二维As2O3光催化性质理论研究

基于密度泛函理论的超软赝势第一性原理计算方法， 该文提出了一种新型P-3m1相二维As2O3， 并研究其结构稳定性， 电子结构和光催化性质. 计算结果显示， 二维As2O3具备较好的稳定性， 并具有1.04 eV的间接能隙. 基于形变势理论进一步计算了As2O3的载流子迁移率， 发现其电子和空穴的迁移率表现出明显的各向异性， 沿armchair和zigzag方向的电子/空穴迁移率分别为1259.91/115.41 cm2·V－1·s－1和1254.21/36.12 cm2·V－1·s－1， 这说明As2O3具备很低的电子－空穴复合率， 拥有较高的光催化活性. 对比标准氢电极的氧化还原势发现， 二维As2O3具备2.57 eV的氧化势能， 能够光催化水裂解出O3， O2 和H2O2等. 此外， 二维As2O3对可见光和紫外光表现出强烈的吸收效果， 吸收系数高达105 cm－1. 这表明二维As2O3在纳米电子器件和光催化领域有着潜在的应用前景.

Theoretical study on the photocatalytic properties of two-dimensional As2O3

Based on the first-principles calculation method of ultra-soft pseudopotential density functional theory， a novel two-dimensional As2O3 of P-3m1 phase is proposed，its stability， electronic structures and photocatalytic properties are further studied. The results show that As2O3 is indirect bandgap semiconductor with band-gap of 1.04 eV， and show high stability. Based on the deformation potential theory， we calculated the carrier mobility of monolayer As2O3， the results show that the mobility of electrons and holes are obviously anisotropic. The electron/hole mobility along Armchair/Zigzag directions are 1259.91/115.41 cm2 V－1·s－1 and 1254.21/36.12 cm2 V－1·s－1， respectively， indicating that monolayer As2O3 has a very low electron-hole recombination rate and with high photocatalytic activity. Compared with the REDOX potential of the standard hydrogen electrode， it is found that the oxidation potential of monolayer As2O3 is 2.57 eV， which can photocatalyze water cracking to produce O3， O2 and H2O2 et al. Furthermore， monolayer As2O3 shows strong absorption effect to visible and ultraviolet light， and the absorption coefficient is up to 105 cm－1. These properties indicate that monolayer As2O3 has a potential application prospect in nano electronic devices and photocatalysis.