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Highly Efficient Simplified Organic Light-Emitting Diodes Utilizing F4-TCNQ as an Anode Buffer Layer 下载免费PDF全文
We demonstrate that the electroluminescent performances of organic light-emitting diodes (OLEDs) are significantly improved by evaporating a thin F4-TCNQ film as an anode buffer layer on the ITO anode. The optimum Alq3-based OLEDs with F4-TCNQ buffer layer exhibit a lower turn-on voltage of 2.6 V, a higher brightness of 39820cd/m^2 at 13 V, and a higher current efficiency of 5.96cd/A at 6 V, which are obviously superior to those of the conventional device (turn-on voltage of 4.1 V, brightness of 18230cd/m^2 at 13 V, and maximum current efficiency of 2.74calla at 10 V). Furthermore, the buffered devices with F4-TCNQ as the buffer layer could not only increase the efficiency but also simplify the fabrication process compared with the p-doped devices in which F4-TCNQ is doped into β-NPB as p-HTL (3.11 cd/A at 7 V). The reason why the current efficiency of the p-doped devices is lower than that of the buffered devices is analyzed based on the concept of doping, the measurement of absorption and photoluminescence spectra of the organic materials, and the current density-voltage characteristics of the corresponding hole-only devices. 相似文献
996.
用KMR模型研究了等离子体中多光子非线性Compton散射下电子相轨道的演化,发现电子与光子进行能量交换后,只有未被俘获电子的相轨道才能从周期性向非周期性、随机型演化,其演化剧烈程度随电子吸收光子数的增大而加剧,随电子与光子碰撞非弹性成分和碰撞前初始速度的增大而迅速减弱,但低于强激光场中的剧烈程度。当电子被光场俘获时,这种演化过程结束并做稳定的运动,光子不再为电子提供能量。 相似文献
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We present a comparison between intracavity cooling and external cavity cooling for optical refrigeration. The results show that the intracavity scheme is preferred at low optical densities (〈 0.008), while the external cavity scheme is preferred at higher optical densities (〉 0.01). We can choose the proper scheme for different eases in experiments. Moreover, under the same conditions, taking Yb^3+-doped ZBLAN (ZrF4-BaF2-LaF3-AlFa-NaF) film as an example, the cooling processes of the two scheme are obtained. The calculated results show that intracavity cooling will achieve a larger temperature drop for a thin film sample. Finally, the diode laser may become a candidate for the intraeavity model briefly discussed. 相似文献
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CHEN RuiLin ZENG QingYuan HUANG YunQing XIANG Jun WEN Ying GUO XiaoGang YIN ChangJun DONG Hui & ZHAO Gang Hunan Key Laboratory for Computation Simulation in Science Engineering Xiangtan University Xiangtan China School of Civil Engineering & Mechanics School of Civil Architecture Central South University Changsha AMEC Toronto MAG Canada 《中国科学:物理学 力学 天文学(英文版)》2010,(4)
Based on the analysis theory of random energy of train derailment, an analysis theory of random energy of train derailment in wind is suggested. Two methods are proposed -the time domain method and the frequency domain method of analysis theory of random energy of train derailment in wind. The curves of σ pw -v under various wind speeds are obtained through the computation. The original curve of σ p -v is expanded, which turns the analysis theory of random energy of train derailment into the all-weather theory. Train derailment condition has been established under wind action. The first and second criterions of train derailment have been proposed in light of wind action. The analysis of train derailment cases at home or abroad is made, in- cluding the first analysis of Xinjiang train derailment case encountered 13-level of gale, which explained the inevitability of train derailment. The analysis theory of random energy of train derailment in wind shows its validity and accuracy. The input energy σ pw of the transverse vibration of train-track(bridge)-wind system is linked to train speed. With the establishment of the analysis theory of random energy of train derailment in wind, It is likely to initiate an all-weather speed limit map for a train or any high-speed train. 相似文献
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Co-occurrence of Dominant Direct and Indirect Transitions in Low Temperature Sputtered Indium Tin Oxide Thin Films on Polymers 下载免费PDF全文
Indium tin oxide (ITO) layers are prepared on polymethylmethacrylate and polyethylene terephthalate by rf- magnetron sputtering at room temperature. Their 3D-AFM images and visible transmittance spectra are contrastively characterized and studied. An interesting morphological effect of the polymer substrates on their top ITO layers is observed. Dominant direct and indirect transition types deduced from optical spectra are surprisingly found in ITO films on different polymers. Furthermore, qualitative band structures are figured, and some theoretical discussions about the correlation of optical band structure, interface/surface morphology and carrier density are also presented. 相似文献