Realization of white organic light-emitting devices using single green emitter by coupled microcavities with two modes

We fabricated a novel white organic light-emitting diode (WOLED) structure based on a single green emitting layer through coupled microcavities
with two modes. By optical simulation and experiment, we showed that the two resonant modes can be adjusted by varying the thickness of the
special layer to shape white light using only a single green emitter. Utilizing tris(8-hydroxyquinoline)aluminum (Alq3) as an emitting layer, we
obtained a series of WOLEDs whose Commission Internationale de L’Eclairage (CIE) coordinates are on the Planckian curve from ð0:334; 0:343Þ
to ð0; 412; 0:393Þ with current efficiencies in the range of 1.45–2.52 cdA%1. A maximum current efficiency of 10.12 cdA%1 and warm white emission
at CIE ð0:439; 0:461Þ have been demonstrated using bis(2-phenylpyridine)(acetylacetonate)iridium(III) [Ir(ppy)2(acac)] as an emitter material.
© 2015 The Japan Society of Applied Physics