TY - JOUR
T1 - Manipulating charge-transfer character with electron-withdrawing main-group moieties for the color tuning of iridium electrophosphors
AU - Zhou, Guijiang
AU - Ho, Cheuk Lam
AU - Wong, Wai Yeung
AU - Wang, Qi
AU - Ma, Dongge
AU - Wang, Lixiang
AU - Lin, Zhenyang
AU - Marder, Todd B.
AU - Beeby, Andrew
N1 - Funding information:
This work was supported by a CERG Grant from the Hong Kong Research Grants Council (HKBU 202106P), a Faculty Research Grant from the Hong Kong Baptist University (FRG/05-06/II-71), and One NorthEast through the Nanotechnology UIC programme at Durham University.
Publisher copyright:
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2008/2/11
Y1 - 2008/2/11
N2 - A new and synthetically versatile strategy has been developed for the phosphorescence color tuning of cyclometalated iridium phosphors by simple tailoring of the phenyl ring of ppy (Hppy = 2-phenylpyridine) with various main-group moieties in [Ir(ppy-X)2(acac)] (X = B(Mes)2, SiPh3, GePh3, NPh2, POPh2, OPh, SPh, SO2Ph). This can be achieved by shifting the charge-transfer character from the pyridyl groups in some traditional iridium ppy-type complexes to the electron-withdrawing main-group moieties and these assignments were supported by theoretical calculations. This new color tuning strategy in Ir III-based triplet emitters using electron-withdrawing main-group moieties provides access to IrIII phosphors with improved electron injection/electron transporting features essential for highly efficient, color-switchable organic light-emitting diodes (OLEDs). The present work furnished OLED colors spanning from bluish-green to red (505-609 nm) with high electroluminescence efficiencies which have great potential for application in multicolor displays. The maximum external quantum efficiency of 9.4%, luminance efficiency of 10.3 cd A-1 and power efficiency of 5.0 Im W -1 for the red OLED (X = B(Mes)2), 11.1 %, 35.0 cd A -1, and 26.8 Im W-1 for the bluish-green device (X = OPh), 10.3%, 36.9 cd A-1, and 28.6 Im W-1 for the bright green device (X = NPh2) as well as 10.7%, 35.1 cd A-1, and 23.1 Im W-1 for the yellow-emitting device (X = SO2Ph) can be obtained.
AB - A new and synthetically versatile strategy has been developed for the phosphorescence color tuning of cyclometalated iridium phosphors by simple tailoring of the phenyl ring of ppy (Hppy = 2-phenylpyridine) with various main-group moieties in [Ir(ppy-X)2(acac)] (X = B(Mes)2, SiPh3, GePh3, NPh2, POPh2, OPh, SPh, SO2Ph). This can be achieved by shifting the charge-transfer character from the pyridyl groups in some traditional iridium ppy-type complexes to the electron-withdrawing main-group moieties and these assignments were supported by theoretical calculations. This new color tuning strategy in Ir III-based triplet emitters using electron-withdrawing main-group moieties provides access to IrIII phosphors with improved electron injection/electron transporting features essential for highly efficient, color-switchable organic light-emitting diodes (OLEDs). The present work furnished OLED colors spanning from bluish-green to red (505-609 nm) with high electroluminescence efficiencies which have great potential for application in multicolor displays. The maximum external quantum efficiency of 9.4%, luminance efficiency of 10.3 cd A-1 and power efficiency of 5.0 Im W -1 for the red OLED (X = B(Mes)2), 11.1 %, 35.0 cd A -1, and 26.8 Im W-1 for the bluish-green device (X = OPh), 10.3%, 36.9 cd A-1, and 28.6 Im W-1 for the bright green device (X = NPh2) as well as 10.7%, 35.1 cd A-1, and 23.1 Im W-1 for the yellow-emitting device (X = SO2Ph) can be obtained.
UR - http://www.scopus.com/inward/record.url?scp=40449111613&partnerID=8YFLogxK
U2 - 10.1002/adfm.200700719
DO - 10.1002/adfm.200700719
M3 - Journal article
AN - SCOPUS:40449111613
SN - 1616-301X
VL - 18
SP - 499
EP - 511
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 3
ER -