Open AccessEnhancing extraction efficiency of quantum dot light-emitting diodes by surface engineering
Author(s) -
Qin Zhang,
Xiaobing Gu,
Zihan Chen,
Jie Jiang,
Zhimin Zhang,
Jufu Wei,
Feng Li,
Xiao Jin,
Song Ye,
Qinghua Li
Publication year - 2017
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.25.017683
Subject(s) - quantum efficiency , materials science , optoelectronics , diode , light emitting diode , optics , photon , surface roughness , homogeneity (statistics) , quantum dot , light scattering , substrate (aquarium) , scattering , composite material , physics , computer science , machine learning , oceanography , geology
Light extraction efficiency significantly affects the final performance of quantum dot light-emitting diodes (QLED) devices. Surface engineering of the substrate has been proved to be an effective method to increase the light extraction efficiency. However, a facile, low cost, and scalable process to modify the QLED substrate's surface remains a perpetual topic, which calls for further study. We herein use the wet chemical etching process to roughen the substrate's surface, and a "multi-pits" like exit surface is formed. These "multi-pits" act as scattering centers that benefits homogeneity of the output light. On the other hand, they also give a rise in output coupling efficiency by inhibiting light propagation of the internally generated photons, owing to the suppressed optical waveguide mode. The external quantum efficiency (EQE) of QLED with a roughened surface shows a 12% increase in maximum value, and over 2.2 fold increase at a high driving voltage than that without surface roughening.