氧化石墨烯热电性质的理论研究

项目名称： 氧化石墨烯热电性质的理论研究

项目编号： No.11504041

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 周思

作者单位： 大连理工大学

项目金额： 21万元

中文摘要： 近年来，石墨烯的热电性能逐渐成为研究热点。石墨烯具有高电导率(σ)和热导率(κ)，以及较低的Seebeck系数(S)，其自身热电性能并不优越。对石墨烯进行氧化可以有效调控其电学和热学性质，所得的产物—氧化石墨烯(GO)在热电材料应用领域具有很大的潜力。然而，如何针对GO的热电应用，调节其化学组分和原子结构，在σ,κ和S这三个相互冲突的物理量中获得最优的平衡，目前尚不清楚。本项目拟利用密度泛函理论计算、非平衡格林函数法、和非平衡分子动力学模拟，系统研究氧化石墨烯的热电性质，阐明GO的电导、Seebeck系数和热导率随含氧官能团的种类、浓度和分布的变化规律，通过考察GO的电子和声子能带结构以揭示这种关联下的微观物理机制，识别具有良好热电性能的氧化石墨烯的化学特征和结构特征，建立提高其热电品质因子的普适性方法，为实验设计和制备可应用的石墨烯/类石墨烯热电材料提供有价值的理论指导。

中文关键词： 氧化石墨烯；热电性质；密度泛函理论；分子动力学模拟；非平衡格林函数法

英文摘要： The thermoelectric property of graphene has become a hot topic in recent years. Graphene intrinsically has exceptional high electrical (σ) and thermal conductivity (κ), low Seebeck coefficient (S), and thus shows limited thermoelectric figure of merit (ZT). Graphene oxide (GO), a chemically modified form of graphene, has tunable electronic and thermal properties, and is a potential candidate for thermoelectrics. However, little is known about how to balance the three conflicting parameters, i.e.,σ,κ,S,by controlling the chemistry and structure of GO to improve its ZT value. In this project, we will investigate the thermoelectric properties of graphene oxide based on density functional theory calculations, nonequilibrium Green function method, and nonequilibrium molecular dynamics simulations. We aim to clarify the dependence of electrical conductance, Seebeck coefficient, and thermal conductivity on the concentration and distribution of oxygenate groups on GO. Meanwhile, we will unravel the underlining mechanism by exploring the electron and phonon band structures of GO. Our goal is to identify the chemical and structural features of graphene oxide that processes high ZT values, and develop effective methods to improve the thermoelectric performance of GO. Our theoretical work will provide guidance for experimental design and fabrication of graphene-based materials of high thermoelectric efficiency.

英文关键词： graphene oxide;themoelectric properties;density functional theory;molecular dynamic simulation;nonequilibrium Green function method