漸進式連接層於有機發光二極體複合發光系統之研究

Abstract

本論文在傳統的真空熱蒸鍍設備上開發新型製程，製作了漸進式連接層之複合式發光體結構。我們使用NPB/BAlq摻雜C545T這組材料作為主發光體及客發光體系統，並與傳統異質接面元件、複合式發光體元件以及漸進式發光層元件相比較，驗證了漸進式連接層之複合式發光體元件能同時擁有較佳的電流效率及元件壽命。NPB/BAlq摻雜C545T之元件，在漸進式發光層結構上出現了濃度焠熄效應，而透過漸進式連接層之引入，搭配複合式發光體結構，不僅能有效模糊異質接面、增加電荷的平衡，使元件之操作壽命提升為傳統異質接面元件的13.6倍。

We introduced novel fabrication method and a composite emitter structure with graded-connecting layer (CG-EML) for OLED by utilizing a conventional R&D thermal-evaporation coater. Hole-transporting NPB/electron-transporting BAlq doped with green fluorescence C545T was selected as the composite system of mixed hosts and guest materials of study to demonstrate the advantages and attributes of the CG-EML OLED. Compared with conventional bi-layer (B-EML), composite-emission layer (C-EML) and graded-emission layer (G-EML) devices, the current efficiency and the lifetime of CG-EML device were superior, especially in suppressing concentration quenching as was found in G-EML device. Lifetime of CG-EML OLED was also 13.6 times better than that of B-EML by the formation of a fuzzy interface that promotes better the charge balance in the doped emitter.