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501.
We report on few-layer graphene synthesized on Cu foils by ion implantation using negative carbon cluster ions,followed by annealing at 950?C in vacuum.Raman spectroscopy reveals IG/I2Dvalues varying from 1.55 to 2.38 depending on energy and dose of the cluster ions,indicating formation of multilayer graphene.The measurements show that the samples with more graphene layers have fewer defects.This is interpreted by graphene growth seeded by the first layers formed via outward diffusion of C from the Cu foil,though nonlinear damage and smoothing effects also play a role.Cluster ion implantation overcomes the solubility limit of carbon in Cu,providing a technique for multilayer graphene synthesis. 相似文献
502.
The dynamics of polymer chains in layered silicate/polystyrene nanocomposites was studied by anelastic spectroscopy. Two thermal activated peaks (α and α′ peaks) appeared when the specimens were heated to a high temperature and they were related to glass transition and liquid-liquid transition, respectively. The activation energy was calculated based on Arrhenius equation and it showed that the activation energy of glass transition (E g) is much higher than that of liquid-liquid transition (E ll). Furthermore, the most interesting result for the activation energy was that there were two contrary trends for E g and E ll, E g decreased and E ll increased with the addition of clay platelets. The fragile parameter was analyzed and the variation of fragile parameters for the two transitions was also contrary to each other with the addition of clay platelets. All the results indicated that the confinement effect of clay platelets on the dynamics of polymer chain was scale dependent, and perhaps, the two transitions were produced by different mechanisms. 相似文献
503.
有机电致发光器件中载流子传输与复合的调控 总被引:1,自引:0,他引:1
在典型的多异质结器件ITO/NPB/CBP:Ir(ppy)3/Bphen/Alq3/LiF/Al的基础上,利用有机半导体掺杂技术,设计制备了单异质结-单发光层器件、单异质结-p-i-n结构器件、单异质结-双发光层器件及无异质结-混合主体结构器件,并对其光电性能进行了研究和比较.其中,单异质结-p-i-n结构器件的最大功率效率为32.1lm/W,是参考器件的3.1倍,寿命是参考器件的15倍.无异质结-混合主体结构器件的最大功率效率为37.2lm/W,是参考器件的3.5倍,其寿命是参考器件的46倍.研究结果表明,通过对载流子传输层和发光层的优化设计,构建电子、空穴传输平衡的载流子传输层和发光层,减少或取消异质结界面仍可以实现对载流子传输和复合的有效调控,从而使器件的发光效率和寿命同时得到提高.本研究将为高性能OLED的设计提供实验基础. 相似文献
504.
合成了两种金属配合物{[Cu2(pztc)(4, 4'-bpy)(H2O)4]·6H2O}n (1), {(H2bpe)[Cd(pztc)(H2O)2]·2.5H2O}n (2)(H4pztc=吡嗪-2, 3, 5, 6-四甲酸, bpy=4, 4'-联吡啶, bpe=1, 2-二(4-吡啶基)乙烯), 测定了其晶体结构, 并对其进行了红外光谱、荧光光谱和热重分析等表征。两种配合物均为二维层状结构, 但其中吡嗪四酸的配位方式不同。配合物2具有蓝色的荧光, 最大荧光发射峰在475 nm。测试了配合物1的电子顺磁共振谱, 结果显示Cu2+的特征谱带。 相似文献
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The spectral radiance of vacuum ultraviolet (UV) target is of crucial significance to plenty of researches including deep space exploration and spacecraft damage test. Two types of test systems and methods for vacuum UV light sources were studied. Through the research of test method for vacuum UV spectral radiance, a corresponding test system was developed, which included vacuum UV standard light source, optical imaging system, light splitting module, vacuum UV detector module, vacuum chamber and data processing system. According to the direct measurement method and the comparative method, the spectral radiance of deuterium lamps was tested and analyzed, the influencing factors and the relative index error of vacuum UV spectral radiance were discussed, and the accurate measurement of vacuum UV spectral radiance in the five wavelength ranges of 121.2 nm, 135.6 nm, 160 nm, 180 nm, 200 nm at 0.01 μW/cm2·nm·sr~1 μW/ cm2·nm·sr was realized. The repeatability of the measurement is 0.001 34, which shows that the proposed test system can realize the test of vacuum UV signal. © 2022 Editorial office of Journal of Applied Optics. All rights reserved. 相似文献
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采用热舟蒸发方法沉积了氟化镁(MgF2)材料的单层膜,沉积温度从200 ℃上升到350 ℃,间隔为50 ℃。测量了样品的透射率和反射率光谱曲线,进行了表面粗糙度的标定,并在此基础上进行了光学损耗及散射损耗的计算。同时对355 nm波长处的激光诱导损伤阈值进行了测量。结果表明:随着沉积温度的升高,光学损耗增加;在短波长范围散射损耗在光学损耗中所占比例很小,光学损耗的增加主要由吸收损耗引起;在355 nm波长处的损伤阈值变化与吸收损耗的变化趋势相关,损伤机制主要是吸收起主导作用。样品的微缺陷密度也是影响损伤阈值的一个重要因素,损伤阈值随缺陷密度的增加而降低。 相似文献