Synthesis and photophysical studies of iridium complexes of new 2,3-diphenylquinoxaline derivatives for organic light-emitting diodes.
For the application to organic light-emitting diodes (OLEDs), the new iridium complex containing 2,3-diphenylquinoxaline (dpqx) derivatives as a ligand were prepared. Variation of the substituents in the dpqx ligand backbone of the complex led to tuning of the emission color. The complexes, Ir(2,3-dpqx-F2)2(acac), Ir(6-F-2,3-dpqx-F2)2(acac) and Ir(6-F-2,3-dpqx-(OMe)2)2(acac) were formed from the two-step reactions of the corresponding ligand with IrCl3 x H2O. In the photoluminescence (PL) spectra, Ir(2,3-dpqx-F2)2(acac), Ir(6-F-2,3-dpqx-F2)2(acac) and Ir(6-F-2,3-dpqx-(OMe)2),(acac) exhibited the luminescence peak at 631 nm, 638 nm and 645 nm, respectively. The OLEDs employing these compounds as a dopant were prepared and their electroluminescence was investigated. In the electroluminescence (EL) spectra, Ir(2,3-dpqx-F2)2(acac), Ir(6-F-2,3-dpqx-F2)2(acac) and Ir(6-F-2,3-dpqx-(OMe)2)2(acac) exhibited the luminescence peak at 630 nm, 644 nm and 667 nm, respectively. The Commission Internationale de L'Eclairage (CIE) coordinates of Ir(2,3-dpqx-F2)2(acac), Ir(6-F-2,3-dpqx-F2)2(acac) and Ir(6-F-2,3-dpqx-(OMe)2)2(acac) were (0.684, 0.311), (0.675, 0.313) and (0.697, 0.289), respectively.
Ahn
So Youn
SY
Department of Information Display, Hongik University, Seoul 121-791, Korea.
Seoa
Ji Hyun
JH
Kim
Young Kwan
YK
Ha
Yunkyoung
Y