Realization of Excitation Wavelength Independent Blue Emission of ZnO Quantum Dots with Intrinsic Defects

Title
Realization of Excitation Wavelength Independent Blue Emission of ZnO Quantum Dots with Intrinsic Defects
Authors
최원국김홍희이연주이윤재정준경이연진박철민임상엽Basavarj Angadi고금진강재욱
Keywords
ZnO; ZnO-GO; excitation wavelength; blue emission
Issue Date
2020-04
Publisher
ACS photonics
Citation
VOL 7, NO 3-734
Abstract
Ecofriendly cation metal oxide quantum dots (QDs) are one of the promising candidates to replace for QDs containing expensive indium (In) or hazardous Cd- and Pb-elements. Super-Eg excitation wavelength (λex) dependent Zni-VO complex defects related characteristic emissions of green, yellow, and orange-red from ZnO QDs are completely inhibited by reducing oxygen vacancies through the hybridization of Zn interstitials in ZnO QDs with antibonding O-states of graphene oxide (GO) QDs. Thus, only λex independent violet-purple-blue (V-P-B) emission resulting from transitions among Frenkel pairs (Zni0-VZn) and the defects Zni0-Oi in ZnO-GO QDs with a high photoluminescence quantum yield (PLQY) of 92% is successfully achieved. White-light emission from PL QD-LEDs is achieved using a mixture of ZnO and ZnO-GO QDs with CIE (0.32, 0.34) excited by a UV LEDs chip (λ = 365 nm). Further, ZnO-GO QD-based deep-blue LEDs (λ = 438 nm) with luminance of 1980 cd/m2, a luminous efficacy (LE) of 2.53 cd/A, and external quantum efficiency (EQE) of 2.78% with CIE (0.16, 0.11) are also realized.
URI
http://pubs.kist.re.kr/handle/201004/71304
ISSN
2330-4022
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KIST Publication > Article
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