摘要
新型AgSnO_(2)材料是现在最合适代替AgCdO的电接触材料,但其使用过程中会在表面析出SnO_(2)晶体。而SnO_(2)的导电性极差,会影响电触头的使用。如何改善SnO_(2)的导电性能成了当今学者们研究的主要方向。采用基于密度泛函理论的第一性原理仿真构建了稀土元素Ce和Nd分别单掺杂和共掺杂SnO_(2)超晶胞,并分析计算了它们的能带图、态密度、电荷布局和电导率。分析结果表明单掺杂和共掺杂都能使SnO_(2)的带隙缩小,能带紧密,而共掺杂的效果要明显优于单掺杂。单掺杂时Ce原子的4f态和Nd原子的4f态分别在SnO_(2)的导带底引入新的杂质能级,导带底向着低能级方向移动。而Ce和Nd共掺杂时,在SnO_(2)的导带底和价带顶引入了更多的能级,进一步缩短了带隙;通过布局电荷分析得知Ce和Nd共掺杂SnO_(2)时体系的离子性要强于单掺杂;通过计算各个体系的电导率得到单掺杂和共掺杂都能使电导率增大,而共掺时电导率最大。
The new AgSnO_(2) material is the most suitable electrical contact material for replacing AgCdO material. But AgSnO_(2) electrical contact would precipitate SnO_(2) crystals on its surface during use. The conductivity of SnO_(2) is extremely poor,which affects the use of electrical contacts seriously. How to improve the electrical conductivity of SnO_(2) has become the main direction of scholars’ research.This research adopted the first principle based on density functional theory,and aimed to simulate and analyse the effects of co-doping Ce and Nd with SnO_(2) on energy band diagrams,state densities,charge distribution and electrical conductivity. The results showed that both single-doping and co-doping could reduce the band gap of SnO_(2),meanwhile tightening the energy bands. Moreover,the performance of co-doping samples was noticed significantly better than that of single-doping samples. The 4 f state of Nd atoms and Ce atoms during single doping introduced a new impurity level at the bottom of the SnO_(2) conduction band. The conduction band bottom moved toward the lower energy level. On the other hand,when Ce and Nd were co-doped,more energy levels were introduced to the conduction band bottom and the valence band top of SnO_(2),which further shortened the band gap. Furthermore,by the assistance of layout charge analysis,it was identified that the ionicity of the co-doped sample was stronger than that of the single-doped sample. Most importantly,both single doping and co-doping could contribute to the increase of electrical conductivity of SnO_(2) electrical conduction materials,and the effectiveness of co-doping was significantly higher than those of single doping.
作者
于双淼
王景芹
陈令
刘周
Yu Shuangmiao;Wang Jingqin;Chen Ling;Liu Zhou(State Key Laboratory of Reliability and Intelligence of Electrical Equipment,Hebei University of Technology,Tianjin 300130,China;Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province,Hebei University of Technology y Tianjin 300130,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2020年第11期1177-1183,共7页
Chinese Journal of Rare Metals
基金
国家自然科学基金项目(51777057)资助。
关键词
电接触材料
第一性原理
SnO_(2)
稀土元素共掺杂
电性能
electrical contact materials
first principles
SnO_(2)
rare earth element co-doping
electrical properties
作者简介
于双淼(1994-),男,河北唐山人,硕士研究生,研究方向:银氧化锡电触头材料,E-mdl:guangxinl02@163.com;通信作者:王景芹,教授,电话:13602176662,E-mail:jqwang@hebut.edu.cn。
