A Novel Neutral Red Derivative for Applications in High-Performance Red-Emitting Electroluminescent Devices

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• 作者：Pengfei Wang ; Zhiyuan Xie ; Shiwen Tong ; Oiyan Wong ; Chun-Sing Lee ; Ningbew Wong ; Liangsun Hung ; and Shuittong Lee
• 刊名：Chemistry of Materials
• 出版年：2003
• 出版时间：May 6, 2003
• 年：2003
• 卷：15
• 期：9
• 页码：1913 - 1917
• 全文大小：96K
• 年卷期：v.15,no.9(May 6, 2003)
• ISSN：1520-5002

文摘

A new compound with intramolecular charge transfer (ICT) character-neutral redderivative (I)-was designed and synthesized. The new compound is strongly fluorescent innonpolar and moderately polar solvents. Using this material as a dopant, we fabricatedelectroluminescent (EL) devices with a structure of indium tin oxide (ITO) coated glass/N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB) (60 nm)/tris(8-hydroxyquinolinato)aluminum (Alq₃):dopant (30 nm)/Alq₃ (20 nm)/Mg-Ag (200 nm). The deviceshowed orange-to-red EL emission with good efficiency and high brightness. The device witha doping concentration of 1 wt % exhibited a high brightness of 18400 cd/m² at a drivingvoltage of 13 V, and the current efficiency is 5.2 cd/A at a current density of 20 mA/cm². Animportant feature of the device is its fairly constant current efficiency over a wide range ofcurrent density from 1 mA/cm² to as high as 500 mA/cm² at different doping concentrations.The current devices show obvious advantages over many reported red-emitting OLEDs, whichshow significant drops in efficiency as the current density and/or dopant concentrationincreases. The present red dopant is particularly suitable for passive-matrix displayapplications where a high excitation density is required.