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利用第一性原理方法, 采用超软赝势库系统研究了硝酸熏蒸石墨烯得到的氧化石墨烯结构的稳定性及电子结构. 基于石墨烯正交元胞的2 × 2超胞模型建立相应的正交晶系硝酸熏蒸氧化石墨烯模型, 包含15个碳原子和2个氧原子. 结果表明熏蒸后包含碳氧双键的氧化石墨烯结构为能量较低的稳定结构, 与实验报道一致. 力学稳定性分析表明该结构的
C_66 > 0,\;C_11 > 0,\;C_11C_22 > C_12^2 , 处于力学稳定状态. 通过分析熏蒸前后的反应物和生成物, 表明硝酸起催化作用; 且硝酸氧化石墨烯为吸热过程, 反应发生需要外界热源. 通过分析结构的电子特性, 得出氧化石墨烯为直接带隙本征半导体, 带隙值为1.12 eV, 功函数为5.28 eV. 研究结果为硝酸氧化石墨烯的制备及其在光电子器件领域的应用提供了理论依据.The stability and electronic structure properties of graphene fumigated by nitric acid are systematically studied by the first-principles method based on ultrasoft pseudopotentials. The model of graphene oxide fumigated by nitric acid is built based on the 2 × 2 supercell model with orthogonal graphene unit cells, which contains 15 carbon and 2 oxygen atoms. The results show that the fumigated graphene containing a carbon atom bonded to an oxygen atom is a stable structure with lower energy, which is consistent with the experimental result. In addition, the mechanical stability analysis showsC_66 > 0,\;C_11 > 0,\;C_11C_22 > C_12^2 , which satisfies the mechanical stability condition. By analyzing the reactant and product, it can be concluded that the nitric acid acts as catalyst. Moreover, the process of graphene oxidation catalyzed by nitric acid is endothermic and the reaction needs heating. By analyzing the electronic properties of the structure, the graphene oxide is determined to be an intrinsic semiconductor with a direct band gap of 1.12 eV and work function of 5.28 eV. These results provide theoretical basis for preparing the graphene oxide and its applications in the field of optoelectronic devices.-
Keywords:
- first-principles calculation /
- graphene oxide /
- catalytic










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