White top-emitting organic light-emitting devices(TEOLEDs) with very low efficiency roll-off are obtained by utilizing Ag/Alq
3
/Ag/Alq
3
/Ag as an anode. A neat bipolar transport 4
4'-bis(9-carbazolyl)-2
2'-biphenyl(CBP) layer is introduced between the blue fluorescent and the orange phosphorescent emission layers in order to reduce the Dexter energy transfer between the two emissive units
which can improve the emission spectrum and device efficiency. The yellow emission from bis(2-(2-fluorphenyl)-1
3-benzothiozolato-N
C2') iridium(acetylacetonate) is manipulated by optimizing the microcavity effect of the TEOLED. As a result
we demonstrate that a very low roll-off of 17% for the current efficiency can be obtained at a super high luminance of 60 000 cd/m
2
. The efficiencies of the white TEOLEDs are comparable to those of the corresponding conventional bottom-emitting OLED. In comparison
the efficiency roll-off of the TEOLEDs is much lower than that of the corresponding conventional bottom-emitting device due to the microcavity effects.
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