石墨烯-C70基纳米复合结构场发射性能研究

发布时间：2018-01-04 23:25

本文关键词：石墨烯-C70基纳米复合结构场发射性能研究　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：由于阴极材料在场发射显示屏的发展和应用中占据重要地位,使得阴极材料的场发射特性研究变得十分重要,对阴极材料的探索研究也成为推动了场发射显示屏发展的核心工作,而石墨烯凭借其优异的结构特性和电子特性,已经成为新一代能取代金属尖端的具有巨大潜力的场发射阴极材料。为进一步开发并提高石墨烯在场发射领域的应用潜力和商业价值,研究者们将石墨烯与其他热门研究的场发射阴极材料进行复合,从而人工合成为性能更优异的阴极材料。为此,顺应研究的发展趋势,本文通过对石墨烯和其他碳材料进行复合后的场发射特性进行模拟研究,期望获得比原石墨烯材料更为优异的场发射特性,论文的研究内容可分为以下几点:(1)运用Material Studio建立了石墨烯-C70复合结构模型,并通过Material Studio的DMOL3模块对不同应用电场下的石墨烯-C70复合结构进行维纳尺度的模拟计算研究。在此,本文计算了不同电场下石墨烯-C70复合结构的结合能、功函数、离化能和电子亲和性,并分析了它的不同电场下的分子轨道能级和电子密度分布的变化趋势。结果表明,石墨烯-C70复合材料的结合能随着电场的施加并增强而降低,这表明复合结构在电场的施加并增强的条件下越来越稳定,这满足计算其他参数随电场的变化趋势的稳定性要求。其次,复合材料的功函数和离化能随着电场的增强而降低,这表明电子发射变得更容易。在电场的作用下,电子轨道能级逐渐靠近真空能级且它们的能隙也有下降的趋势。这对于提高材料的场发射特性是很好的趋势,说明石墨烯-C70复合材料具有优秀的的场发射特性和作为阴极材料的应用潜力。(2)在石墨烯-C70复合结构的基础上,掺杂一个B原子对其进行改性,来进一步提高场发射特性。在此,本研究在C70顶端和石墨烯与C70连接处选择了7种不同位置作为B原子的掺杂点,从而得到7种不同的B掺杂石墨烯-C70复合结构。通过计算这7种B掺杂石墨烯-C70复合结构的结合能、功函数、离化能、电子亲和性,并与原石墨烯-C70复合结构进行对比,分析掺杂对分子轨道能级的影响,以观察B原子的掺入对石墨烯-C70复合结构的改进情况。结果表明掺入B原子并未改变原复合结构的结合能、功函数、离化能、电子亲和性以及分子轨道能级等随电场的变化趋势,相反,这些性能都得到巨大的改善,从而提高了石墨烯-C70复合结构的场发射性能。(3)与B掺杂复合结构的掺杂方式和掺杂位置相同,本研究对石墨烯-C70复合结构的7个位置分别掺入N原子,从而建立了7种不同的N掺杂石墨烯-C70复合结构。为了方便与B掺杂复合结构进行对比,在相同的电场下,计算了结合能、功函数等用于评价材料场发射特性的指标,同时也分析了N掺杂复合结构在不同电场下的分子轨道能级。结果证明掺入N原子后的性能有许多方面优于原石墨烯-C70复合结构却略逊色于B掺杂复合结构。
[Abstract]:Due to occupy an important position in the development and application of cathode material of field emission display, which makes the research of field emission characteristics of the cathode material has become very important, the research on cathode materials has become the core work to promote the development of the field emission display, and graphene by virtue of its excellent structural properties and electronic properties, has become a new generation replace the metal tip potential field emission cathode materials. For the further development and improvement of graphene field emission application potential and commercial value, the researchers will graphene and other hot research field emission cathode composite materials, and synthesized as cathode material with more excellent properties. Therefore, comply with the development trend the research, based on graphene and other carbon composite materials after the field emission characteristics were simulated, expect to get rough than graphene The material is more excellent field emission properties, the research contents of this paper can be divided into the following points: (1) using Material Studio to establish the graphene -C70 composite structure model, and through the DMOL3 module of Material Studio graphene -C70 composite structure is applied to calculate the electric field simulation of nano scale dimension. Then, this paper calculated the combination of graphene -C70 composite structure under different electric field energy, work function, ionization energy and electron affinity, and the analysis of the molecular orbital and electron density distribution of the variation trend of it under different electric field. The results show that the combination of graphene -C70 composite material with an applied electric field and enhanced this shows that the composite structure is reduced, and enhanced in the applied electric field under the condition of more and more stable, which meet the stability calculation of other parameters change with electric field requirements. Secondly, the work function and composite materials The ionization energy decreased with the increase of the electric field, which indicates that the electron emission easier. Under the action of electric field, electron orbitals gradually close to the vacuum level and the gap is also a downward trend. To improve the field emission properties of materials is a good trend, that graphene -C70 composite has the excellent field emission characteristics and potential applications as cathode materials. (2) based on graphene -C70 composite structure, modification of the doped B atoms, to further improve the field emission characteristics. Here, this study at the connection between the C70 and the top of graphene and C70 chose 7 different as the doping of B atom, obtained 7 kinds of B doped graphene -C70 composite structure. By calculating the combination of these 7 kinds of B doped graphene -C70 composite structure, work function, ionization energy, electron affinity, and composite with rough graphene -C70 Structure comparison, analysis the influence of doping on the molecular orbital energy, in order to observe the incorporation of B atoms on the modified graphene -C70 composite structure. The results showed that the incorporation of B atoms do not change with the original composite structure, work function, ionization energy, electron affinity and molecular orbital with the trend. The electric field on the contrary, these properties have been greatly improved, thus improving the graphene -C70 composite structure of field emission performance. (3) and doped B doped composite structure and doped with the same position, the research on the position of the 7 graphene -C70 composite structure of the doped N atoms, and establish 7 N doped graphene -C70 composite structure is different. For the convenience of B doped composite structure were compared, in the same field, binding energies were calculated, the work function for field emission materials evaluation index, also analyzed the N doping The composite structure of molecular orbital energy levels in different fields. The results showed that the incorporation of N atoms has many properties than the rough graphene -C70 composite structure is slightly less than B doped composite structure.

【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TB33

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