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High‐Efficiency Tris(8‐hydroxyquinoline)aluminum (Alq 3 ) Complexes for Organic White‐Light‐Emitting Diodes and Solid‐State Lighting
Author(s) -
PérezBolívar César,
Takizawa Shinya,
Nishimura Go,
Montes Victor A.,
Anzenbacher Pavel
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201100707
Subject(s) - 8 hydroxyquinoline , aluminium , oled , white light , tris , materials science , solid state , light emitting diode , diode , white (mutation) , optoelectronics , chemistry , inorganic chemistry , metallurgy , nanotechnology , layer (electronics) , biochemistry , gene
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).