具有穿插界面结构的高效绿光有机电致磷光器件

High Efficienct Green-light Organic Phosphorescent Device with Interinserting Interface Structure

以传统有机电致磷光器件ITO/NPB/CBP∶Ir(ppy)3/BAlq/Alq3/LiF/Al为研究对象,在NPB/CBP∶Ir(ppy)3、CBP∶Ir(ppy)3/BAlq及BAlq/Alq3界面处构造交互穿插结构。器件的光电性能测试表明:交互穿插结构一方面能够降低电流密度,减少高电流密度下磷光猝灭中心的形成;另一方面能增加载流子复合界面面积,从而分散界面三线态激子,降低三线态-三线态激子的猝灭。此外,界面凸起的存在还有利于器件的光耦合输出。实验结果表明:当穿插厚度为10 nm,器件的最大电流效率达到34.0 cd/A,与传统器件的电流效率18.7 cd/A相比,提高了55%。

On the basis of a traditional phosphorescent organic light emitting device（PHOLED） with the structure of ITO/NPB/CBP∶Ir（ppy）3/BAlq/Alq3/LiF/Al,a new structure PHOLED was fabricated in this paper,where concavo-convex shape was constructed at the NPB/CBP∶Ir（ppy）3,CBP∶Ir（ppy）3/BAlq and BAlq/Alq3 interface.A series of measurements of optical and electrical properties of device indicated that,（1） this concavo-convex interface structure with suitable protrusion thickness can reduce current density of device,hence reduce the formation of phosphorescence quench centers induced by high current density,（2） it can increase the area of charge carrier recombination interface and then disperse triplet excitons,hence decrease triplet-triplet quenching,（3） it can enhance the out-coupling of the waveguide light without spectral distortion.Therefore,this new structure with suitable protrusion thickness can increase remarkably the current efficiency of the device.When the protrusion thickness was 10 nm,the maximum current efficiency of the device can reach to 34.0 cd/A with an increase of 55% compared with the traditional device.