第一性原理计算A、B位掺杂对NaNbO_3电子结构的影响  

Influences of A and B site dopings on the electronic band structures of NaNbO_3 from first-principle calculations

作　　者：蓝奔月[1] 史海峰[1,2] 

机构地区：[1]江南大学理学院,无锡214122 [2]南京大学环境材料与再生能源研究中心,南京210093

出　　处：《原子与分子物理学报》2014年第4期648-651,共4页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金项目(21203077)

摘　　要：钙钛矿结构的NaNbO3具有光催化分解水和降解有机物的性能,但其禁带宽度为3.40eV,因此仅具有紫外光响应.为了实现其可见光响应,本文通过密度泛函理论计算探讨了A位(Ag+)掺杂和B位(Sb5+、V5+)掺杂对NaNbO3的电子结构和光吸收性能的影响.结果表明,掺杂Ag+后,O 2p轨道和Ag 4d轨道杂化进而导致价带位置上移.掺杂Sb5+后,Nb 4d轨道和Sb 5s5p轨道杂化,导致导带位置下移.掺杂V5+后,Nb 4d轨道和V 3d轨道杂化,也导致导带位置下移.基于上述结果,提出了通过A、B位掺杂NaNbO3实现其光吸收红移的机制,本研究对通过掺杂调控NaNbO3光催化材料的光吸收方面有一定的指导意义.NaNbO3 is known as a perovskite oxide that exhibits photocatalytic activity for water splitting and the reduction of CO2.Unfortunately,it only absorbs ultraviolet light owing to its wide band gap （Eg～ 3.40 eV）.In order to shift its optical absorption from UV region to visible light region,the influ-ences of A site （Ag＋）doping and B site （Sb5＋,V5＋）doping on the electronic structures and optical ab-sorption properties of NaNbO3 have been calculated by first-principle calculations based on density func-tional theory （DFT）.As for Ag＋doping,the O 2p states are mixed with Ag 4d states so as to move the top of valence band upward.After Sb5＋ or V5＋ doping,the Nb 4d states are mixed with Sb 5s5p states or V 3 d states,which results in the downward shift of the bottom of conduction band.Based on the cal-culated results,the possible mechanisms for realizing the red shift of absorption edge are proposed, which would be significance of developing doped NaNbO3 photocatalytic materials under visible light.

关 键 词：NaNbO3 第一性原理 掺杂 能带结构 态密度 

分 类 号：O641[理学—物理化学]