Mixed spacer effect of hybrid white organic light-emitting diodes for reduced efficiency roll-off

The authors have demonstrated mixed spacer (MS) effect of hybrid white organic light-emitting diodes (HWOLEDs) for reduced efficiency roll-off using fluorescent blue emitter and phosphorescent red emitter. The optimized HWOLED with MS ratio (1:3) which was 4,4',4"tris (N-carbazolyl) triphenylamine and bis-(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminium exhibited a maximum luminance of 42200 cd/m² at 8.5 V, external quantum and power efficiencies of 10.3% and 19.0 lm/W, and Commission Internationale de I'Eclairage coordinates of (0.40, 0.41) at 1 000 cd/m².