电极修饰层PEO/LiF对聚合物发光二极管发光性能的提高

Performance of Polymer Light-Emitting Diodes with Cathode Modify Layers PEO/LIF

在以聚合物发光材料poly(2-methoxy-5-(2-′ethylhexyloxy)-1,4-phenylene vinylene)(MEH-PPV)为发光层的聚合物发光二极管(PLEDs)的金属阴极与聚合物发光层之间插入一层绝缘的聚合物poly(ethyleneoxide)(PEO),发光器件的发光性能有所提高,尤其是PEO/LiF共同对Al电极修饰时发光器件的开启电压、发光强度、电流效率等性能显著提高。初步分析表明修饰层的插入造成了发光聚合物层与金属电极界面形成势垒,通过空穴堆积抑制空穴的注入,增加电子的注入,并且PEO层可以有效抑制激子在阴极的猝灭。

Polymer light-emitting diodes（PLEDs）devices based on MEH-PPV were fabricated. The performance of PLEDs device with inserting insulating layer PEO nserted between the metal cathode and emissive polymer was enhanced. Furthermore, when cathode A1 was modified by PEO/LiF, the threshold, the luminescence intensity, the efficiency and stability of the device were improved significantly. Experiment results show that the improvement of the device performance is caused by the introduction of PEO. The PEO between the metal cathode and emissive polymer works as the carrier barrier for carriers, and the injection of holes is restrained by the accumulation of holes on the surface. Meanwhile, electron injection is enhanced, and the dissociation of exciton is reduced.