Down-conversion light outcoupling films using imprinted microlens arrays for white organic light-emitting diodes

We have developed down-conversion outcoupling films to enhance the light outcoupling efficiency in white organic light-emitting diodes (OLEDs). The down-conversion outcoupling films consist of outcoupling structures and color conversion materials, which are prepared by a simple solution-based micro-imprint process and are adopted into OLEDs. The down-conversion films successfully realize white light by converting blue rays from blue phosphorescent OLED. The OLEDs based on the down-conversion films with outcoupling structures show a great improvement of power efficiency by a factor of 1.32 compared to the reference OLED based on down-conversion films without outcoupling structures. Furthermore, the influence of a concentration of color conversion materials on color rendering index of OLEDs is investigated. The results strongly indicate that readily fabricated down-conversion light outcoupling films by a simple micro-imprint process are highly promising for enhanced light extraction performance and high color rendering index of white OLEDs.