B和氧空位VO掺杂锐钛矿相TiO2的结构特征

Characteristics of crystal structure of B and oxygen vacancies V_O doped anatase TiO_2

探讨非金属离子B和氧空位单掺杂和共掺杂TiO_2晶体对体系结构特征的影响。采用密度泛函理论框架下的第一性原理方法,研究了氧空位V_O和B离子掺杂锐钛矿相TiO_2体系的几何结构、形成能等问题。结果表明,无论是单掺杂还是共掺杂的形成都会使晶胞体积增加和晶体稳定性下降,而V_O/B共掺杂体系的晶胞畸变小于相应的B离子单掺杂情况,说明共掺杂体系的稳定性高于单掺杂体系。几何结构和形成能计算都表明,B原子更倾向于进入晶胞的晶格间隙之中,形成的晶隙掺杂Bin具有最高的热力学稳定性,并且,在含有V_O缺陷的TiO_2晶体基础上进行B原子掺杂比在完美TiO_2晶体基础上进行B掺杂的形成能更低、也就是这时的掺杂更容易。

The geometric structure and the formation energy of the VO and B atoms doped anatase TiO2 system were described by the first principles method based on the density functional theory.The results show that all kinds of defects will increase the unit cell volume and decrease the stability of the crystal.The distortion of unit cell of VO/B co-doped system is less than that of the corresponding B-doping,which shows that the stability of the co-doped system is higher than that of the single doping system.Geometry and energy calculations show that B atoms are more inclined to enter the hole of the matrix.