注入和复合对单层有机发光器件电致发光效率的影响

The Influences of Injection and Recombination on the Electroluminescence Efficiency in Single-Layer Organic Light Emitting Devices

考虑电荷的注入、无序系统中载流子的输运及极化子激子的解离和复合过程,建立了单层有机电致发光器件电致发光效率的理论模型.计算并讨论了离化距离对器件复合效率以及注入和复合对器件电致发光效率的影响.结果表明:(1)通过降低金属/有机物界面势垒可以显著提高器件的EL效率;(2)当两电极均为欧姆接触或一个电极欧姆接触,一个电极是接触限制时,在低场下EL效率由注入决定,而高场下复合起主要作用;(3)当两电极均为接触限制时,EL效率主要由注入过程来决定.此模型可以较好地解释一些实验现象.

An analytical model to calculate the electroluminescence （EL） profdes in single layer structure was presented, taking into account the charge injection process at each electrode, hopping transport in disordered system, disassociation and recombination of polaron-excitons.By simulation,the influence of disassociated distance on recombination efficiency and the influence of injection and recombination on EL efficiencies are thoroughly studied. When using both ohmic contacts or an ohmic contact and a contact limited contact, the EL efficiency is determined by injection at lower voltages and recombination at higher voltages. When using both coatact limited contacts, the EL efficiency is determined by the injection process. By comparison of the theoretical results with the experimental data reported in the literature, we found this model can reasonably elucidates the influence of some factors on injection and recombination.