Te薄膜封装层对有机电致发光器件寿命的影响

采用Te薄膜封装层作为OLED(organic light emitting diode)器件的保护层,以达到延长器件使用寿命的目的.在高真空(3×10-4Pa)条件下,利用真空蒸镀的方法,在绿光OLED多层器件各功能层蒸镀完成后,又在阴极的外面蒸镀了一层Te薄膜封装层,然后再按一般的方法进行封装.对比了一般封装与增加Te薄膜封装层后器件的性能,封装过程均未加干燥剂.研究发现,未加Te薄膜封装层器件的半衰期为2 880 h,增加Te薄膜封装层后器件的半衰期接近5 800 h.由此可见,Te薄膜封装层的增加将使器件的寿命延长两倍多.并且所增加的Te薄膜封装层基本不影响器件的电流-电压特性、亮度-电压特性、色坐标等光电性能.     

原子层沉积方法制备低温多层Al2O3/TiO2复合封装薄膜的研究

原子层沉积(ALD)方法可以制备出高质量薄膜,被认为是可应用于柔性有机电致发光器件(OLED)最有发展前景的薄膜封装技术之一。本文采用原子层沉积(ALD)技术,在低温(80℃)下,研究了Al₂O₃及TiO₂薄膜的生长规律,通过钙膜水汽透过率(WVTR)、薄膜接触角测试等手段,研究了不同堆叠结构的多层Al₂O₃/TiO₂复合封装薄膜的水汽阻隔特性,其中5 nm/5 nm×8 dyads(重复堆叠次数)的Al₂O₃/TiO₂叠层结构薄膜的WVTR达到2.1×10^-5 g/m²/day。采用优化后的Al₂O₃/TiO₂叠层结构薄膜对OLED器件进行封装,实验发现封装后的OLED器件在高温高湿条件下展现了较好的寿命特性。     

MgF2/Se薄膜封装层对OLED性能及寿命的影响

有机电致发光器件(OLEDs)在使用过程中,易受到 空气中水汽、氧气及其它污染物的影响从而导致其工作寿命降低。本文将具有良好光透过率 和热稳定性的MgF₂薄膜与在水汽和氧气中具有良好稳定性的Se薄膜通过真空蒸镀制成复 合薄膜作为OLEDs的封装层,以达到提高器件使用寿命的目的。器件各功能层蒸镀完成后, 保持真空度(3×10－4 Pa)不变,在阴极表面蒸镀MgF₂/Se薄 膜封装层。比较 了绿光OLED器件(器件结构为ITO/CuPc/NPB/Alq₃:C-545T/Alq ₃/LiF/Al)封装前后的亮度-电压-电流密度特性、电致发光光谱及寿命。研究 发现,经过MgF₂/Se封装后,器件的电流密度-电压特性、亮度和发光光谱几乎没 有受到影响,二者的光谱峰都在528 nm处,色坐标(CIE)分别为(0.3555,0.6131)和(0.3560,0.6104),只是起亮电压由3V变为4V;器件的寿命由原来的175h变为300h,提高了1.7倍 。因此,MgF₂/Se薄膜是一种有效的OLEDs无机薄膜封装层。     

Se薄膜封装层对OLED器件寿命的影响

对于绿光OLED多层器件,在高真空条件下,利用真空蒸镀的方法,在各功能层蒸镀完成后,又在阴极的外面蒸镀了一层硒薄膜封装层,然后再按一般方法进行封装.对比了正常封装与增加Se薄膜封装层后器件的性能,对比实验中封装过程都未加干燥剂.研究发现未加Se薄膜封装层器件的半衰期为2 880 h,增加Se薄膜封装层器件的半衰期接近4 000 h,Se薄膜封装层的增加将器件的寿命延长了1.4倍;研究还发现Se薄膜封装层基本不影响器件的电流-电压特性、色坐标等光电性能.     

柔性金属膜封装器件的水汽阻隔性能研究

通过UV树脂和柔性金属薄膜将干燥片和透气绝缘的聚二甲基硅氧烷(PDMS)膜封装在器件中, 利用钙(Ca)膜电学测试方法测定封装结构的水汽透过率 (WVTR),研究了该封装方法的水汽阻隔性能。实验结果表明, Ca膜蒸镀时的温度调控极大影响Ca膜均 匀性和表面形貌,从而影响器件的水汽透过率检测结果。本文提出的柔性金属封装方法具有 良好的水汽阻 隔性能,其WVTR在封装90h后仍达到5×10－4 g/m²/day 以下,水汽主要从器件周围的UV树脂渗透,与传统薄膜封装的水汽渗透机制有很大不同。     

透明叠层结构Ag/MoO_3/Ag阳极对绿光OLED器件性能的影响

本文采用一种结构为Ag/MoO_3/Ag的金属/氧化物/金属(M_1/O/M_2)叠层替代ITO作为OLED器件的阳极,研究Ag/MoO_3/Ag叠层结构变化对于OLED器件电极透过率、亮度、光谱等性能的影响。实验采用真空蒸镀方法制备了一系列器件,器件结构为Ag/MoO_3/Ag/MoO_3(10nm)/NPB(40nm)/Alq_3(60nm)/LiF(1nm)/Al(150nm)。对比器件的电压-电流密度、电压-亮度、光谱特性等数据,表明Ag/MoO_3/Ag的结构为20/20/10(nm)时,器件性能较好。在驱动电压为11V时,其亮度达到18 421cd/m~2,电流效率为2.45cd/A;且因器件中存在微腔效应,其EL光谱蓝移,半高宽变窄。但考虑到530nm处其电极透过率仅为17%,所以经换算该器件实际发光亮度比ITO电极器件更高。该Ag/MoO_3/Ag叠层阳极制作相对简单,经优化后在顶发射和柔性OLED器件方面将具有一定的应用前景。     

有机/无机/有机结构的封装薄膜水汽透过率研究

为了减少原子层沉积(ALD)方法在氧化物薄膜制备过程中ALD反应气对有机电致发光器件(OLED)性能的影响,利用旋涂光交联聚合物技术,直接在OLED上形成有机/无机/有机3层结构的保护薄膜。通过扫描电子显微镜(SEM)、原子力显微镜(AFM)的表面形貌分析表明,3层结构的封装薄膜表面平滑且致密,减少水(H2O)汽在氧化物表面积聚,降低H2O对氧化物薄膜的腐蚀作用,且成膜过程对OLED的各功能层没有伤害。经Ca薄膜的电学方法测量证明,这种3层结构的封装薄膜对气体有极高的阻隔作用,其H2O汽透过率(WVTR)可以达到9.0×10-5 g/(m2·day),从而实现了对OLED的有效保护。     

有机电致发光器件(OLED)的封装技术研究

有机电致发光显示器(OLED)对水汽和氧气非常敏感,渗入OLED器件内的水汽和氧气会和有机功能层及电极材料发生反应而影响器件寿命。为此,文中根据OLED器件对封装材料的要求,分析了OLED器件封装技术,重点介绍了薄膜封装技术的研究现状。     

高亮度微腔有机电致发光器件

为了实现有机电致发光器件(OLED)发射光谱的窄化和高亮度,真空热蒸镀具有不同微腔结构的OLED(MOLED):玻璃衬底/分布式布拉格反射器(DBR)(1～4对的SiO2/Ta2O5层)/ITO/空穴传输层(HTL,α-NPD)/发光层(EML,Alq3:Rubrene或Alq3:Coumarin6)/电子传输层(ERL,Alq3)LiF/Mg/Ag,其中沉积DBR结构采用电子束沉积法。实验表明:该MOLED的发射光谱半波长宽度(FWHM)随DBR层数的增加而减小至最小值10nm;并且在2层DBR时,掺杂Rubrene器件得到更大的电流效率,约20cd/A,最大亮度为2.6×105cd/m2。研究发现,蓝光MOLED能够对自发光产生吸收现象,降低了出光效率。     

利用有机覆盖层提高OLED出光效率

将Alq作为覆盖层真空蒸镀到玻璃基板后制作底发射有机电致发光器件(OLED),所制备的器件结构为:Glass/Alq(xnm)/Al(15nm)/MoO3(30nm)/NPB(60nm)/Alq(65nm)/LiF(1nm)/Al(150nm)。通过研究器件光辐射特性曲线,可以看出覆盖层厚度的变化引起光的干涉效应的变化是导致电致发光变化的原因,广角干涉和多光束干涉之间的相互作用可以通过覆盖层的厚度来调节,并且半透明的Al膜做阳极,将覆盖层蒸镀到阳极之外玻璃基板上,半透明的铝膜和覆盖层与阴极组成微腔器件,通过改变覆盖层的厚度调节微腔的腔长,使OLED电致发光光谱的中心波长发生红移。     

Interfacial reaction and shear strength of SnAgCu-xNi/Ni solder joints during aging at 150 °C

The interfacial microstructure and shear strength of Sn3.8Ag0.7Cu-xNi (SAC-xNi, x = 0.5, 1, and 2) composite solders on Ni/Au finished Cu pads were investigated in detail after aging at 150 °C for up to 1000 h. The interfacial characteristics of composite solder joints were affected significantly by the weight percentages of added Ni micro-particles and aging time. After aging for 200 h, the solder joints of SAC, SAC-0.5Ni and -1Ni presented duplex intermetallic compound (IMC) layers regardless of the initial interfacial structure on as-reflowed joints, whose upper and lower IMC layers were comprised of (CuNi)₆Sn₅ and (NiCu)₃Sn₄, respectively. Only a single (NiCu)₃Sn₄ IMC layer was ever observed at the SAC-2Ni/Ni interface on whole aging process. Based on the compositional analysis, the amount of Ni within the IMC regions increased as the proportion of Ni addition increased. The IMC (NiCu)₃Sn₄ layer thickness on the interface of SAC and SAC-0.5Ni grew more slowly when compared to that of SAC-1Ni and -2Ni, while for the (CuNi)₆Sn₅ layer the reverse is true. Except the IMCs sizes are increased with increased aging time, the interfacial IMCs tended to transfer their morphologies to polyhedra. In all composite joints testing, the shear strengths were approximately equal to non-composite joints. The fracturing observed during shear testing of composite joints occurred in the bulk solder, indicating that the SAC-xNi/Ni solder joints had a desirable joint reliability.     

有机发光二极管中ADN掺杂ErQ的1.54μm电致发光

自行设计了基于8-羟基喹啉铒(ErQ)为发射层(EMLs)和二硝酰胺铵(ADN)为蓝光主体材料的近红外有机发光二级管.器件的基本结构为(p-Si/NPB/EML/Bphen/Bphen:Cs2CO3/Sm/Au),设计并比较了三套不同发射层结构(ErQ/ADN为双层结构器件,(ErQ/ADN)×3为多层结构器件,ErQ:ADN为掺杂结构器件)的器件.三组器件在一定的偏压下,均可发出1.54μm的光,对应三价铒离子4I13/2→4I15/2的跃迁.其中,ADN:ErQ(1∶1)掺杂结构的近红外电致发光强度是ADN/ErQ双层结构中的三倍.此外,不同掺杂浓度的ADN:ErQ复合膜做了以下表征:吸收谱、光致发光谱和荧光寿命谱.实验结果证实了在近红外电致发光过程中存在从ADN主体分子到ErQ发射分子的高效率的能量转移.     

Emerging interconnects: a state-of-the-art review and emerging solutions

Aluminium was a primary material for interconnection in integrated circuits (ICs) since their inception. Later, copper was introduced as interconnect material which has better metallic conductivity and resistance to electromigration. As the aggressive technology scaling continues, the copper resistivity increased because of size effects, which causes increase in delay, power dissipation and electromigration. The need to reduce the resistor-capacitor??????? delay, dynamic power utilisation and the crosstalk commotion is as of now the fundamental main impetus behind the presentation of new materials. The purpose of this paper is to do a survey of interconnect material used in IC from introduction of ICs to till date. This paper studies and reviews new materials available for interconnect application which are optical interconnects, carbon nanotube (CNT), graphene nanoribbons (GNRs) and silicon nanowires which are alternatives to copper. While doing a survey of interconnect material, it is found that multiwalled CNTs, multilayer GNR and mixed CNT bundles are promising candidates and are ultimate choice that can strongly address the problems faced by copper but on integration basis copper would last for coming years.     

钠离子对poly(dT).poly(dA).poly(dT)三螺旋DNA分子呼吸模式的影响

利用分子结构的螺旋对称性,建立了一个包括钠离子的三链DNA分子poly(dT)*poly(dA)*poly(dT)的晶格动力学模型,计算了poly(dT)*poly(dA)*poly(dT)的氢键呼吸模式.结果发现钠离子的加入明显地淬灭了位于较低频率的几个最为强烈的Hoogensteen氢键呼吸模式,而对Watson-Crick氢键呼吸模式影响不明显,这说明钠离子能提高poly(dT)*poly(dA)*poly(dT)三螺旋结构的稳定性.该计算结果很好地解释了poly(dT)*poly(dA)*poly(dT)的热融化实验.     

聚对苯撑苯并双(口恶)唑发光及其器件制备

采用光谱技术,研究了聚对苯撑苯并双(口恶)唑(PBO)溶液的光敏发光特性,并用相对法估算出溶液发光效率在50%范围.结合光谱技术、半导体电学和电化学等研究手段,具体研究了以PBO为发光层的单层电致发光器件,研究结果显示,电致发光与薄膜的光致发光有具有相同的发光中心,峰值位于510 nm左右.同时发现,由于存制备过程中不同处理条件使得不同厚度薄膜残留的掺杂物质浓度不同,从而引起薄膜的导电性的不同.使得器件的阈值场强随PBO厚度的减小而逐渐增加.     

人小肠粘膜免疫酶的定位研究—光镜和电镜免疫组织化学染色法

本文对免疫酶组织化学的样品制备程序和染色方法做了详细的阐述。用直接法、间接法和ABC法,对人小肠免疫酶的定位,进行了光镜和电镜的观察,染色阳性反应显著,获得了满意的效果。并对染色技巧做了分析和探讨。     

BNBST无铅压电陶瓷的制备工艺研究

设计了（Bi0.55Na0.5）1-X（BaaSrb）xTiO3（BNBST[100x-100a／100b]）无铅压电陶瓷新体系。该体系压电陶瓷具有工艺特性及压电响应好，压电常数高的特点，且有实际应用前景的新型压电陶瓷材料体系。采用传统的陶瓷工艺制备了（Bi0.55Na0.5）1-X（BaaSrb）xTiO3无铅压电陶瓷，研究了制备工艺参数对其物化结构性能的影响。生料的热重-差热（TGA-DTA）分析表明，粉料合成过程中，先是SrTiO3、BaTiO3的形成，然后是（Bi0．5Na0．5）Tio，的形成，同时三者形成固溶体；密度测试表明，陶瓷的体积密度随烧结温度的升高而增大，可较易获得理论密度94％的陶瓷；X-射线能谱分析（EDAX）研究表明，陶瓷的Bi、Na的挥发随着烧结温度的升高而加剧。研究结果表明，要制备性能优良的无铅压电陶瓷，需要精确控制制备工艺。     

Arsenic deposition as a precursor layer on silicon (211) and (311) surfaces

We investigate the properties of arsenic (As) covered Si(211) and Si(311) surfaces by analyzing data from x-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED) images. We then create a model using total surface energy calculations. It was found that both Si(211) and Si(311) had 0.68±0.08 surface As coverage. Si(211) had 0.28±0.04 Te coverage and Si(311) had 0.24±0.04 Te coverage. The Si(211) surface replaces the terrace and trench Si atoms with As for a lower surface energy, while the Si edge atoms form dimers. The Si(311) surface replaces all terrace atoms and adsorbs an As dimer every other edge site. These configurations imply an improvement in the mean migration path from the bare silicon surface by allowing the impinging atoms for the next epitaxial layer, tellurium (Te), to bind at every other pair of edge atoms, and not the step terrace sites. This would ensure a nonpolar, B-face growth.     

Joint estimation of TOA and DOA in IR-UWB system using a successive propagator method

Impulse radio ultra-wideband (IR-UWB) ranging and positioning require accurate estimation of time-of-arrival (TOA) and direction-of-arrival (DOA). With receiver of two antennas, both of the TOA and DOA parameters can be estimated via two-dimensional (2D) propagator method (PM), in which the 2D spectral peak searching, however, renders much higher computational complexity. This paper proposes a successive PM algorithm for joint TOA and DOA estimation in IR-UWB system to avoid 2D spectral peak searching. The proposed algorithm firstly gets the initial TOA estimates in the two antennas from the propagation matrix, then utilises successively one-dimensional (1D) local searches to achieve the estimation of TOAs in the two antennas, and finally obtains the DOA estimates via the difference in the TOAs between the two antennas. The proposed algorithm, which only requires 1D local searches, can avoid the high computational cost in 2D-PM algorithm. Furthermore, the proposed algorithm can obtain automatically paired parameters and has better joint TOA and DOA estimation performance than conventional PM algorithm, estimation of signal parameters via rotational invariance techniques algorithm and matrix pencil algorithm. Meanwhile, it has very close parameter estimation to that of 2D-PM algorithm. We have also derived the mean square error of TOA and DOA estimation of the proposed algorithm and the Cramer-Rao bound of TOA and DOA estimation in this paper. The simulation results verify the usefulness of the proposed algorithm.     

系统级封装新型埋入式电源滤波结构的研究

在高密度小尺寸的系统级封装(SiP)中,对供电系统的完整性要求越来越高,多芯片共用一个电源网路所产生的电压抖动除了会影响到芯片的正常工作,还会通过供电网路干扰到临近电路和其他敏感电路,导致芯片误动作,以及信号完整性和其他电磁干扰问题.这种电压抖动所占频带相当宽,几百MHz到几个GHz的中频电源噪声普通方法很难去除.结合埋入式电容和电源分割方法的特点,提出一种新型高性能埋入式电源低通滤波结构直接替代电源/地平面.研究表明,在0.65～4GHz的频带内隔离深度可达-40～75 dB,电源阻抗均在0.25ohm以下,实现了宽频高隔离度的高性能滤波作用.分别用电磁场和广义传输线两种仿真器模拟,高频等效电路模型分析这种低通滤波器的工作原理以及结构对隔离性能的影响,并进行了实验验证.