摘要
基于密度泛函理论第一性原理研究了C、Co单掺杂以及Co/C共掺杂金红石相TiO2的电子结构和光学性质,并探究了Co/C共掺杂时C原子替换不同位置O的两种原子位形（C-1和C-2）对TiO2结构和性能的影响。结果表明：单掺Co和单掺C均会改变金红矿相TiO2的能带结构和电子态密度;掺杂Co能有效减小TiO2的禁带宽度。Co/C共掺杂的2种位形（Co/C-1、Co/C-2）的光谱吸收均优于Co、C单掺杂;当掺杂Co与C的位置互为次近邻关系（即位形Co/C-2）时,得到的带隙最小,其带隙宽度为1.740 e V。Co/C-2共掺杂带隙中存在4条杂质能级,其中2条来自于Co-3d态,另外2条来自于C-2p态;共掺后其带隙减小是C-2p态形成的杂质能级向价带移动的结果。Co/C-2共掺杂体系具有红移范围最广、吸收强度最大的光谱响应,增强了金红石相Ti O2的光吸收性能。
The electronic structures and optical properties of Co-,C-doped rutile TiO2 and two possible kinds of Co/C-co-doped rutile TiO2 were investigated by the first-principle calculation method based on the density functional theory.The effect of C-substituted O-site（i.e.,C-1 and C-2）on the electronic structures and optical properties of Co/C-codoped rutile TiO2 was also investigated.The results show that doping Co and doping C both can change the band structures and electronic density of states of rutile TiO2,in which doping Co can effectively reduce the band gap of TiO2.The spectral absorption of the two kinds of Co/C-co-doped systems is better than that of Co-doped and C-doped rutile TiO2.The Co/C-2 co-doped rutile TiO2 with a width of band gap 1.740 e V is minimum in the above systems,there are four impurity levels in its band gap.Two of which are from the Co-3d state and the other two impurity levels originate from the C-2p state,and the decrease of the width of band gap is since the impurity levels that come from C-2p state move into the valence band.The absorption spectrum shows that Co/C-2 co-doped rutile TiO2 has the broadest range of red shift and the optimum photosensitivity.This may be due to the impurity levels that cause the additional electron transition and enhance the photosensitivity and the photocatalytic performance of rutile TiO2.
作者
李鑫
冯宥霖
谢泉
LI Xin1, FENG Youlin2, XIE Quan1(1. College of Big Date and Information Engineering, Guizhou University, Guiyang 550025, China; 2. College of Architecture and Urban Planning, Guizhou University, Guiyang 550025, Chin)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2018年第7期946-951,共6页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金项目(61264004)
贵州省高层次创新人才培养项目([2015]4015)
关键词
光学性质
第一性原理
金红石相二氧化钛
电子结构
共掺杂
optical properties
first-principles
rutile titanium dioxide crystal
electronic structures
co-doped
