基于超薄发光层的有机发光二极管器件的研究

Study on Organic Light-Emitting Diodes Based on Ultrathin Non-doped Emitters

摘要:

文章采用具有电子捕捉能力的橙红色磷光材料iridium（Ⅲ）bis（2-methyldibenzo-[f,h]quinoxaline）（acetylacetonate）（Ir（MDQ）2（acac））作为超薄发光层应用于有机发光二极管中。通过对其厚度的优化,发现当发光层厚度为0.1nm时,器件性能最好,最大电流效率达到了28.1cd/A,明显优于采用掺杂发光层的器件。分析了发光材料的载流子捕捉作用对器件载流子平衡及器件电流效率的影响,发现超薄发光层结构几乎不改变器件的电学特性,不会进一步破坏器件载流子平衡,正因如此,大多数磷光材料都可以采用超薄发光层获得很高的效率。

Abstract:

Electron-trapping phosphorescent emitter, iridium(Ⅲ)bis(2-methyldibenzo-[f,h]quinoxaline)(acetylacetonate) (Ir(MDQ)2(acac)), was adopted as the ultrathin non-doped emissive layer (EML) in organic light-emitting diode (OLED). The maximum current efficiency reached 28.1 cd/A when the thickness of the ultrathin non-doped EML was optimized to 0.1 nm, which is much higher than those of doped EML devices. By analyzing the influence of charge-carrier trapping property of emissive material on charge-carrier balance and current efficiency of the device, it was found that the ultrathin non-doped EML structure does not alter the electrical characteristics of the devices and will not destroy the charge carrier balance, hence most phosphorescent dyes can achieve high efficiency.