Blue organic light-emitting diodes with efficient host-dopant energy level alignment

초록

The authors have demonstrated blue organic light-emitting diodes (OLED) with efficient host-dopant energy level alignment using a total of only two organic materials, 2-methyl-9,10-di(2-naphthyl)anthracene (MADN) and 4'-[2-(2-diphenylamino-9,9-diethyl-9H-fluoren-7-yl)vinyl]-p-terphenyl (PFVtPh). MADN, with ambipolar characteristics, has adequate band gap for junction of anode-cathode and multifunctional characteristics as hole-transporting, electron-transporting, and blue host material. PFVtPh doped in MADN had highest occupied molecular orbital and lowest unoccupied molecular orbital in comparison with 1,4-bis[2-(7-N-diphenyamino-2-(9,9-diethyl-9H-fluoren-2-yl))vinyl]benzene (DAF-ph). The optimized blue OLED fabricated in this study showed a maximum external quantum efficiency of 5.84%, a maximum power efficiency of 7.57 lm/W, and Commission Internationale de I'Eclairage coordinates of (0.15, 0.21). This result also showed 10 times higher power efficiency at 10 mA/cm(2) than blue device using DAF-ph dopant with mismatch of host-dopant energy level alignment. (C) 2011 Elsevier B.V. All rights reserved.

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