An efficient phosphorescent white organic light-emitting diode (WOLED) was realized
by using a bright blue-emitting layer, iridium (III) bis [(4, 6-di-fluoropheny)-pyridinato-N, C2’]
picolinate doped 4.4’-bis (9-carbazolyl)-2, 2’-dimethyl-biphenyl, together with tris (2-
Phenylpyridine) iridium and bis (1-phenyl-isoquinoline) acetylacetonate iridium (III) were codoped
into 4,4’-N,N’-dicarbazole-biphenyl layer to provide blue, green, and red emission for color mixing.
The device emission color was controlled by varying dopant concentrations and the thickness of
blue and green-red layers as well as tuning the thickness of exciton-blocking layer. The maximum
luminance and power efficiency of the WOLED were 37100cd/m2 at 17 V and 7.37lm/W at 5V,
respectively. The Commission Internationale de 1’Eclairage (CIE) chromaticity coordinate changes
from (0.41, 0.42) to (0.37, 0.39) when the luminance rangeed from 1000cd/m2 to 30000cd/m2.
