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

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 lm ∕ W , maximum external quantum efficiency of 13.1%, and Commission Internationale de I'Eclairage coordinates ( CIE x , y ) of ( x = 0.37 , y = 0.37 ) .