A Robust Yellow-Emitting Metallophosphor with Electron-Injection/-Transporting Traits for Highly Efficient White Organic Light-Emitting Diodes

• Published in: Chemphyschem 2011-10, Vol.12 (15), p.2836-2843
• Main Authors: Zhou, Guijiang, Yang, Xiaolong, Wong, Wai-Yeung, Wang, Qi, Suo, Si, Ma, Dongge, Feng, Jikang, Wang, Lixiang
• Format: Article
• Language: English
• Subjects: Applied sciences; electron injection; electron transport; Electronics; Exact sciences and technology; fluorescence; Fundamental areas of phenomenology (including applications); Optical sources and standards; Optics; Optoelectronic devices; organic light-emitting diodes; phosphorescence; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201100259

With the aim of endowing triplet emitters in the development of organic light‐emitting devices (OLEDs) with electron‐injection/‐transporting (EI/ET) features, the phenylsulfonyl moiety was introduced into the phenyl ring of a 2‐phenylpyridine (Hppy) ligand and the yellow phosphorescent heteroleptic iridium(III) complex 1 was developed. It was shown that the SO2Ph unit could provide EI/ET character to 1, as indicated from both electrochemical and computational data. Complex 1 is a promising yellow‐emitting material for both monochromatic OLEDs and white OLEDs (WOLEDs). The outstanding electronic traits associated with 1, coupled with careful device design, afforded very attractive electroluminescent performances for two‐element WOLEDs, including a low turn‐on voltage of less than 3.7 V, a maximum brightness of 48 000 cd m−2, an external quantum efficiency of 13.0 %, a luminance efficiency of 34.7 cd A−1, and a power efficiency of 24.3 Lm W−1. In addition, a good color rendering index (CRI) of about 74, a stable white color with a Commission Internationale de L′Eclairage (CIEx,y) variation of Δ(x, y)