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An Optically Flat Conductive Outcoupler Using Core/Shell Ag/ZnO Nanochurros
Author(s) -
Yoo Young Zo,
Na JinYoung,
Choi Yoon Soo,
Lim Yeong Jin,
Kim JiHyun,
Kim YoungBin,
Kim JaeHo,
Kim SunKyung,
Seong TaeYeon
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201800056
Subject(s) - materials science , optoelectronics , oled , polyethylene terephthalate , substrate (aquarium) , indium tin oxide , electrical conductor , indium , nanowire , energy conversion efficiency , diode , core (optical fiber) , transparent conducting film , layer (electronics) , nanotechnology , composite material , oceanography , geology
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 mm 2 ) 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.