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

Joo Won Han; Chul Woong Joo; Jonghee Lee; Dong Jin Lee; Jisoo Kang; Seunggun Yu; Woo Jin Sung; Nam Sung Cho; Yong Hyun Kim

doi:10.1080/14686996.2018.1551040

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

Sci Technol Adv Mater. 2018 Nov 29;20(1):35-41. doi: 10.1080/14686996.2018.1551040. eCollection 2019.

Authors

Joo Won Han¹, Chul Woong Joo², Jonghee Lee³, Dong Jin Lee¹, Jisoo Kang⁴, Seunggun Yu⁵, Woo Jin Sung², Nam Sung Cho², Yong Hyun Kim¹

Affiliations

¹ Department of Display Engineering, Pukyong National University, Busan, Republic of Korea.
² Flexible Information Device Research Center, Electronics and Telecommunications Research Institute (ETRI), Daejeon, Republic of Korea.
³ Department of Creative Convergence Engineering, Hanbat National University, Daejon, Republic of Korea.
⁴ Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, New York, NY, USA.
⁵ Department of Materials Science and Engineering, Yonsei University, Seoul, Republic of Korea.

Abstract

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.

Keywords: 201 Electronics / Semiconductor / TCOs; 204 Optics / Optical applications, organic light-emitting diodes; 40 Optical, magnetic and electronic device materials; Organic light-emitting diodes; down-conversion; light extraction; outcoupling structures; white OLED.

Grants and funding

This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning [Grant Number 2016R1C1B2012490]. This work was supported partially by the Transfer machine specialized lighting core technology development professional manpower training project funded by the Ministry of TRADE, INDUSTRY & ENERGY (MOTIE, Korea) [Grant Number N0001363]. J. Lee acknowledges the support of the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education [Grant Number 2018R1A6A1A03026005].