Hybrid spacer for high-efficiency white organic light-emitting diodes

Abstract

High-efficient white organic light-emitting diodes (WOLEDs) were fabricated by using the following three different emitting materials: $4^{″}$ -(2,2-diphenylvinyl)-1-[4-($N,N$ -diphenylamino)-styryl]-terphenyl for blue emission, fac-tris(2-phenypyridine) iridium(III) for green emission, and bis(5-benzoyl-2-phenylpyridinato-$C,N$ )iridium(III) (acetylacetonate) for red emission. For higher efficiency, a hybrid spacer (HS) was inserted between each emissive layer (blue-red, red-green, and green-blue emissive layers). It was found that the WOLEDs using HS showed maximum power efficiency of $28.69\mathrm{lm}∕\mathrm{W}$ , maximum external quantum efficiency of 13.1%, and Commission Internationale de I’Eclairage coordinates $\left({\mathrm{CIE}}_{x,y}\right)$ of $(x=0.37,y=0.37)$ .