Mn^(2+)掺杂CdS量子点敏化太阳电池的性能北大核心

采用连续式离子层吸附与反应(SILAR)法不仅成功制备出CdS量子点敏化的TiO2纳米晶光阳极,而且实现了Mn2+在CdS量子点晶格内部的可控掺杂。应用场发射扫描电子显微镜(FESEM)对电极的形貌进行了分析和表征。继而通过组装光伏电池研究Mn2+掺杂浓度与电池性能之间的关系。通过测量其紫外-可见吸收光谱及电流密度-电压(J-V)特性曲线考察电池性能随Mn2+掺杂量的变化规律。在研究中发现,掺杂适量的Mn2+有助于提高CdS/TiO2光阳极对可见光的吸收,进而增强太阳电池的能量转换效率。当Mn2+浓度为0.075 mmol/L时,量子点敏化太阳电池(QDSSC)的能量转换效率可达2.85%,较未掺杂的光阳极试样性能提高约50%。     

CdSe@CdTe核壳II型量子点掺杂的薄膜太阳能电池

采用胶体化学法制备了CdSe@CdTe核壳量子点,将其置于CdTe量子点层与CdSe量子点层间构筑了三层结构的全无机薄膜太阳能电池(ITO/CdTe/CdSe@CdTe/CdSe/Al),在电池制备过程中对量子点薄膜进行了退火处理。吸收光谱、荧光光谱及荧光寿命测试结果表明所制备的CdSe@CdTe量子点为典型的II型量子点。其光电转换性能测量结果表明所制太阳能电池具有高达0.48%的能量转换效率,这主要得益于三层量子点间能带能量的差异对电子与空穴的定向传输的促进以及退火工艺对薄膜结晶质量的改善。     

三元合金CdSexTe1-x量子点敏化太阳能电池

为了获得高光电转化效率的量子点敏化太阳能电池,我们制备了水相合金量子点CdSexTe1-x,通过直接吸附方法组装了量子点敏化太阳能电池,比较不同Se:Te比例下CdSexTe1-x电池的性能变化;当Se:Te=2:3时,CdSexTe1-x敏化太阳能电池各种性能最佳,其光电转换效率可达2.47%。相比于同条件制备的水相CdSe和CdTe量子点敏化太阳能电池转换效率分别提升了90% 和70%。进一步改善CdSexTe1-x量子点表面修饰,抑制电池暗电流,在使用液态多硫电解液的环境下,获得了填充因子为72.7%的CdSexTe1-x量子点敏化电池。     

非晶硅薄膜光伏电池结构参数分析

考虑到nip型[ITO/a-Si(n)/a-Si(i)/a-Si(p)/Al]非晶硅光伏电池的各膜层厚度、掺杂浓度等因素,对非晶硅光伏电池的转换效率、填充因子、开路电压等性能参数进行了数值分析与讨论。结果表明,随p型层厚度的增加,光伏电池的短路电流密度、转换效率、开路电压值都有所增加。当本征层的厚度增加时,短波段内的光谱响应变差、内量子效率下降。当n型层厚度为5 nm,本征层厚度为5 nm,p型层厚度为10μm,受主掺杂浓度为2.5×1019cm-3,施主掺杂浓度为1.5×1016cm-3时,转换效率可达9.728%。     

适度加快我国薄膜电池产业发展步伐

<正>薄膜太阳能电池生产线的增加是2008年太阳能电池产业的一个显著特点。薄膜太阳能电池虽然早已出现,但由于光电转换效率低、衰减率较高等问题,前些年未引起业界的足够关注,市场占有率很低。随着其技术的不断进步,光电转换效率得到迅速提高,现在比2年以前约提升了30%～40%,虽然     

物理冶金多晶硅太阳电池叠层钝化减反射结构模拟

采用PC1D模拟软件对p型物理冶金多晶硅太阳电池的SiO2/Si Nx/SiNx叠层钝化减反射结构进行了计算模拟。结果表明:在SiNx/Si Nx双层减反射结构中引入SiO2钝化层后可以明显改善电池的外量子效率与表面减反射效果,并最终提高电池转换效率;随着SiO2膜厚度的增加,电池表面反射率呈先降低后增加的趋势,而电池外量子效率及转换效率则呈现出相反的趋势。二氧化硅膜厚度在2~8 nm时,电池转换效率变化不大,并在6 nm时效率达到最大值18.04%,当二氧化硅膜厚度大于8 nm后电池转换效率会出现明显下降。     

微型逆变器提升太阳能系统整体效能,提高输出功率

传统的太阳能电池存在结构性缺陷,导致系统无法充分发挥其性能,加上系统使用时间越长效率就越低等缺点,阻碍了它的发展,而逆变器可以帮助解决这一问题,提升太阳能系统的整体性能。近年来,太阳能电池制造商持续致力于开发高效能产品,但就2010年2月的标准结晶硅太阳能电池的最高光电转换效率来看,面积156×156mm2、厚度为200μm的太阳能电池也只能达到19.3%的转换效率。由于太阳能电池模块的光电转换效率并不高,因此要想从太阳能电     

金属表面等离激元增强聚合物太阳电池

研究了Au纳米颗粒表面等离激元增强聚噻吩(P3HT)与富勒烯衍生物(PCBM)共混体系聚合物太阳电池的光电转换效率。Au纳米颗粒表面由双十烷基二甲基溴化铵(DDAB)修饰,能够均匀分散在活性层中。研究了Au纳米颗粒的质量分数对电池性能的影响,发现质量分数为1.2%时,电池性能最佳,转换效率高达3.76%,较未掺杂的参比电池相对提高约20%。掺入Au纳米颗粒后P3HT和PCBM共混膜光吸收显著增强,从而使电池外量子效率大大增加。电池效率的提升主要归结于Au纳米颗粒表面等离激元激发所引起的近场增强。     

友达光电开始量产太阳能电池模块

中国台湾地区友达光电（AUO）在“PV EXPO2010第三届国际太阳能电池展”上展出了2009年底已经开始量产的转换效率为13．2％的多晶硅太阳能电池模块，最大输出功率为220W。此外，该公司还正在开发转换效率为14．66％的多晶硅太阳能电池模块和转换效率为14．7～15．05％的单晶硅太阳能电池模块。     

溅射功率对染料敏化TiO2电极光电性质的影响

用直流磁控溅射法在不同溅射功率下沉积了TiO2薄膜,并制备了染料敏化太阳能电池。I-V曲线的结果表明,150～200W,随着溅射功率的升高,电池的短路光电流和光电转换效率增大,200W时制备的TiO2电极的光电转换效率较175W时的提高了75%,225W时短路光电流和转换效率均有所下降;从喇曼光谱、透射光谱等的表征可知,200W时沉积的TiO2薄膜开始形成锐钛矿结构,并且其厚度比225W时沉积的薄膜更大。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.