High-Efficiency Tris(8-hydroxyquinoline)aluminum (Alq3) Complexes for Organic White-Light-Emitting Diodes and Solid-State Lighting

✍ Scribed by Dr. César Pérez-Bolívar; Dr. Shin-ya Takizawa; Dr. Go Nishimura; Dr. Victor A. Montes; Prof. Dr. Pavel Anzenbacher Jr.

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 809 KB
• Volume: 17
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.201100707

✦ Synopsis

Abstract

Combinations of electron‐withdrawing and ‐donating substituents on the 8‐hydroxyquinoline ligand of the tris(8‐hydroxyquinoline)aluminum (Alq~3~) complexes allow for control of the HOMO and LUMO energies and the HOMO–LUMO gap responsible for emission from the complexes. Here, we present a systematic study on tuning the emission and electroluminescence (EL) from Alq~3~ complexes from the green to blue region. In this study, we explored the combination of electron‐donating substituents on C4 and C6. Compounds 1–6 displayed the emission tuning between 478 and 526 nm, and fluorescence quantum yield between 0.15 and 0.57. The compounds 2–6 were used as emitters and hosts in organic light‐emitting diodes (OLEDs). The highest OLED external quantum efficiency (EQE) observed was 4.6 %, which is among the highest observed for Alq~3~ complexes. Also, the compounds 3–5 were used as hosts for red phosphorescent dopants to obtain white light‐emitting diodes (WOLED). The WOLEDs displayed high efficiency (EQE up to 19 %) and high white color purity (color rendering index (CRI≈85).