Origin of the Enhanced Visible Photocatalytic Activity in (N, C)-Codoped ZnS Studied from Density Functional Theory

摘要：

　　Density functional theory calculations are used to investigate the origin of the experimentally observed changes in visible photoactivity of hexa gonal wurtzite ZnS induced by (N,C) codoping.The accurate comparative analyses of geometric and electronic structures for the different doping models have been discussed.For the mono N-or C-doped ZnS systems,the substituted doping just induces a slight band gap narrowing (less than 0.2 eV),while the interstitial doping leads to more significant optical absorption red shift.However,the calculated energy indicates the formation of the interstitial doping is difficult with the lower impurity concentration.For the N+C-codoped systems,the dectron transition from the impurity states in the gap to the conduction band will induce a large red shift,suggesting the visible-light absorption.However,the impurity states are partially occupied character,which may act as recombination center and reduce the photoinduced current density.The calculated results of 2N+C-codoped ZnS indicate the N-C-N trimer structure was formed in the ZnS lattice,and the trimer doping induces a larger red shift of photoelectron transition and passivates the partially occupied states by the charge compensation effect in acceptor-donor-acceptor pair.Our work provides a solid basis for the rationalization of experimentally observed red shift of optical absorption in wurtzite ZnS as a consequence of(N,C) codoping and shows that 2N+C codoping will be a promising way for improving the visible-light activity of semiconductor photocatalysts.

作者: Honggang Sun Xian Zhao Liang Zhan Weiliu Fan

作者单位: State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics of CAS, Da State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China ;Department of C

会议类型: 国际会议

会议名称: The 6th International Conference of Molecular Simulations and Applied Informatics Technologies(第六届国际分子模拟与信息技术应用学术会议(ICMS&I))

会议地点: 南京

会议语种:英文

页码: 359-368

在线出版日期: 2012-05-13（万方平台首次上网日期，不代表论文的发表时间）