研制了在传统双层有机电致发光器件(OLED) ITO/NPB/AlQ/Al的阳极与空穴传输层间加入ZnO缓冲层的新型器件.研究了加入缓冲层后对OLED性能的影响,并比较了新型与传统OLED的性能,结果表明,新型器件比传统器件的耐压能力有了显著提高;当电压达到7 V时,发光效率提高了35%.分析认为,ZnO缓冲层的加入,改善了界面, 减少了漏电流,并且阻碍了空穴的注入,有利于改善空穴和电子的注入平衡,提高复合效率.
Organic EL devices using ZnO as a hole-injecting buffer layer have been prepared. The structure of the device is ITO/ZnO/NPB/AlQ/Al. The insertion of this thin film with higher work function can improve the ITO surface and reduce drain current, which makes the device much steady and have a higher break-down voltage. ZnO buffer layer can also block the hole injection at the interface of anode and hole transporting layer,which can be attributed to the more balanced carriers concentration in emissive layer and raise the EL efficiency. The EL efficiecy of device with ZnO buffer is about 35% at 7 V which is higher than that of the device without it.