Enhanced outcoupling in down-conversion white organic light-emitting diodes using imprinted microlens array films with breath figure patterns.

We demonstrate high-performance down-conversion microlens array (DC-MLA) films for white organic light-emitting diodes (OLEDs). The DC-MLA films are readily fabricated by an imprinting method based on breath figure patterns, which are directly formed on the polymer substrate with a novel concept. The DC-MLA films result in high-quality white light as well as enhanced light outcoupling efficiency for white OLEDs. The external quantum efficiency and power efficiency of OLEDs with DC-MLA films are increased by a factor of 1.35 and 1.86, respectively, compared to OLEDs without outcoupling films. Moreover, the white OLEDs with DC-MLA films achieve a high color-rendering index of 84.3. It is anticipated that the novel DC-MLA films fabricated by the simple imprinting process with breath figure patterns can contribute to the development of efficient white OLEDs.