第一性原理研究In,Cr,Sb掺杂BiOIO_(3)的电子结构和光学性质

First principles study of the electronic structure and optical properties of In,Cr,Sb doped BiOIO_(3)

基于第一性原理研究In,Cr,Sb掺杂BiOIO_(3)的电子结构和光学性质的理论机制。BiOIO_(3)与In,Cr,Sb掺杂BiOIO_(3)四种结构体系的带隙值分别为1.910,1.837,1.777和1.603eV,与BiOIO_(3)本征带隙相比较,掺杂In,Cr,Sb元素后跃迁方式都由间接带隙变为直接带隙,这一变化表明掺杂后减少了跃迁需要的能量。且Cr掺杂体系表现出n型半导体特性,表明引入Cr加快了电子的迁移速率,使Cr掺杂BiOIO_(3)具有更高的导电性能。在对光学性质的研究中,发现掺杂元素Cr后BiOIO_(3)对紫外光、红外光区域的吸收能力都大幅度提升,并提高了可见光光催化活性。掺杂In,Cr,Sb后BiOIO_(3)晶体在1064nm处的双折射率分别为0.227,0.141和0.247,In和Sb掺杂增大了双折射率,而掺杂Cr元素降低了双折射率。

On the basis of first principles,the theoretical mechanism of the electronic structure and optical properties of In,Cr,Sb doped BiOIO_(3)were investigated.The band gap of BiOIO_(3)and In,Cr,Sb-doped BiOIO_(3)is 1.910,1.837,1.777 and 1.603 eV,respectively.Comparing with BiOIO_(3),the doping of In,Cr,and Sb elements changes the mode of jumping from indirect bandgap to direct bandgap.This difference implies that the energy required for the transition is lowered after doping.Meanwhile,the Cr-doped system exhibits n-type semiconductor properties,indicating that the introduction of Cr accelerates the electron migration rate,resulting in higher electrical conductivity of Cr-doped BiOIO_(3).It is discovered that the absorption capacity of BiOIO_(3)doped with Cr elements in ultraviolet light and infrared light region can be greatly improved,as is the photocatalytic activity of visible light.The birefringence at 1064 nm of BiOIO_(3)crystal doped with In,Cr,and Sb is 0.227,0.141,and 0.247,respectively.Doping with In and Sb enhances the birefringence while doping with Cr decreases the birefringence.