College of Chemistry, Key Laboratory of Green Chemistry and Technology in Ministry of Education, Sichuan University, Chengdu 610064 (P. R. China).
Chemphyschem. 2014 Jan 13;15(1):157-64. doi: 10.1002/cphc.201300768. Epub 2013 Nov 28.
A comprehensive first-principles theoretical study of the electronic properties and half-metallic nature of zigzag edge-oxidized graphene quantum dots (GQDs) is carried out by using density functional theory (DFT) with the screened exchange hybrid functional of Heyd, Scuseria and Ernzerhof (HSE06). The oxidation schemes include -OH, -COOH and -COO groups. We identify oxidized GQDs whose opposite spins are localized at the two zigzag edges in an antiferromagnetic-type configuration, showing a spin-polarized ground state. Oxidized GQDs are more stable than the corresponding fully hydrogenated GQDs. The partially hydroxylated and carboxylated GQDs with the same size exhibit half-metallic state under almost the same electric-field intensity whereas fully oxidized GQDs behave as spin-selective semiconductors. The electric-field intensity inducing the half metal increases with the length of the partially oxidized GQDs, ranging from M=4 to 7.
采用含杂化交换项的 Heyd-Scuseria-Ernzerhof（HSE06） screened 交换泛函密度泛函理论（DFT），对锯齿形边缘氧化石墨烯量子点（GQDs）的电子性质和半金属性质进行了全面的第一性原理理论研究。氧化方案包括-OH、-COOH 和-COO 基团。我们确定了一些氧化 GQDs，其相反自旋在反铁磁型结构中定域在两个锯齿形边缘，呈现出自旋极化的基态。氧化 GQDs 比相应的完全氢化 GQDs 更稳定。具有相同尺寸的部分羟基化和羧基化 GQDs 在几乎相同的电场强度下表现出半金属态，而完全氧化的 GQDs 则表现为自旋选择半导体。诱导半金属的电场强度随部分氧化 GQDs 的长度增加而增加，范围从 M=4 到 7。
