利用第一原理計算AA堆疊石墨烯之光學性質與分子動力學計算聚氧乙烯之熱學性質

Abstract

電腦建模已經成為模擬複雜系統的強大且可靠的一項工具。本論文使用密度泛函理論探討單層和AA堆疊之雙層石墨烯之間的電子和光學性質之差異。發現了AA堆疊的雙層石墨烯具有能帶，而單層石墨烯不具有能隙。隨著內層之間距越大，能隙值隨之降低。此外，亦發現了AA堆疊的雙層石墨烯的各向異性介電常數。除了探討複合材料的熱力學和機械性質，分子動力學被用於研究聚環氧乙烷。使用聚環氧乙烷模擬單體、冷卻速率、鏈數的現象。發現了高分子材料對於系統原子數與結構弛豫時間有高度的相依性。最後，本論文探討了聚環氧乙烷和石墨烯的複合材料，並從中瞭解差異性。

Computer modeling has become a powerful and reliable tool for simulating complex systems. In this thesis, density functional theory is used for realizing the difference of electronic and optical properties between single layer and AA-stacked bilayer graphene. It is found out that AA-stacked bilayer graphene has band gap but single layer graphene doesn’t. The larger distance between interlayer is, the smaller bandgap value is. Also, the anisotropic permittivities of AA-stacked bilayer graphene are demonstrated. In addition, to understand the thermal and mechanical properties of composite material, molecular dynamics are used for studying on poly (ethylene oxide) and monomer layer graphene. The monomer, cooling rate, chain number effects are demonstrated using pristine poly (ethylene oxide). It is found out that the polymer system is strongly depended on both number of atoms and structural relaxation time. Finally, the composite material of poly (ethylene oxide) and graphene is discussed and realized the differences.