物理化学学报 >> 2016, Vol. 32 >> Issue (12): 2905-2912.doi: 10.3866/PKU.WHXB201609201

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Se掺杂对单层MoS2电子能带结构和光吸收性质的影响

李刚,陈敏强,赵世雄,李朋伟,胡杰,桑胜波,侯静静*()   

  • 收稿日期:2016-06-07 发布日期:2016-11-30
  • 通讯作者: 侯静静 E-mail:sangshengbo@tyut.edu.cn
  • 基金资助:
    国家自然科学基金(61674113,51622507,61471255);山西省自然科学基金(2014011019-1,20141001021-2,2016011040);山西省回国留学人员科研项目(2013-036);山西省人社厅留学人员择优资助项目([2013]251);人社部留学人员择优资助项目([2014]240);和山西省高校科技创新研究项目(2016138)

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*()   

  • Received:2016-06-07 Published:2016-11-30
  • Contact: Jing-Jing HOU E-mail:sangshengbo@tyut.edu.cn
  • Supported by:
    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([2013]251);TechnologyFoundation for Selected Overseas Chinese Scholar, Ministry of Personnel of China([2014]240);and Scientific and Technologial InnovationPrograms of Higher Education Institutions in Shanxi Province, China(2016138)

摘要:

基于密度泛函理论的第一性原理方法,计算了Se掺杂单层MoS2能带结构和光吸特性,并分析了对其光解水性质的影响。结果表明:本征单层MoS2为直接带隙结构,禁带宽度为1.740 eV,导带底电位在H+/H2还原势之上0.430 eV,价带顶电位在O2/H2O的氧化势之下0.080 eV,具有可见光催化分解水的能力,但氧化和还原能力不均衡,导致单层MoS2作为光催化剂分解水的效率不高。通过Se掺杂计算发现,单层MoS2的禁带宽度变为1.727 eV,相应的光吸收谱变化幅度几乎不变,且体系的形成能较低,表明其热力学稳定性良好。然而,导带底电位调整到H+/H2还原势之上0.253 eV,价带顶电位处于O2/H2O的氧化势之下0.244 eV,平衡了氧化与还原能力,单层MoS2可见光催化分解水的效率得到提高。

关键词: 单层MoS2, 掺杂, 光解水, 第一性原理

Abstract:

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.

Key words: Single layer MoS2, Doping, Photocatalytic splitting of water, First principles

MSC2000: 

  • O641