有机电致发光器件中载流子传输与复合的调控

在典型的多异质结器件ITO/NPB/CBP：Ir（ppy）3/Bphen/Alq3/LiF/Al的基础上,利用有机半导体掺杂技术,设计制备了单异质结-单发光层器件、单异质结-p-i-n结构器件、单异质结-双发光层器件及无异质结-混合主体结构器件,并对其光电性能进行了研究和比较.其中,单异质结-p-i-n结构器件的最大功率效率为32.1lm/W,是参考器件的3.1倍,寿命是参考器件的15倍.无异质结-混合主体结构器件的最大功率效率为37.2lm/W,是参考器件的3.5倍,其寿命是参考器件的46倍.研究结果表明,通过对载流子传输层和发光层的优化设计,构建电子、空穴传输平衡的载流子传输层和发光层,减少或取消异质结界面仍可以实现对载流子传输和复合的有效调控,从而使器件的发光效率和寿命同时得到提高.本研究将为高性能OLED的设计提供实验基础.

Controllable transport and recombination of charge carriers in the electrophosphorescent organic light-emitting devices

A traditional multi-heterojunction device with the structure of ITO/NPB/CBP：Ir（ppy）3/Bphen/Alq3/LiF/Al was fabricated as a reference. Based on this reference, a series of optimized devices with single-heterojunction/ single-emitting-layer, single-heterojunction/p-i-n structure, single-heterojunction/double-emitting-layer and no-hetero- junction/the mixed-host structure were prepared by the electric doping technology of organic semiconductor. Their optical and eletrical properties were inverstigated comparatively. The p-i-n device with single-heterojunction achieved a peak power efficiency of 32.1 lm/W, which was about 2.1 times higher than that of the referential multi-heterojunction device. Moreover, the operational lifetime was 15 times that of the referential device. The mixed-host device without heterojunction obtained a peak power efficiency of 37.2 lm/W, which was about 3.5 times that of the referential one. And the operational lifetime was prolonged to 46 times of that of the referential device. The results demonstrated that the transport and recombination of charge carriers could still be controlled effectively by balancing electron and hole transport in charge carrier transport layers and emitting layer, when reducing and eliminating the heterojunction interfaces, so the efficiency and operational lifetime of devices could be improved simultaneously. This study provides an experimental base for the design of high performance OLEDs.