Hybrid Organic Light-Emitting Diodes with Low Color-Temperature and High Efficiency for Physiologically-Friendly Night Illumination

Low color-temperature (CT) light sources are preferred for physiologically-friendly illumination at night due to their low suppression of melatonin secretion. We fabricated low-CT hybrid organic light-emitting diodes (OLEDs) by constructing a double emissive-layer (EML) structure, with a blue-red fluorescent-phosphorescent hybrid EML and a green phosphorescent EML, separated by a bipolar interlayer. By doping a red phosphor in a blue fluorescent mixed-host with a decent concentration, blue and red emissions from the host and dopant, respectively, were obtained. The CT of the optimized device was tuned to less than 2500 K, with the brightness ranging from 100 to 10,000 cd m⁻². In addition, the low-CT OLED exhibited much higher efficacy than other low-CT light sources, such as incandescent bulbs and candles. The maximum power efficiency and external quantum efficiency of the hybrid OLED reached 54.6 lm W⁻¹ and 24.3 %, respectively, which only rolled off to 44.2 lm W⁻¹ and 23.6 % at 1000 cd m⁻², with a CT of 1910 K. Low-CT OLEDs with high efficacy provide a promising alternative for night lighting that will safeguard human health.     

Highlighting of two types of defects in 1300 nm PBC laser diodes

Laser diodes of PBC (p-substrate buried crescent) structure and emitting at 1300 nm, were subjected to calibrated electrostatic discharges (ESD). A failure analysis was then set up using a scanning optical microscope (SOM) and has allowed the localization of the damaged zones. The comparison of the results obtained with the electro-optical characteristics has highlighted two types of complementary defects: (i) a so-called optical type defect, since the optical power is significantly reduced, although leakage current has not occurred (active layer seriously damaged); (ii) a so-called electrical type defect, since the leakage current increases, although the optical power is barely reduced (active layer weakly damaged).     

基于共振隧穿二极管的集成电路研究

RTD基集成电路所具有的超高速、低功耗和自锁存的特性,使其在数字电路、混合信号电路以及光电子系统中有着重要的应用。首先对RTD与化合物半导体HEMT,HBT以及硅CMOS器件的集成工艺进行了介绍。在MOBILE电路及其改进和延伸的基础上,对高速ADC／DAC电路和低功耗的存储器电路进行了具体的分析。最后对RTD基电路面临的主要问题和挑战进行了讨论,提出基于硅基RTD与线性阈值门（LTG）逻辑相结合是未来纳米级超大规模集成电路的最佳发展方向。     

一种使用一维电磁带隙结构的高性能Ka频段四次谐波混频器

介绍了一种全集成微带四次谐波混频器,该混频器采用了一种新型电磁带隙结构,可获得很低的变频损耗指标.阐述了一般的谐波混频理论,并用谐波平衡软件对整个电路进行优化仿真.实测得到射频在34~36GHz的频带内,固定中频为100MHz,该混频器最小变频损耗7.67dB,最大变频损耗<10dB.     

隧道再生双有源区AlGaInP发光二极管提取效率的计算

建立了发光二极管提取效率的理论计算模型,分析了影响隧道再生双有源区AlGaInP发光二极管提取效率的主要因素,包括从出光表面出射的光、体内的光吸收损耗、衬底对光的吸收损耗、金属电极对光的吸收损耗,模拟计算了隧道再生双有源区AlGaInP发光二极管的提取效率,计算得到隧道再生双有源区AlGaInP LED管芯的上有源区和下有源区提取效率分别为5．24％和9．16％。     

基于PIN光电二极管的个人辐射探测器研制

为使公众能自行探测所处环境的辐射水平,本文利用PIN光电二极管直接测量X/γ射线的原理研制了便携式环境辐射探测系统,该系统采用智能终端控制探测设备。其中,探测模块中设计了弱信号放大电路,控制和通信模块的设计基于无线微控制器。该环境辐射探测器具有低成本、低功耗、体积小、易使用、易组网等特点。经国防科技工业电离辐射一级计量站检定,探测器各项指标均符合国家剂量仪鉴定规程JJG 521-2006的要求。     

SBD势垒高度的影响因素

针对硅材料的肖特基势垒二极管(Schottky Barrier Diode,简称SBD)的击穿电压普遍很低,严重影响其实际应用的问题,采用实验与理论分析相结合的方式,着重于表面态、界面层对势垒高度的影响进行研究.提取了三个重要参数:表面态密度D_i、界面层电容密度C_i和表面态中性能级Φ_0.结果表明,势垒高度的高低强烈依赖于这三个特性参数的大小.     

p-n复合半导体光催化剂研究进展

综述了p-n复合半导体光催化剂的光催化原理及研究现状。根据p-型材料种类,将p-n复合半导体光催化剂分为4类:p-型半导体材料为镍氧化物、p-型半导体材料为钴氧化物、p-型半导体材料铜氧化物及由其它p-型半导体材料组成的"p-n结型"、"二极管"式p-n复合半导体光催化剂,分别对其研究状况进行了介绍。提出了当前p-n复合半导体光催化剂研究中存在的一些问题,并对未来的研究方向进行了探讨。     

Polymer-based blue electrophosphorescent light-emitting diodes based on a new iridium(III) diazine complex

Polymer-based blue electrophosphorescent light-emitting diodes are reported by doping iridium(III) diazine complex (DFPPM)₂Ir(pic) (DFPPM = 2-(2,4-difluorophenyl)-pyrimidine, pic = picolinate) in poly(vinylcarbazole) (PVK) as the source of emission. The iridium(III) diazine complex shows sky blue emission with its maximum emission peak at 476 nm originating from an admixture of triplet metal-to-ligand charge-transfer and ligand-centered states. The (DFPPM)₂Ir(pic)-doped device furnishes a maximum external quantum efficiency of 2.2% and power efficiency of 1.9 lm/W at a 10 wt% doping concentration.     

Synthesis and near-infrared luminescent properties of some ruthenium complexes

A series of seven ruthenium complexes with different ligands were synthesized and their optical, electrochemical and photoluminescent properties were characterized. Electroluminescent properties of these complexes were further evaluated using a light-emitting electrochemical cell with a configuration of indium tin oxide (ITO)/complex (100 nm)/Au (100 nm). Tunable photoluminescence (PL) and electroluminescence (EL) from 630 to 1040 nm have been achieved by adjusting the LUMO and HOMO levels of ruthenium complexes.