新型含咔唑聚芴类共轭聚电解质及其前驱体的合成与光电性能

采用Suzuki偶合反应成功地合成了一系列在主链上具有不同含量苯并噻二唑单元的聚咔唑和含胺基芴的衍生物:聚[3,6-(N-(2-乙基己基))咔唑-2,1,3-苯并噻二唑-9,9-双(N,N-二甲基胺丙基)芴](PCzN-BTDZ);通过对所得聚合物的季铵盐化后处理得到了其相应的聚电解质衍生物:聚[3,6-(N-(2-乙基己基))咔唑-2,1,3-苯并噻二唑-9,9-(双(3′-(N,N-二甲基)-N-乙基铵)丙基)芴]二溴(PCzNBr-BTDZ)。通过对它们的电致发光性能的研究,发现所有的聚合物用高功函数铝作阴极的器件具有和用钡/铝作阴极的器件相近的发光性能,说明这类聚合物具有良好的电子注入性能。不同比例的2,1,3-苯并噻二唑(BTDZ)的引入使聚合物中发生有效的能量转移,调节了聚合物的发光颜色;同时也提高了聚合物的器件性能。其中聚合物PCzN-BTDZ1在器件结构为ITO/PEDOT/PVK/Polymer/BaAl时的效率达0.99%,高于PCzN在相同器件结构时的效率(0.14%)。     

高效饱和红光聚电解质的发光及电子注入特性研究

以新型的环境友好的水/醇溶性胺基化或者季铵盐化的芴和含硫窄带隙共聚物4,7-二噻吩-2-基-2,1,3-苯并噻二唑的共轭聚电解质为发光层,以高功函数金为电极,制备了一系列高效饱和红色单层发光二极管. 对PFN-DBT10,在38.7mA/cm²下外量子效率达到0.42%,色坐标位于(0.67,0.33). 这类聚电解质解决了发光器件层间的互溶问题,以它和高功函数金组成双层复合阴极,制成了高效三基色双层发光二极管. 通过单层和双层器件结构系统地研究了这类新型聚电解质的发光特性和电子注入特性,器件效率的提高与这类聚电解质和高功函数金电极界面相互作用有关.     

Direct visualization of the charge transfer in conjugated polymers

Ion-induced charge-transfer states in conjugated polyelectrolytes were experimentally investigated by Justin M.Hodgkiss and his co-workers [J Am Chem Soc,2009,131(25):8913].In this work,charged and neutral conjugated polyelectrolytes were further studied with quantum chemistry methods.The calculation result shows that the absorption spectra are roughly in visible and ultraviolet light regions,and the two absorption peaks are located in the wavelength span 300-400 nm for charged polyelectrolytes.However,in n...     

乙醇做碳源Mo-Co/MgO做催化剂合成单壁碳纳米管

本文采用柠檬酸法制备Mo-Co/MgO催化剂, 在小型流化床中, 以Ar气为载气直接携带乙醇蒸汽进入反应器, 通过化学气相沉积（CCVD）技术来合成制备单壁碳纳米管（SWCNTs）。利用扫描电镜和拉曼光谱方法研究了催化剂组分比例和载气流量等对SWCNTs制备的影响。研究结果表明: 以乙醇做碳源, Mo1-Co10/MgO做催化剂, Ar气流量为150sccm时制备的单壁碳纳米管质量最佳。     

Fabrication of thin-film transistor based on self-assembled single-walled carbon nanotube network

Thin-film transistor based on controllable electrostatic self-assembled monolayer single-wall carbon nanotubes (SWNTs) network has been fabricated by varying the density of nanotubes on the silicon substrate. The densities of SWNTs network have been investigated as a function of concentration and assembly time. It has been observed that the density of SWNTs network increases from 0.6 µm⁻² to 2.1 µm⁻², as the average on-state current (I_on) increases from 0.5 mA to 1.47 mA. The device has a current on/off ratio (I_on/I_off) of 1.3×10⁴ when I_on reaches to 1.34 mA.     

Adsorption of pairs of NOx molecules on single-walled carbon nanotubes and formation of NO + NO3 from NO2

The adsorption of NO_x(x = 1, 2, 3) molecules on single-walled carbon nanotubes (SWCNTs) is investigated using first-principle calculations. Single NO, NO₂ and NO₃ molecules are found to physisorb on SWCNTs, but molecules can be chemisorbed in pairs on the top of carbon atoms at close sites of SWCNTs. The adsorption energy for pairs of NO or NO₃ molecules is larger than for pairs of NO₂ molecules. The local curvature is found to have a sizable effect on adsorption energies. The possibility of a surface reaction NO₂ + NO₂ → NO + NO₃ is examined and the relative pathway and barrier is calculated. The results are discussed with reference to available experimental results.     

热电材料与发电器件的进展和挑战

热电/温差电效应是一种能够实现热能和电能直接相互转换的环境友好型能源技术,基于该技术的热电发电器件的应用,有望成为缓解能源问题的可行方案。文章主要介绍了中高温区p型和n型热电材料的最新研究进展,重点论述了可能应用于热电发电器件的几种典型热电材料体系的相关优缺点。此外,还回顾了目前中高温区热电发电器件的研究现状,尝试给出了目前亟待突破的壁垒,最后讨论并展望了热电发电器件的发展前景与未来研究方向。     

水对800℃下CH4在Ar气中分解制备单壁碳纳米管的影响

利用透射电子显微镜和拉曼光谱方法研究了水对800℃下Ar气中催化分解CH4制备单壁碳纳米管（SWCNTs）的影响.结果表明,反应气中少量水（室温下反应气的湿度约5%）的引入提高了产物中SWCNTs的含量.初步分析认为,水在反应过程中起到了提纯作用,从而降低无定形碳生成率.此外,还发现水的引入缩小了产物中SWCNTs的管径分布.关键词：单壁碳纳米管水拉曼光谱     

温差电技术原理及在工科物理实验中的应用

简要介绍温差电技术的基本原理以及运用该原理设计、制作一些在工科物理实验中的装置。     

NaxCoO2晶体的制备、结构和物性

本文以氢氧化钠(NaOH)为溶剂,用高温溶液电解法成功生长出了α相和γ相的NaxCoO2单晶.通过少量SrCO3的添加,可以人为控制晶体产品的晶体学相.以NaOH为溶剂生长出γ相NaxCoO2晶体,添加SrCO3则生长出α相NaxCoO2晶体.对单晶样品的电阻率的测量发现,α相NaxCoO2的电阻率随温度降低而升高,呈半导体特性,而γ相NaxCoO2的电阻率则随温度降低而降低,呈金属性.α相NaxCoO2的热电势低于同温度下γ相NaxCoO2热电势,在300K时分别为30μV/K和70μV/K左右,但均随温度降低而减小,即热电势的温度关系均表现为金属型行为.     

Sn-based type-VIII single-crystal clathrates with a large figure of merit

Single-crystal samples of type-VIII Ba 8 Ga 16 x Cu x Sn 30 (x=0,0.03,0.06,0.15) clathrates were prepared using the Sn-flux method.At room temperature the carrier density,n,is 3.5-5×10～(19)cm～3 for all the samples,the carrier mobility,μ H,increases to more than twice that of Ba 8 Ga 16 Sn 30 for all the Cu doping samples,and consequently the electrical conductivity is enhanced distinctly from 1.90×10～4 S/m to 4.40×10～4 S/m,with the Cu composition increasing from x=0 to x=0.15.The Seebeck coefficient,α,decreases slightly with the increases in Cu composition.The κ values are about 0.72 W/mK at 300 K and are almost invariant with temperature up to 500 K for the samples with x=0 and x=0.03.The lattice thermal conductivity,κ L,decreases from 0.59 W/mK for x=0 to 0.50 W/mK for x=0.03 at 300 K.The figure of merit for x=0.03 reaches 1.35 at 540 K.     

热电发电机驱动热电制冷机联合系统最优性能

用非平衡热力学与有限时间热力学相结合的方法,考虑装置内部的Seebeck效应、Peltier效应、焦耳热效应、傅立叶效应及装置与热源间传热损失,建立了牛顿传热规律下热电发电机驱动热电制冷机联合系统的有限时间热力学模型,得到装置制冷率和制冷系数的解析式.在装置热电单元总数和换热器总换热面积一定的条件下,优化热电单元和换热面积的分配,获得装置的最大制冷率和制冷系数,并着重分析了热电发电机高温热源温度和热电制冷机制冷空间温度对装置最优性能的影响.结果表明,优化可以有效地提高装置制冷率和制冷系数,增大装置极限制冷温差,拓宽装置工作范围.