以膦酸酯聚芴作为阴极界面修饰层的高效聚合物红光电致发光器件

以膦酸酯聚芴为阴极界面修饰层, 高功函金属铝为阴极, 制备了一种高效聚合物红光电致发光器件. 通过X射线光电子能谱(XPS)的表征, 分析了经真空蒸镀沉积在膦酸酯聚芴表面的Al原子与下层的膦酸酯聚芴在有机物-金属界面处的作用情况, 结果表明, 在真空蒸镀金属Al的过程中, 在有机物-金属界面处形成了一种氧/铝复合物. 研究了这种氧/铝复合物对器件光电性能的影响, 结果表明, 氧/铝复合物的产生提高了阴极电子的注入, 使器件效率得到了很大提高. 与以Ca/Al为阴极的传统器件相比, 以膦酸酯聚芴/Al为阴极的聚合物电致发光器件的效率提高了75%, 达到7.0 cd/A.

Efficient Polymer Red Light-emitting Diodes with Cathode Interface Modification Layer Based on Phosphonate Polyfluorene

This work presents the fabrication of efficient red polymer light-emitting diodes by spin coating the alcohol-soluble poly(9,9-bis(6′-diethoxylphosphorylhexyl)fluorene)(PF-EP) onto the surface of the electroluminescent film before the device cathode, made of Al, rather than the low work function metals, such as Ca or Ba, is deposited. By the high-resolution XPS, the interaction of thermally evaporated Al with the PF-EP layer was investigated. The efficiency of PLEDs with an organic oxide/Al composite cathode, reaches 7.0 cd/A, which is markedly higher than the efficiency of 4.0 cd/A of device with Ca/Al cathode. The light-emitting efficiency is increased by 75%. It may provide a way to improve the device performance of polymeric phosphorescent diodes.