基于密度泛函理论的单层氢化石墨烯特性分析

本文采用密度泛函理论的第一性原理方法,研究了不同尺寸H-graphene的稳定性、HOMO-LU-MO能隙以及电子激发态.研究结果表明,对于C_(16)H_(10)、C_(30)H_(14)、C_(48)H_(18)、C_(70)H_(22)、C_(96)H_(26)、C_(126)H_(30)计算的比结合能,C_(126)H_(30)相比C_(16)H_(10)的比结合能增长23.9%,且比结合能随着H-graphene尺寸扩大而增加,意味着稳定性不断提高.通过对HOMO-LUMO能隙分析发现,在较小尺寸的H-graphene中,由于量子效应起主要作用,因此出现了较大的HOMO-LUMO能隙,且随着H-graphene团簇尺寸的增加,能隙逐渐缩小可以看出,对于无限大的H-graphene团簇中,HOMO-LUMO能隙无限趋近于零(相当于零带隙),其电子性质与纯石墨烯相似.通过分析C_(16)H_(10)、C_(30)H_(14)、C_(48)H_(18)、C_(70)H_(22)激发态以及了吸收光谱,发现随着尺寸的扩大,吸收光谱发生红移,为石墨烯在电子器件领域的应用提供理论基础.

Characteristic analysis of single-layer hydrogenated graphene based on density functional theory

This paper uses the first-principles method of density functional theory to study the stabilities, HOMO-LUMO energy gaps, and electronically excited states of different sizes of H-graphene. The results show that in the calculated specific binding energy of C16H10, C30H14, C48H18, C70H22, C96H26 and C126H30, the specific binding energy of C126H30 is larger by 23.9% than that of C16H10, and it increases with the expansion of the H-graphene size, which means that the stability is continuously improved. Through the analysis of the HOMO-LUMO energy gap, it is found that in the smaller size of H-graphene, due to the quantum effect playing a major role, a larger HOMO-LUMO energy gap appears, and as the size of the H-graphene cluster increases, the energy gap gradually shrinks. It can be seen that for the infinite H-graphene clusters, the HOMO-LUMO energy gap is infinitely close to zero (equivalent to zero bandgaps), and its electronic properties are similar to those of pure graphene. Through the analysis of C16H10, C30H14, C48H18, C70H22 excited states, and absorption spectra, it is found that as the size increases, the absorption spectrum has a redshift, providing a theoretical basis for the application of graphene in the field of electronic devices.