新型石墨烯分子器件热电性能及纳米界面上的输运过程研究

项目名称： 新型石墨烯分子器件热电性能及纳米界面上的输运过程研究

项目编号： No.51202032

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 无机非金属材料学科

项目作者： 徐兰青

作者单位： 福建师范大学

项目金额： 24万元

中文摘要： 石墨烯具有巨热电效应，利用单分子连接石墨烯带设计的分子器件可以在降低纯石墨烯高热导的同时又保留高热电功率因子，已成为石墨烯器件设计的一个新方向。本项目主要采用基于密度泛函理论的第一性原理和非平衡格林函数方法，分析由石墨烯和不同连接单元组成的新型分子器件的热电性能参数和纳米连接点上的输运动力学过程。从计算中获取界面处不同原子成键结构、电子结构、带隙、费米能级移动、声子散射等，研究结构中纳米界面上的电子和声子输运过程和迅逝波的耦合效率，分析各因素之间的相关性及其对热电功率、电导和热导的影响，探索分子结构和界面诱导下高功率因子低热导的形成原因，获得不同构型下热电性能参数的变化规律，为面向热电应用的新型分子电子器件设计提供理论基础。

中文关键词： 热电性能；热输运；第一性原理；非平衡格林函数；石墨烯

英文摘要： By attaching a single molecular to two grapheme nanoribbons a new class of thermoelectric devices, termed graphene-based molecular device, can be designed, which is found to reduce the high thermal conductivity of pristine graphene and meanwhile maintaining its high power factor. Due to its nanosize and fascinating performance, this type of device has intriguing future in nanoelectronic and thermoelectric applications. Currently, there are limited studies on the thermoelectric performance of graphene-based molecular device, and fewer on how the high electronic transmission rate and low phonon propagation efficiency emerge. In this project, the PI proposes to investigate the transport dynamics on the single-molecular nanojunction and the thermoelectric properties in a series of thermoelectric nanodevices constructed from various molecular types and different molecular sizes. Density-functional theory (DFT) and non-equilibrium Green's function (NEGF) will be adopted. The mechanisms underpinning structure-induced high power factor as well as low thermal conductivity in the novel devices will be explored. Thermopower, electronic conductivity, thermal conductivity and other related parameters will be obtained and possible rules will be presented. The outcomes from this project can serve to guide the design in novel t

英文关键词： thermoelectric properties；thermal transport；first-principles method；non-equilibrium Green's function；graphene