有机电致发光器件的热学特性分析

采用COMSOL有限元分析软件的固体传热模块,对有机电致发光器件（OLED）的热学特性进行了仿真,发现器件温度随着输入功率成线性增大。在驱动电流为150 mAcm-2时,仿真结果表明,Alq3发光层的最高温度为82.994 3℃;玻璃基板下表面的最高温是77.392 6℃;器件阴极表面中心区域的最高温度为82.994 2℃,其平均温度为78.445℃。通过改变功能层热传导率、功能层厚度、对流换热系数、表面发射率等参数模拟其对OLED器件热学特性的影响,结果表明,当增加基板的热传导率时,OLED器件温度显著下降而且表面及内部温度梯度大幅减小;提高空气对流换热系数及基板的表面发射率,OLED的温度可以大幅减小。而其他参数则对其影响并不明显。     

Geometrical representation of coherent tunneling process in two-waveguide and three-waveguide coupler

We propose an identical geometrical representation scheme for both Landau–Zener(LZ) tunneling process in twowaveguide coupler with a cubically bent structure and stimulated Raman adiabatic passage(STIRAP) in three-waveguide coupler, similar to the geometrical representation of sum frequency process. The results show that although the twowaveguide coupler with a cubically bent axis has not aperiodic structure, it acts as a chirped quasi-phase-matching(QPM)grating and corrects the relative phase between the two supermodes in the curved coupler system. We present a scheme about how to choose the parameters to design the curved beam splitter.