Highly enhanced light extraction from organic light emitting diodes with little image blurring and good color stability

We report a highly enhanced light extraction from a top emission organic light emitting diode with little image blurring and color variation with viewing angle. Direct integration of a high refractive index micro lens array on the top of the transparent indium zinc oxide top electrode of a green phosphorescent OLED showed a significant enhancement of light extraction to get EQE of 44.7% from 27.6%, the power efficiency of 134.7 lm/w from 85.9 lm/W and the current efficiency of 217.2 cd/A from 120.7 cd/A without image blurring. In addition, the device showed excellent color stability on viewing angle with Commission Internationale de l'Eclairage (CIE) coordinate of Delta x = 0.01, Delta y = 0.01 as the viewing angle varied from 0 degrees to 60 degrees. (C) 2014 Elsevier B.V. All rights reserved.