Effect of Se Doping on the Electronic Band Structure and Optical Absorption Properties of Single Layer MoS2
Gang LI,Min-Qiang CHEN,Shi-Xiong ZHAO,Peng-Wei LI,Jie HU,Sheng-Bo SANG,Jing-Jing HOU*()
MicroNano System Research Center, Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education & College of Information Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
Based on the first principles method of density functional theory, the band structure and optical absorption properties of single-layered MoS2 doped with Se were calculated. Additionally, its effect on the properties of water splitting was analyzed. The calculations showed that the intrinsic MoS2 monolayer has a direct band gap structure with a value of 1.740 eV. The bottom edge of the conduction band was 0.43 eV above the reduction potential of H+/H2, while the top edge of the valence band was only 0.08 eV below the oxidation potential of O2/H2O. The results indicated that the intrinsic MoS2 monolayer has the potential for the photocatalytic decomposition of water when exposed to visible light. However, as the values of the oxidation and reduction processes were not balanced, the water splitting efficiency of a single-layer MoS2 photocatalyst would be low. When the MoS2 layer was doped with Se the band gap decreased to 1.727 eV, while the corresponding optical absorption spectrum was almost unchanged, and the formation energy of the system was relatively low. These results indicated that single-layered MoS2 should be thermally stabile following doping with Se. Significantly, the bottom edge of the conduction band decreased to 0.253 eV above reduction potential of H+/H2, while the top edge of the valence band increased to 0.244 eV below the oxidation potential of O2/H2O. Thus, the oxidation and reduction processes were balanced, and the water splitting efficiency of single-layered MoS2 should be greatly improved when exposed to visible light.
Received: 07 June 2016
Published: 20 September 2016
Fund: The project was supported by the National Natural Science Foundation of China(61674113，51622507，61471255);Natural Science Foundation ofShanxi Province, China(2014011019-1，20141001021-2，2016011040);Research Project Supported by Shanxi Scholarship Council, China(2013-036);Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province, China(251);TechnologyFoundation for Selected Overseas Chinese Scholar, Ministry of Personnel of China(240);and Scientific and Technologial InnovationPrograms of Higher Education Institutions in Shanxi Province, China(2016138)
Gang LI,Min-Qiang CHEN,Shi-Xiong ZHAO,Peng-Wei LI,Jie HU,Sheng-Bo SANG,Jing-Jing HOU. Effect of Se Doping on the Electronic Band Structure and Optical Absorption Properties of Single Layer MoS2. Acta Physico-Chimica Sinca, 2016, 32(12): 2905-2912.