有机/有机界面污染对有机电致发光器件稳定性的影响

摘要

有机电致发光器件的稳定性是其实用化面临的主要难题之一.为了研究有机/有机界面性质对有机电致发光器件稳定性的影响,采用溶液旋涂的NPB(NPBsc)作为器件的空穴传输层制备了两种异质结电致发光器件:ITO/NPBSC/Alq3/LiF/Al和ITO/NPBsC/NPB/Alq3/LiF/Al,对比研究了器件的发光性能和工作稳定性.研究结果表明:完全使用NPBsc作为空穴传输层的器件性能和稳定性都较差,这归因于不稳定的NPBsc/Alq3界面,在空气中旋涂制备NPB层时,空气中的水蒸气和氧气分子会粘附在空穴传输层表面,这样就会引起界面处Alq3分子的发光猝灭.插入10 nm真空蒸镀的NPB层可以显著地提高器件的发光性能和稳定性,10 nm的NPB层把污染界面与激子复合区界面分开,避免了水蒸气和氧气分子对Alq3分子的发光猝灭,器件的效率增加了1.15 cd/A,半衰期寿命提高了4倍.%Two types of organic light-emitting devices were fabricated using a spin-coated N,N'-di (naphth-1-yl)N,N'-diphenyl-benzidine (NPBsc) film as hole-transport layer (HTL):ITO/NPBsc/Alq3/LiF/Al,ITO/NPBsc/NPB/Alq3/LiF/Al.The effect of air contaminated NPBsc/organic interface on the stability of organic light-emitting devices was investigated.It is found that the device using a NPBsc film as HTL exhibited the poorer stability,which is attributed to the instability of NPBsc/Alq3 interface that contaminated by moisture and oxygen from the NPBsc layer.A vacuum-deposited NPB film (10 nm) inserted between NPBsc layer and Alq3 layer can greatly improve the stability of device by blocking the recombination zone from contamination of moisture and oxygen.