Strategies to Improve Field Emission Performance of Nanostructural ZnO

Nanostructural ZnO is a good candidate for field emission (FE) because of its high aspect ratio, controllable electrical conductivity, and good thermal and chemical stability. In order to improve the FE performance, ZnO nanopins, gallium-doped nanofibers, periodic nanorod arrays, and aligned nanotubes were designed and fabricated by a vapor-phase transport method using ZnO + C and ZnO + C + Ga₂O₃ powder mixtures, electrochemical deposition, and hydrothermal decomposition, respectively. The FE behaviors including threshold of electric field, emission current density, field enhancement factor, and stability are reviewed in this paper based on our previous works. Some strategies to improve the performance of the nanostructural ZnO field emitters are demonstrated.     

有限空间液态场中声发射信号时延估计方法

石油储罐罐底腐蚀的定位可利用声发射信号的时延估计实现,但在有限空间液态场中信号的传播会产生严重的多途效应,对准确进行时延估计产生不利影响.提出一种基于信号截取的广义互相关时延估计方法.采用曲线拟合法对每路传感器采集信号进行波达时刻估计,然后进行信号截取,对两路传感器截取信号进行基于相位变换的广义互相关,实现信号的时延估计.实验结果表明,该方法能有效克服多途干扰,提高时延估计性能.     

Triphenylamine-based trinuclear Pt(II) complexes for solution-processed OLEDs displaying efficient pure yellow and red emissions

Highly efficient phosphors are critical in solution-processed organic light-emitting devices (OLEDs). Multinuclear Ir(III) complexes containing more than one metal center have showed great potential in fabricating high performance OLEDs, yet the electroluminescent (EL) properties of multinuclear Pt(II) complexes are rarely studied. In this work, two neutral trinuclear Pt(II) complexes are synthesized based on the triphenylamine core bearing three bidentate ligand arms. Both the yellow emitter (PyTPt) and deep-red emitter (IqTPt) exhibit improved photoluminescent quantum yields (PLQYs) compared with their corresponding mononuclear Pt(II) complexes. Furthermore, the PLQYs of PyTPt and IqTPt doped films are increased to 0.63 and 0.47, respectively. The solution-processed pure yellow-emitting device based on PyTPt achieves impressively high external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 16.92%, 56.74 cd/A and 29.09 lm W⁻¹, respectively, which are among the best performance reported for the OLEDs employing multinuclear Pt(II) complexes. The solution-processed device based on IqTPt shows pure red emission with the peak EQE approaching 9.0%. Both PyTPt and IqTPt display much higher EL efficiencies than their corresponding mononuclear Pt(II) complexes. This work demonstrates that it is an attritive strategy to develop multinuclear Pt(II) complexes for high-performance OLEDs.     

航天设备电磁兼容测试要求探讨

相对于飞机、舰船、车辆而言,航天器一旦进入太空,基本上不可维修,且航天器通常投资巨大,使得航天器的EMC 性能要求更为严格和苛刻,必须保证航天器在其整个寿命周期内不能出现任何影响其性能、任务和安全的电磁干扰问题,进而要求航天器的地面EMC 试验必须充分而有效。在制定航天器设备级EMC 试验要求时,必须保证各类设备具有足够的电磁干扰安全裕度,并进行充分的试验验证,从而需要以此为出发点,选取适用的试验项目,制定针对性的试验要求。     

Solution-processed aqueous composite hole injection layer of PEDOT:PSS+MoOx for efficient ultraviolet organic light-emitting diode

Hole injection layer (HIL) plays a crucial role in governing external quantum efficiency (EQE) of ultraviolet organic light-emitting diodes (UV OLEDs). We develop a solution-processed aqueous composite HIL of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) incorporated MoO_x (PEDOT:PSS+MoO_x) and cast successful application to UV OLEDs. PEDOT:PSS+MoO_x is characterized in detail with scanning electron microscopy, atomic force microscopy, UV–visible absorption spectra, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy and impedance spectroscopy measurements. The results show that PEDOT:PSS+MoO_x features superior film morphology and exceptional electronic properties such as enhanced surface work function and promoted hole injection capacity. With PEDOT:PSS+MoO_x as HIL, the UV OLED gives maximum EQE of 4.4% and radiance of 12.2 mW/cm² as well as improved durability. The electroluminescence peaks at 376 nm with full width at half maximum of 34 nm and stable voltage-dependent spectra. Our results pave a way for exploring efficient UV OLEDs with solution-processable techniques.     

Highly polarized luminescence from an AIEE-active luminescent liquid crystalline film

Luminescent liquid crystals (LLCs) have attracted significant interest for organic optoelectronic applications, especially for the generation of linear polarized light. Here, a novel LLC molecule, 2-(4-(nonanealkoxy)phenyl)-3-(4-formamidephenyl)-acrylonitrile (CN-NPFA), is reported, which shows strong fluorescence in the solid state due to the aggregation-induced enhanced emission (AIEE) effect. Moreover, a well-aligned liquid crystalline film using AIEE-active molecules, is obtained using an in-plane electric field with an alignment layer. It exhibits highly polarized luminescence (ρ = 0.74) with a high fluorescence quantum yield. The device is both cheap and easy to fabricate, and has the potential to be used in practical electro-optic applications.     

互连电缆电磁辐射的抑制方法研究

在电子设备的电磁兼容(EMC)测试中,被测设备(EUT)的互连电缆电磁辐射较难抑制.本文通过交调干扰分析得出EUT内部的可能产生的频谱,并对这些频谱进行滤波处理,使其耦合到电缆线上的电磁辐射较小,同时对电缆上的电磁辐射进行屏蔽处理,保证EUT能通过EMC的辐射发射测试.     

Exploring a Stable and Dense 3D Lead Chloride Hybrid with Emission of Self-Trapped Excitons toward X-Ray Scintillation

The exceptional photophysical properties of 3D organic–inorganic lead halide hybrids (OILHs) endow their significant potential for usage in optoelectronics, which has sparked intense research on novel 3D OILHs and associated applications. However, constructing new 3D OILHs based on large organic cations suffers from tough challenges due to the limitation of the Goldschmidt tolerance factor rule, let alone further explorations of their practical applications. Herein, a brand-new 3D lead chloride hybrid, (1MPZ)Pb₄Cl₁₀·H₂O ( 1 , 1MPZ = 1-methylpiperazine) is reported, featuring a dense 3D lead chloride framework made of the corner-, edge-, and face-shared lead chloride polyhedra. 1 presents a broadband white light emission with a large Stokes shift and a nanosecond photoluminescence lifetime, which originates from radiative recombination of self-trapped excitons (STEs) induced by the highly distorted structure. Such a reabsorption-free and fast-decayed STEs emission coupling with the dense 3D architecture further enables 1 with effective X-ray scintillation with good sensitivity. Impressively, 1 also shows superior environmental and radiation stability. This study provides a new 3D OILH with appealing luminescence, not only expanding the 3D OILH family but also inspiring the exploitation of their optoelectronic applications.     

DMQA浓度对OLEDs光电性能的影响

为了探讨DMQA掺杂浓度对有机发光器件（OLEDs）光电性能的影响,采用器件结构ITO/PEDOT：PSS/TPD/Alq3：DMQA/LiF/Al,在0.28~4.5 wt%范围内改变DMQA的掺杂浓度,考察了器件的光电性能变化。结果显示,随着升高DMQA掺杂浓度,器件表现为电流略有下降,说明DMQA对载流子传输起阻挡或者陷阱作用;器件发光效率下降明显,说明DMQA分子间作用力较强,存在浓度淬灭效应,而且,器件发光光谱在570~610 nm区间存在肩峰,其强度随着DMQA浓度增加逐步增大,据此推断该肩峰来自于DMQA激基缔合物发射。     

浅谈声发射技术在含能材料研究中的应用

综述了国内外声发射技术的发展及其在含能材料研究中应用进展。从含能材料的声发射特性研究和多项性能试验等方面对含能材料的声发射检测技术和应用途径进行分析和比较，结果表明声发射检测技术作为一种动态无损检测技术，在含能材料的产品质量控制、性能研究、内部损伤的监测与评估以及加工安全监测等方面都有其独特的可靠性和优越性。