高能量效率與低操作電壓之高分子電激磷光元件

Abstract

本論文探討以[ITO/PEDOT:PSS/PVK:PBD:Ir(mppy)3/陰極]為主要結構的有機綠光磷光發光二極體，在主動層中加入聚乙二醇[poly(ethylene glycol)]，並嘗試不同的陰極材料以探討有機層和金屬間的作用與元件整體表現的影響，以改善磷光發光二極體的操作電壓。在以鋁作為金屬陰極材料時，經過混入聚乙二醇於主動層中，元件發光效率(Efficiency: cd/A)可從原本將近0.28 cd/A提升到15.6 cd/A，更重要的是整個元件的起始電壓從10V降低到5.6V。另外，在以LiF/Ca/Al為金屬陰極材料時，經過加入聚乙二醇到元件主動層內，也可以使元件的起始電壓從4V降低到3V，同時元件效率維持原本標準元件之發光效率23 cd/A，因此可以使整個元件的能量發光效率(Power efficiency: lm/W)從9 lm/W提升到14 lm/W。最後我們也成功地利用此方法改善其他發光顏色元件的特性。

By blending poly(ethylene glycol) (PEG) into the active layer of green electrosphosphorescent devices, the luminance efficiency of the device with Al cathode achieves to 16cd/A.. More importantly, the turn-on voltage was lower than that of the conventional device. In addition, the device performance of this kind device with the LiF/Ca/Al cathode architecture after blending of 10 wt.% PEG was also investigated. It is found that the driving voltage of the device was lower than the conventional device, while the luminance efficiency reminds high. Consequently, a higher power conversion efficiency (14 lm/W) than that of the control device (9 lm/w) has been achieved. Finally, this work also has demonstrated the similar idea is successful for other color triplet device.