effect. In the TiO₂ system with two V_Ti,the increase of impurity levels can reduce the effective band-gap,and therefore raise the absorption intensity in the visible light area. In the TiO₂ system with V_Tiand VO,the two electrons introduced by VOoccupy the impurity level near the Fermi level and therefore move up the valence band maximum. At the same time,the impurity level introduced by VOis located between the band-gap,which can benefit the valence electron transition from the valence band to the conduction band. Therefore,the system has the best response to visible light,which can raise photoelectric transformation efficiency and facilitate photocatalysis ability.更多还原