单点缺陷氧化石墨烯电子结构与光学特性的第一性原理研究

First-principles Study on Electronic Structure and Optical Properties of Single Point Defect Graphene Oxide

本研究采用基于密度泛函理论的第一性原理方法,在局域密度近似和广义梯度近似下,研究了单点缺陷下不同结构氧化石墨烯的电子结构和光学特性。研究结果表明:文中四种构型的氧化石墨烯为力学稳定结构,其中包含不饱和氧原子的氧化石墨烯结构在水裂解及制氢中具有重要应用潜力。能带及分波态密度计算结果表明,包含不饱和氧原子的构型为间接带隙半导体,其余构型均为直接带隙半导体,且掺杂类型和带隙值随结构不同而改变。氧化石墨烯的光学吸收表现为各向异性,且在垂直于平面方向上的吸收边蓝移到近紫外可见光区。包含sp3杂化形式的结构光学吸收系数比包含sp2杂化的结构高,说明碳氧双键和悬挂键的存在对吸收光谱有重要影响。

In this study,the electronic structure and optical properties of graphene oxide in different structures with single point defect are studied under local density of states approximation and generalized gradient approximation by first-principles calculations based on the density functional theory.The results show that four models are mechanically stable,among which the oxide graphene containing unsaturated oxygen atoms shows an important application potential in water cracking and catalysis.The calculated band structures and partial-wave density of states show that the model containing unsaturated oxygen atoms exhibits indirect band gap,while other models exhibit direct band gap,and the doping type and band gap values vary with different models.The absorption spectrum of graphene oxide is anisotropic,and the absorption edge moves to the near-UV and visible region in the direction perpendicular to the plane.plane.The optical absorption coefficient containing sp3 hybrid is slightly higher than that containing sp2 hybrid,suggesting that the carbon-oxygen double bond and hanging bond have important influence on the absorption spectrum.