An Optically Flat Conductive Outcoupler Using Core/Shell Ag/ZnO Nanochurros

Young Zo Yoo, Jin Young Na, Yoon Soo Choi, Yeong Jin Lim, Ji Hyun Kim, Young Bin Kim, Jae Ho Kim, Sun Kyung Kim, Tae Yeon Seong

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Transparent conductive electrodes (TCEs) featuring a smooth surface are indispensable for preserving pristine electrical characteristics in optoelectronic and transparent electronic devices. For high-efficiency organic light emitting diodes (OLEDs), a high outcoupling efficiency, which is crucial, is only achieved by incorporating a wavelength-scale undulating surface into a TCE layer, but this inevitably degrades device performance. Here, an optically flat, high-conductivity TCE composed of core/shell Ag/ZnO nanochurros (NCs) is reported embedded within a resin film on a polyethylene terephthalate substrate, simultaneously serving as an efficient outcoupler and a flexible substrate. The ZnO NCs are epitaxially grown on the {100} planes of a pentagonal Ag core and the length of ZnO shells is precisely controlled by the exposure time of Xe lamp. Unlike Ag nanowires films, the Ag/ZnO NCs films markedly boost the optical tunneling of light. Green-emitting OLEDs (2.78 × 3.5 mm2) fabricated with the Ag/ZnO TCE exhibit an 86% higher power efficiency at 1000 cd m−2 than ones with an Sn-doped indium oxide TCE. A full-vectorial electromagnetic simulation suggests the suppression of plasmonic absorption losses within their Ag cores. These results provide a feasibility of multifunctional TCEs with synthetically controlled core/shell nanomaterials toward the development of high-efficiency LED and solar cell devices.

Original languageEnglish
Article number1800056
Issue number20
Publication statusPublished - 2018 May 17

Bibliographical note

Funding Information:
Y.Z.Y. and J.-Y.N. equally contributed to this work. This work was supported by the Global collaborative R&D program (No. N0002095) through Korea Institute for Advancement of Technology (KIAT) funded by the Ministry of SMEs and Startups, the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT(MOSICT) (NRF-2017R1A2B4005480), and the Global Research Laboratory program through the NRF funded by the MOSICT (NRF-2017K1A1A2013160).

Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • core/shell Ag/ZnO nanochurros
  • optical tunneling
  • organic light-emitting diodes
  • selective-facet growth
  • transparent electrodes

ASJC Scopus subject areas

  • Engineering (miscellaneous)
  • General Chemistry
  • General Materials Science
  • Biotechnology
  • Biomaterials


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