金属/有机界面势垒对单层有机电致发光器件发光效率的影响

基于高场下电荷的注入过程及激子的解离和复合过程，建立了单层有机发光器件电致发光(EL)效率的理论模型。计算表明：(1)当金属／有机界面势垒高度大于0．3eV时，器件的EL效率很低，降低金属／有机界面势垒可以显著提高器件的EL效率；(2)在较低偏压下，注入过程对器件的电致发光效率起主要作用，但在高偏压下复合过程起支配作用。这一模型可以阐明注入和复合过程对有机发光器件EL效率的影响，对选择发光材料、优化器件结构和提高器件EL效率具有指导意义。

Influence of Metal/Organic Interface Barriers on the EL Efficiency in Single-layer Organic EL Devices

An analytical model to calculate the electroluminescence(EL) profile at high electric field in single layer structure, taking into account the charge injection process at each electrode, fission and recombination of polaron-excitons in disordered system, is presented. The influences of the barriers of metal/organic interface on EL efficiency are thoroughly studied. When the barrier exceeds about 0.3 eV, the EL efficiency will become very small. While lowering the barrier of metal/organic interface, the EL efficiency will be enhanced. With increasing applied voltages,the injection efficiency increases while the recombination efficiency decreases, and when the electric field increases to a critical value, the EL efficiency reaches the maximum and then decreases. It indicates that the EL efficiency is dominated by injection at lower voltages and recombination at higher voltages. It is found this model can reasonably elucidates the influence of injection and recombination processes on EL efficiency, which provides a theory to improve the EL efficiency, to optimize the structure and to select suitable electroluminescent materials.