Theoretical Study of Single-molecule Electron Transport by Combining Density Functional Theory and Non-equilibrium Green’s Function Approach

分子电子器件因为在电子学领域中具有潜在的应用价值而倍受学术界关注，有望成为新一代的电子器件。电子在分子结的传输是分子电子学领域的研究核心。然而，实验和理论上给出的电导值却有很大差别，这是该领域亟待解决的问题。在本论文中，我们选取了三种类型的分子，分别是具有非共轭性质的烷基链分子、具有共轭性质的oligo(1，4-phenylene-ethynylene)s(OPEs)分子和1，4-benzene-di(n-alkylthiol)(BDnT)分子。这三类分子可以用三种Simmons模式来表示。为了揭示理论与实验之间存在差异的原因，通过运用基于第一性原理的密度泛函理论（DensityFunctio...Electron transport through molecular junctions is highly important and of potential applications for the next generation electronics, and therefore has been widely investigated both experimentally and theoretically. Unfortunately, there exists discrepancy on the single molecular conductance between theoretical calculations and experimental measurements. Clarifying the origin leading to such a disc...学位：理学硕士院系专业：化学化工学院_物理化学学号：2052013115164

Mechanism and Characterization of Electron Transport Through Metal/Molecule/Metal Junctions

金属/分子/金属结是分子电子学中的基本单元.根据电子的相位是否发生改变,分子结中的电子输运可以分为相干输运和非相干输运两类.在实验上,分子结的表征方法可以分为电学性质表征和非电学性质表征两类.本文借助能级图,首先对分子结的电子输运机理作了简明解释.在此基础上,结合文献报道和本课题组此前的工作,对分子结的一些常用电学表征方法,包括电流-电压特性曲线、电流-时间曲线、电导统计柱状图、转变电压谱、散粒噪声测试、非弹性电子隧道谱和热电效应法进行了介绍.Although molecular electronics emerged several decades ago,it is still concerning about fundamental issues so far.Metal/molecule/metal junction is a conceptually basic unit in molecular electronics.The mechanism of electron transport through metal/molecule/metal junction has attracted great interest.In general,the mechanisms for electron transport through metal/molecule/metal junctions can be divided into two categories: coherent transport and non-coherent transport according to the phase change of tunneling electrons.In this review,the electron transport mechanism is illustrated briefly by employing energy diagrams.Moreover,several extensively measured approaches for studying metal/molecule/metal junctions,including I-V characteristic curve,I-t trace and conductance histogram,transition voltage spectroscopy,shot noise,inelastic electron tunneling spectroscopy,and thermoelectricity are introduced through referring to some recent publications including our works.科技部-国家重大科学仪器设备开发专项项目(批准号:2011YQ030124); 国家自然科学基金(批准号:21321062;21373172)资助~

新疆棉花、小麦蚜虫生态治理技术

深入研究并充分利用农业害虫的自然控制因素，结合新疆农业系统中特有的自然生态条件特点，对害虫实施生态控制。发现麦双尾蚜的天敌100种，筛选出了低感虫品种、高感虫品种和耐害品种共15个，发现了具有潜在威胁的2个新物种，制订了以调整冬春麦种植结构和保护天敌为核心的麦双尾蚜自控防治技术和策略。可以利用苜蓿带自然繁育天敌可以用于控制棉蚜的生物学机理，即“苜蓿与棉花具有不同的主要昆虫种类，但具有相同的主要天敌类群”。提出了麦双尾蚜生物型演变成灾假说，提出“植物应该并且可以作为生物防治的重要因素加以利用”的观点，提出“相生植保”思路，创制新疆棉蚜生态控制技术体系，提出“新疆发展农区畜牧业、实现棉花害虫生态治理”应用模式