Stabilized blue emission from polyfluorene-based light-emitting diodes: Elimination of fluorenone defects

被引：365

作者：

Gong, XO ^{[1
]}

Iyer, PK

Moses, D

Bazan, GC

Heeger, AJ

Xiao, SS

机构：

[1] Univ Calif Santa Barbara, Inst Polymers & Organ Solids, Santa Barbara, CA 93106 USA

[2] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA

[3] Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA

[4] Amer Dye Source Inc, Quebec City, PQ H9X 3T6, Canada

来源：

ADVANCED FUNCTIONAL MATERIALS | 2003年 / 13卷 / 04期

关键词：

D O I：

10.1002/adfm.200304279

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Polyfluorene (PF)-based light-emitting diodes (LEDs) typically exhibit device degradation under operation with the emergence of a strong low energy emission band (at similar to2.2-2.4 eV). This longer wavelength band converts the desired blue emission to blue-green or even yellow. We have studied both the photoluminescence (PL) and electroluminescence (EL) of PFs with different molecular structures and found that the low-energy emission band originates from fluorenone defects which are introduced by photo-oxidization, thermal oxidation, or during device fabrication. X-ray photo-emission spectroscopy (XPS) results show that the oxidation of PF is strongly catalyzed by the presence of calcium. The fluorenone defects generate a stronger contribution to the EL than to the PL. By utilization of a novel electron-transporting material as a buffer layer between the emissive PF and the Ca/Ag (Ba/Ag) cathode, the blue EL emission from the PF was stabilized.

引用

页码：325 / 330

页数：6

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