The synthesis of MDMO-PPV capped PbS nanorods and their application in solar cells

Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) capped PbS nanorods about 100 nm in diameter and 400 nm in length were synthesized via a hydrothermal route in toluene and dimethylsulfoxide solution. By blending the PbS nanorods with the MDMO-PPV as the active layer, bulk heterojunction solar cells with an indium tin oxide (ITO)/polyethylenedioxythiophene/polystyrenesulphonate (PEDOT PSS)/MDMO-PPV PbS nanorods/Al structure were fabricated in a N-2 filled glove box, Current density-voltage characterization of the devices showed that the solar cells with PbS nanorods hybrid with MDMO-PPV as active layer were better in performance than the devices with the polymer only. (C) 2009 Elsevier B.V. All rights reserved.

Light extraction of GaN LEDs with 2-D photonic crystal structure

Ultraviolet photo-lithography is employed to introduce two-dimensional (2D) photonic crystal (PC) structure on the top surface of GaN-based light emitting diode (LED). PC patterns are transferred to 460-nm-thick transparent indium tin oxide (ITO) electrode by inductively coupled plasma (ICP) etching. Light intensity of PC-LED can be enhanced by 38% comparing with the one without PC structure. Rigorous coupled wave analysis method is performed to calculate the light transmission spectrum of PC slab. Simulation results indicate that total internal reflect angle which modulated by PC structure has been increased by 7 degrees, which means that the light extraction efficiency is enhanced outstandingly.

Proof of solid state cathodoluminescence by using brightness waveform

Three different inorganic-organic hetero-junctions (A : ITO/SiO2/Alq(3)/Al, B: ITO/Alq3/SiO2/Al and C: ITO/SiO2/Alq(3)/ SiO2/Al) were fabricated. The emission can be observed only under positive bias in devices A and B, but under both biases in device C according to their brightness waveforms. With increasing voltage, the increase in blue emission in devices B and C is faster than that in green emission. This is because that the recombination of hot electrons and holes, i.e., electron-hole pairs, produced blue emission in devices B and C, and the recombination of electrons injected from Al with the accumulated holes, which are excited by hot electrons, produced green emission in device A. Hence, the emissions of the devices are attributed to not only the recombination of electrons and accumulated holes, but also the cathodoluminescence-like (CL-like) emission.

Fabrication of ZnO and its enhancement of charge injection and transport in hybrid organic/inorganic light emitting devices

ZnO nanocrystals were synthesized by hydrolysis in methanol. X-ray diffraction and photoluminescence spectra confirm that good crystallized ZnO nanoparticles were formed. Utilizing those ZnO nanoparticles and poly [2- methoxy-5 - (3',7'-dimethyloctyloxy)- 1,4-phenylenevinylene] (MDMO-PPV), light emitting devices with indium tin oxide (ITO)/poly(3,4-oxyethyleneoxy-thiophene):poly(styrene sulfonate) (PEDOT:PSS)/ ZnO:MDMO-PPV/Al and ITO/PEDOT:PSS/MDMO-PPV/Al structures were fabricated. Electrolummescence (EL) spectra reveal that EL yield of hybrid MDMO-PPV and ZnO nanocrystals devices increased greatly as compared with pristine MDMO-PPV devices. The current-voltage characteristics indicate that addition of ZnO nanocrystals can facilitate electrical injection and charge transport. The decreased energy barrier to electron injection is responsible for the increased efficiency of electron injection. (c) 2007 Elsevier B.V. All rights reserved.

Improved performance in organic light emitting diodes with a mixed electron donor-acceptor film involved in hole injection

Organic light emitting diodes using a mixed layer of electron acceptor 3, 4, 9, 10 perylenetetracarboxylic dianhydride and electron donor copper phthalocyanine (PTCDA:CuPc) on indium tin oxide (ITO) anodes were fabricated. The device properties were found to be strongly dependent on the thickness of the PTCDA:CuPc film: both the power efficiency and the driving voltage of the device were optimized with a thickness of PTCDA:CuPc ranging from 10 to 20 nm. As compared to the conventional ITO/CuPc hole injection structure, the ITO/PTCDA:CuPc hole injection structure could remarkably enhance both the luminance and the power efficiencies of devices. A mechanism of static-induced, very efficient hole-electron pairs generation in mixed PTCDA:CuPc films was proposed to explain the experimental phenomena. The structural and optical properties of PTCDA:CuPc film were examined as well. (c) 2007 American Institute of Physics.

XPS depth profiling study of n/TCO interfaces for p-i-n amorphous silicon solar cells

Detailed X-ray photoelectron spectroscopy (XPS) depth profiling measurements were performed across the back n-layer/transparent conducting oxide (n/TCO) inter-faces for superstrate p-i-n solar cells to examine differences between amorphous silicon (a-Si:H) and microcrystalline silicon (mu c-Si:H) n-layer materials as well as TCO materials ZnO and ITO in the chemical, microstructural and diffusion properties of the back interfaces. No chemical reduction of TCO was found for all variations of n-layer/TCO interfaces. We found that n-a-Si:H interfaces better with ITO, while n-mu c-Si:H, with ZnO. A cross-comparison shows that the n-a-Si:H/ITO interface is superior to the n-mu c-Si:H/ZnO interface, as evidenced by the absence of oxygen segregation and less oxidized Si atoms observed near the interface together with much less diffusion of TCO into the n-layer. The results suggest that the n/TCO interface properties are correlated with the characteristics of both the n-layer and the TCO layer. Combined with the results reported on the device performance using similar back n/TCO contacts, we found the overall device performance may depend on both interface and bulk effects related to the back n/TCO contacts. (c) 2006 Elsevier B.V. All rights reserved.

Nanocrystalline silicon films with high conductivity and the application for PIN solar cells

Intrinsic nanocrystalline silicon films (nc-Si:H) were prepared by plasma enhanced chemical vapor deposition (PECVD) method. Films' microstructures and characteristics were studied with Raman spectroscopy and Atom Force Microscope (AFM). The electronic conductivity of nc-Si:H films was found to be 4.9 x 10(0)Omega(-1) cm(-1), which was one order of magnitude higher than the reported 10(-3)-10(-1)Omega(-1)cm(-1). And PIN solar cells with nc-Si:H film as intrinsic thin-layer (ITO/n(+)-nc-Si:H/i-nc-Si:H/p-c-Si/Ag) were researched. The cell's performances were measured, the open-circuit voltage V-oc was 534.7 mV, short-circuit current I-sc was 49.24 mA (3 cm(2)) and fill factor FF was 0.4228. (c) 2006 Elsevier Ltd. All rights reserved.

Influence of indium-tin-oxide thin-film quality on reverse leakage current of indium-tin-oxide/n-GaN Schottky contacts

Indium-tin-oxide (ITO)/n-GaN Schottky contacts were prepared by e-beam evaporation at 200 degrees C under various partial pressures of oxygen. X-ray photoemission spectroscopy and positron beam measurements were employed to obtain chemical and structural information of the deposited ITO films. The results indicated that the observed variation in the reverse leakage current of the Schottky contact and the optical transmittance of the ITO films were strongly dependent on the quality of the ITO film. The high concentration of point defects at the ITO-GaN interface is suggested to be responsible for the large observed leakage current of the ITO/n-GaN Schottky contacts. (c) 2006 American Institute of Physics.

Synthesis and structures of morphology-controlled ZnO nano- and microcrystals

Zinc oxide flower-like bunches were directly synthesized on indium-doped tin oxide (ITO) glass substrates through a simple chemical bath deposition process. By adjusting precursor concentration, other morphologies ( spindles and rods) were also obtained. All of them are hexagonal and single crystalline in nature and grow along the [ 0001] crystallographic direction. The possible growth mechanisms for these nano- and microcrystals were proposed. It was revealed that both the inherent highly anisotropic structure of ZnO and the precursor concentration play crucial roles in determining final morphologies of the products. In addition, vibrational properties of ZnO crystals with different morphologies were investigated by Raman spectroscopy.

Novel photonic crystal structure GaN-based light-emitting diodes - art. no. 68410J

For enhancing the output efficiency of GaN light-emitting diode(LED), we calculated the band structure of photonic crystal(PhC), and designed and fabricated several novel GaN LEDs with photonic crystal on Indium-Tin-Oxide(ITO), which as p-type transparent contact of GaN LED. In this fabricating process, we developed conventional techniques in order that these methods can be easily applied to industrial volume-production. And we have done some preliminary experiments and obtained some results.

Highly efficient and stable organic light-emitting diodes employing MoO3-doped perylene-3, 4, 9, 10-tetracarboxylic dianhydride as hole injection layer

We report highly efficient and stable organic light-emitting diodes (OLEDs) with MoO3-doped perylene-3, 4, 9, 10-tetracarboxylic dianhydride (PTCDA) as hole injection layer (HIL). A green OLED with structure of ITO/20 wt% MoO3: PTCDA/NPB/Alq(3)/LiF/Al shows a long lifetime of 1012 h at the initial luminance of 2000 cd/m(2), which is 1.3 times more stable than that of the device with MoO3 as HIL. The current efficiency of 4.7 cd/A and power efficiency of 3.7 lm/W at about 100 cd/m(2) have been obtained. The charge transfer complex between PTCDA and MoO3 plays a decisive role in improving the performance of OLEDs.

基于PAR的高可信装备保障算法推演

算法被誉为计算的“灵魂”（spirit of computing），算法程序的可靠性和正确性对软件系统的可信度起着至关重要的作用。动态规划、贪心、分支限界等传统的算法设计策略缺乏有效的选择标准，一些算法形式化开发方法和工具的应用水平和范围也很有限，因此算法的可靠性已成为高可信软件系统的一个主要瓶颈。 作为军事运筹学的一个重要分支，装备保障计算主要研究军事活动中装备领域的决策优化问题，保障计算软件特别是算法的可靠性在很大程度上决定了装备保障的效率乃至军事行动的成败。利用形式化软件工程的研究成果、特别是引入算法程序的形式化开发方法，对我军通用装备保障领域中的大量算法类问题进行有效求解，有利于优化保障结构、统筹保障资源、整合保障力量、提高保障时效，促进装备整体战斗力水平的提升。 本文以高可信软件开发方法PAR为基础，面向装备保障计算的领域需求，提出了一类离散最优化问题（discrete optimization problem, DOP）的结构模型和算法推演技术，并成功推演了一系列典型的装备保障算法。本论文的主要创新性贡献如下： （1）定义了DOP的结构模型，提出了基于单点结构（Singleton）的问题分划递推策略，进而通过PAR算法推演生成问题的高效求解算法，涵盖了多种传统算法设计策略，显著提高了算法程序设计的机械化水平。 （2）提出了描述DOP分划递推过程的问题简约图（problem reduction graph, PRG）模型，并针对典型DOP结构推演得到了一组PRG构造算法模式，其中每个算法模式都涵盖了满足特定代数结构性质的一大类具体问题。 （3）阐述了PAR算法推演的范畴模型，为算法设计和重用提供了抽象而有效的方法指导。 （4）对我军通用装备保障领域具有代表性的48个问题进行了形式化的算法推演，构建了领域算法库。 （5）在PAR平台的基础上设计了装备保障算法开发平台的原型COPALM，支持DOP算法推演和重用，进而提高了相关应用软件的开发效率。

智能玻璃建筑节能特性分析

智能玻璃能够根据人的意愿或者外界环境的变化动态的调节太阳光的输入，是新一代的建筑节能玻璃，目前引起广泛的关注。本文选取了两种典型的智能玻璃——电致变色玻璃和VO2热色玻璃，采用动态能耗分析软件EnergyPlus分别对其建筑节能特性进行了分析，具体研究内容如下： （1）讨论了电致变色玻璃不同控制方式对其节能效果的影响。结果表明，电致变色玻璃选用合适的控制方式可以显著降低建筑的能耗，但如果控制方式选用不当，采用电致变色玻璃后建筑的能耗反而会高于采用普通白玻的能耗。此外，无论在何种控制方式下，采用电致变色/LOW-E的节能效果都要优于电致变色/白玻中空玻璃。 （2）对VO2光学薄膜的膜系结构进行了优化，研究了外观颜色与膜层厚度的关系，设计出的TiO2(135nm)/VO2(50nm)/ITO(45nm)/glass三层膜结构相对于VO2(50nm)/glass的单层膜结构，太阳能调节量提高了从3.7%提高到9.8%，半导体状态时的可见光透过率从33.6%提高到55.5%，金属状态时的可见光透过率从34.0%提高到50.0%，同时半导体与金属状态时的膜面发射率都有很大程度的降低。 （3）研究了VO2热色玻璃的热学性能和建筑节能特性，重点分析了膜层结构、膜面位置、建筑的地理位置等因素对VO2热色玻璃建筑节能效果的影响。结果表明，对于单层VO2热色玻璃，其功能膜面朝向室内比朝向室外可以获得更好的节能效果，而对于由VO2热色玻璃与白玻组成的双层玻璃，其功能膜面位于室内玻璃的外侧时VO2很难起到相应的调节作用。另外，与其他类型的玻璃相比，虽然一定膜层结构下VO2热色玻璃在不同地区的建筑能耗低于白玻，但是在全年以采暖为主的严寒地区和全年以空调为主的夏热冬暖地区，VO2热色玻璃的节能效果分别不及高透型和遮阳型LOW-E玻璃。

Kinetics of picosecond laser pulse induced charge separation and proton transfer in bacteriorhodopsin

Bacteriorhodopsin (BR) films oriented by an electrophoretic method are deposited on a transparent conductive ITO glass. A counterelectrode of copper and gelose gel is used to compose a sandwich-type photodetector with the structure of ITO/BR film/gelose gel/Cu. A single 30-ps laser pulse and a mode-locked pulse train are respectively used to excite the BR photodetector. The ultrafast failing edge and the bipolar response signal are measured by the digital oscilloscope under seven different time ranges. Marquardt nonlinear least squares fitting is used to fit all the experimental data and a good fitting equation is found to describe the kinetic process of the photoelectric signal. Data fitting resolves six exponential components that can be assigned to a seven-step BR photocycle model: BR-->K-->KL-->L-->M-->N-->O-->BR. Comparing tests of the BR photodetector with a 100-ps Si PIN photodiode demonstrates that this type of BIR photocletector has at least 100-ps response time and can also serve as a fast photoelectric switch. (C) 2003 Society of Photo-Optical Instrumentation Engineers.

毛细管电泳电化学发光的药物及生物分析研究

本论文主要研究了毛细管电泳电化学发光分离检测技术在药物及生物分析中的应用，包括以下五个方面的内容： 1. 利用毛细管电泳电化学发光连用技术分离检测临床药物丙吡胺，详细考察了影响分离和检测的各种因素，在优化的实验条件下，此方法的检测限达到2.5×10-8 mol L-1 (S/N = 3)，优于已报导的各种检测方法。该方法简单快速、高效灵敏。采取一种简单易行的液液萃取预处理，可成功用于实际加标尿样的分析。2. 发展了手性毛细管电泳电化学发光连用技术，成功实现了实际加标血浆中外消旋丙吡胺药物的手性分离。该工作首次将毛细管电泳手性分离与电化学发光检测结合起来，有一定的创新意义。与传统手性分离模式不同的是，该“非传统”手性分离模式中的毛细管进样端和出口端的缓冲溶液在种类、组成、离子强度及pH值等参数上均存在差异，不仅达到了理想的分离效果，同时实现了高灵敏的检测。3. 研究了毛细管电泳电化学发光连用技术中出现的诱导峰的成因，考察了影响诱导峰峰强度和峰位置的各种因素，提出了一种合理的机理进行成因解释。诱导峰的出现不是由于化学络合作用，而是分离缓冲溶液和注入的样品中的某些组分在动态电泳过程中所发生的物理作用导致的。4. 合成了钌配合物的电化学发光探针，基于亲和素修饰电极和蛋白质的电化学发光标记和生物素化的双重标记，实现了蛋白质的定量检测。利用碳纳米管对蛋白质强的吸附作用以及在缩合试剂存在的条件下羧酸功能化的碳纳米管可与蛋白质共价键和的双重特点，使亲和素固定到玻碳电极上；经生物素化和电化学发光探针双重标记的蛋白质分子（BSA）通过亲和素-生物素特异性相互作用结合到电极表面，在TPA存在的条件下并施加合适的扫描电位，所得到的ECL强度与蛋白质浓度在一定范围内成线性关系，从而实现蛋白质的定量测定。此普适性的方法也可成功用于溶菌酶的定量检测。5. 基于适配子的“三明治”模式和DNA的电化学发光标记，发展了一种新型的电化学发光适配子传感器，结合金纳米放大效应和巧妙的自组装过程设计，实现了凝血酶的灵敏、经济实效的检测。首先，金纳米溶胶标记的捕获适配子1固定到ITO电极上，结合上目标分子凝血酶后，另一种标记有电化学发光探针的探针适配子2也与凝血酶产生强的特异性相互作用，从而结合到电极表面上。在给定的条件下，所得ECL信号与目标分子凝血酶浓度相关，进行ECL检测，所得到的信号-浓度曲线很好地满足“三明治”反应模式的特点，检测限约为10nM。特异性考察说明此电化学发光适配子传感器对于alfa-凝血酶有着极好的选择性，而对bata，gamma-凝血酶基本无响应。