单斜态Na0.2TiO2电子结构和光学性质的研究

采用基于密度泛函理论的平面波赝势方法，对Na0.2TiO2的能带结构、电子态密度和电荷密度进行了分析计算。结果表明，Na0.2TiO2属于一种间接带隙半导体，禁带宽度为2.81eV；其电子态密度主要由Ti的3d层电子和O的2p层电子的能态密度决定；该材料对紫外线有较强的宽频吸收，拓展了光谱响应范围，提高太阳能利用转化率和光催化效率；H-O键比Na-O键结合的更紧密，Na原子与O原子形成的是离子性较强而共价键较弱的混合键，Ti-O键的共价作用要强于Na-O键。因此，可以通过阳离子交换来调变钛酸钠的键特性及稳定性。

Study of electronic structure and optical properties of monoclinic Na0.2TiO2

The band gap, density of states,electron density of monoclinic Na0.2TiO2 were simulated by using the plane wave pseudo potentials （PWPP） based on the density functional theory（DFT）. Calculated results show that Na0.2TiO2 is an indirect semiconductor with the band gap of 2.81 eV. The density of states is mainly made up of Ti 3d and O2p. The material has strong broadband UV absorption,extends the range of spectral response and increases utilization rate of solar energy and photocatalytic efficiency. While the Na and O atoms is connected by a strong ionic and weak covalent mixed bond, the Ti-O bond is shorter and has more covlent component than Na-O bond. This work may provides a theoretical guid for the molecular design and applications of Na0.2TiO2 and related materials. Therefore ,the bond characteristics and stability of sodium titanate can be changed by cation-exchange.