Open AccessDesign and fabrication of hybrid MLAs/gratings for the enhancement of light extraction efficiency and distribution uniformity of OLEDs
Author(s) -
Guixiong Chen,
Yalian Weng,
Xiaocong Lai,
Wenwen Wang,
Xiongtu Zhou,
Qun Yan,
Tailiang Guo,
Yongai Zhang,
Chaoxing Wu
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.427258
Subject(s) - microlens , oled , materials science , optics , optoelectronics , photoresist , polydimethylsiloxane , quantum efficiency , lithography , fabrication , lens (geology) , nanotechnology , physics , medicine , alternative medicine , layer (electronics) , pathology
Extracting light from organic light-emitting diodes (OLEDs) and improving the angular distribution are essential for their commercial applications in illumination and displays. In this work, hybrid microlens arrays (MLAs) and gratings with periods and depths in the scale of submicron have been designed and incorporated on the lighting surface of OLEDs for simultaneous enhancement of light outcoupling efficiency and angular distribution improvement. It is found that the augmentation of light extraction efficiency is mainly attributed to the MLAs, while the gratings can improve the viewing angle by increasing the angular distribution uniformity. A novel approach was proposed by combining photoresist thermal reflow, soft-lithography and plasma treatments on polydimethylsiloxane (PDMS) surfaces synergistically to realize gratings on the wavy surface of MLAs. It has been proved that with the hybrid MLAs/gratings, the external quantum efficiency (EQE) of the OLED can reach up to 22.8%, which increased by 24% compared to that of bare OLED. Moreover, the OLED with the hybrid MLAs/gratings showed an obvious lateral enhancement at wider viewing angle.