锐钛矿型TiO_2(101)面吸附CO_2分子的光学气敏传感机理  

Sensing mechanism of anatase TiO_2(101) surface adsorption of CO_2 molecules

作　　者：杨英[1] 冯庆[1] 

机构地区：[1]重庆师范大学物理与电子工程学院,重庆401331

出　　处：《红外与激光工程》2015年第7期2116-2121,共6页Infrared and Laser Engineering

基　　金：国家自然科学基金(61274128;1106129);重庆市自然科学基金(cstc2013jcyj A0731;cstc2014jcyj A50015);重庆市教委科学技术研究项目(KJ120614)

摘　　要：对金属氧化物光学气敏传感材料TiO2的探索与应用是当前研究的热点问题。采用基于密度泛函理论(DFT)中的平面波超软赝势方法,模拟计算CO2分子在锐钛矿型TiO2(101)表面的吸附行为,对吸附能,吸附距离,电子态密度以及光学性质进行分析。结果表明:CO2分子在含O空位表面的吸附效果优于无氧空位表面,且表面O空位的浓度越高,吸附效果越明显;分子平行于表面放置模型的吸附能为正值,吸附后的结构稳定,且以O端吸附为主,为此,分子平行于表面放置O端吸附于含两个O空位表面为最可能吸附模型;对电子态密度分析发现,当最佳模型吸附稳定后,含O空位表面为P型杂质,又有CO2分子中的2p电子掺入,在费米能级附近出现新峰值,改善了TiO2材料的光学性质,体现出较好的光学气敏传感特性。Exploration and application of the gas sensitive sensor material of metal oxide optics is a hot issue. The adsorption energy, adsorption distance, density of states and optical properties were studied from the plane wave ultra-soft pseudo-potential technology based on the density function theory（DFT）.The results through simulation calculation of CO2 adsorbed on the anatase TiO2（101） surface show that only containing oxygen vacancy surface can stably adsorb CO2molecules; the higher of oxygen vacancy concentration, the more obvious adsorption effect. The adsorption energy is positive value when CO2 molecules horizontal adsorption on surface, the best adsorption model is CO2 molecules horizontalO-terminal dsorption on surface with two oxygen vacancies. Compared with the density of states, a new peak appears nearby the fermi level because of surface with oxygen vacancies and 2p electrons of CO2 molecules doping in surface. The transition probability, optical gas sensitive features, absorption coefficient and reflectivity can be improved in the low-energy scope of visible light.

关 键 词：表面吸附 光学气敏传感材料 锐钛矿 密度泛函理论 

分 类 号：O469[理学—凝聚态物理] O482.3[理学—电子物理学]