Room temperature direct-bandgap electroluminescence from a horizontal Ge ridge waveguide on Si

We report a lateral Ge-on-Si ridge waveguide light emitting diode(LED) grown by ultrahigh vacuum chemical vapor deposition(UHV-CVD). Direct-bandgap electroluminescence(EL) of Ge waveguide under continuous current is observed at room temperature. The heat-enhancing luminescence and thermal radiation-induced superlinear increase of edge output optical power are found. The spontaneous emission and thermal radiation based on the generalized Planck radiation law are calculated and fit very well to the experimental results. The Ge waveguides with different lengths are studied and the shorter one shows stronger EL intensity.     

联萘酚衍生物的光电功能及其应用*

联萘酚及其衍生物具有C₂轴不对称性、修饰位点多、手性构型高度稳定等特点,在分子或离子识别、有机电致发光（OLED）、非线性光学以及分子机器等光电功能材料领域得到了广泛研究并展现出良好的应用前景。本文依据联萘酚衍生物光电功能材料分子结构的不同,总结了其结构修饰的设计原理、修饰方法及其应用,评述了各位点修饰材料的结构和光电性能的关系：单位点及多位点修饰的联萘酚,主要是通过氢键作用、光诱导电子转移（PET）等机理实现分子或离子识别,多应用于荧光化学传感器;双位点修饰的联萘酚,主要是利用扭转非平面结构和π共轭特性等调节光电性能,广泛应用于OLED;同样,基于C₂轴不对称性和手性诱导特性,联萘酚衍生物在非线性光学以及分子机器等领域也展现出良好的应用。最后,展望了联萘酚类光电功能材料的研究和发展方向。     

8-羟基喹啉合镁作为发光层的明亮电致发光器件

以氯化镁与8 羟基喹啉反应合成了8 羟基喹啉合镁配合物,用元素分析、热重分析和红外吸收光谱分析确定了其组成为Mg(C9H7NO)2·2H2O。结果表明,该配合物是热稳定性高、升华性好、光致发光性能优良的蓝绿色发光材料;以该配合物作为发光层和电子传输层,用真空镀膜法得到了结构为ITO/TPD/Mgq2/Al的明亮的蓝 绿色电致发光器件。     

Structural,photophysical, and electrophosphorescent properties of platinum(II) complexes supported by tetradentate N2O2 chelates

We present an examination of the structural and photophysical characteristics of [Pt(N(2)O(2))] complexes bearing bis(phenoxy)diimine auxiliaries (diimine=4,7-Ph(2)phen (1) and 4,4'-tBu(2)bpy (2)) that are tetradentate relatives of the quinolinolato (q) ligand. These neutral derivatives display high thermal stability (>400 degrees C in N(2)). While the crystal lattice in 1 consists of (head-to-tail)-interacting dimers, molecules of 2 are arranged into infinitely stacked planar sheets with possible pi-pi interactions but no close Pt.Pt contacts. Complexes 1 and 2 exhibit moderately intense low-energy UV/Vis absorptions around lambda=400-500 nm that undergo negative solvatochromic shifts. Both derivatives are highly luminescent in solution at 298 K with emission lifetimes in the micros range, and mixed (3)[l-->pi*(diimine)] (l=lone pair/phenoxide) and (3)[Pt(d)-->pi*(diimine)] charge-transfer states are tentatively assigned. The excited-state properties of 2 are also investigated by time-resolved absorption spectroscopy and by quenching experiments with pyridinium acceptors to estimate the excited-state redox potential. These emitters have been employed as electrophosphorescent dopants in multilayer OLEDs. Differences between the brightness, color, and overall performance of devices incorporating 1 and 2 are attributed to the influence of the diimine substituents.     

用C60为空穴缓冲层的高效率有机电致发光器件

以富勒烯C60作为空穴注入缓冲层，在结构为ITO／C60／TPD／Alq3/LiF/Al的器件中，改善了器件的发光效率。研究了C60厚度对器件发光特性的影响。当C60厚度为1.6nm时，器件发光效率最高。在电流密度为100mA/cm^2时，该器件的效率比没有缓冲层的器件提高近一倍。     

Room temperature electroluminescence of nanofabricated Si–Si1−xGexquantum dot diodes

The fabrication and room temperature light emission of a series of 50 nm Si–SiGe quantum dot diodes emitting light at about 1.3 μm are reported. These diodes are made from molecular beam epitaxially (MBE) grownp–i–nstructures with the active region being either a superlattice or a single heterolayer. It was found that the electrical-to-optical power conversion efficiency of the diodes was 0.14%. Possible light emission mechanisms and technological aspects of the work are discussed.     

基于ZnSe的有机-无机异质结电致发光器件

以电子束蒸发的方法制备硒化锌(ZnSe)薄膜，研究了基于ZnSe的有机-无机异质结电致发光器件.在双层器件ITO/ZnSe(50nm)/Alq₃(12nm)/Al中看到了峰值位于578nm的ZnSe电致发光，却很难得到单层器件ITO/ZnSe(50—120nm)/Al的电致发光；在此基础上进一步引入有机空穴传输层(HTL)，通过改变器件的结构，讨论了ZnSe对有机-无机异质结器件ITO/HTL/ZnSe/Alq₃/Al电致发光特性的影响.其电致发光光谱的研究结果证实了ZnSe在器件中的作用：ZnSe既起传输电子的作用，也起到传输空穴的作用，还作为发光层.并对ZnSe的发光机理进行了讨论. 关键词： 硒化锌 有机-无机异质结 电致发光 空穴传输层     

ZnS:Mn、Cu粉末直流电致发光器件直流和交流电致发光一致性的研究

本文研究了粉末直流电致发光(DCEL)器件在直流(DC)和交流(AC)电压下光电特性的关联和区别及其物理机制. 实验发现,在DC和AC条件下DCEL器件的阻抗特性之间没有任何有规律的关联,而AC条件下的激发电流I_A和亮度B_A以及DC条件下的亮度B_D和发光效率η_D四个参量之间则表现出某种程度的一致性,但AC条件下的发光效率η_A与上述四个参量之间却表现出某种相反和相对立的关系. DCEL器件的光电特性具有强烈非线性和对电压方向的非对称性.正半周(或DC条件下)DCEL器件是在高电场和低电流激发下的发光.对发光起主要作用的是电场强度.在负半周时则是低电场和大电流激发下的发光.对发光起主要作用的是激发电流而不是电场强度.在AC条件下依材料、工艺、形成条件和工作电压的不同,DCEL器件可能更多地显示出正半周,负半周或两半周综合的光电特性.上述观点可以解释本文的实验结果.     

有机稀土Eu（DBM）3bath配合物电致发光

有机稀土Ｅｕ（ＤＢＭ）３ｂａｔｈ配合物电致发光＊梁春军李文连＊＊洪自若彭俊彪ａ）虞家琪ａ）赵丹赵东旭（中国科学院长春物理研究所，长春１３００２１）ａ）（中国科学院激发态物理开放研究实验室，长春１３００２１）关键词有机电致发光，稀土配合物，窄带发射近几...     

Excitation and recombination processes during electroluminescence of rare earth-activated materials

Electroluminescence phenomena in rare earth doped materials are reviewed. The main emphasis is in the basic physics of EL processes, viz. direct and indirect excitation and nonradiative and radiative recombination of rare earth ions. The device structures, the recent material development, and the present state of art in AC operated thin fdm EL devices have been reviewed as well.