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

Hong Hee Kim, Yeonju Lee, Yun Jae Lee, Junkyeong Jeong, Yeonjin Yi, Cheolmin Park, Sang Youp Yim, Basavaraj Angadi, Keum Jin Ko, Jae Wook Kang, Won Kook Choi

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


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 (Zni 0-VZn) and the defects Zni 0-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.

Original languageEnglish
Pages (from-to)723-734
Number of pages12
JournalACS Photonics
Issue number3
Publication statusPublished - 2020 Mar 18

Bibliographical note

Funding Information:
Won Kook Choi gratefully acknowledges the financial support from both the KIST Institutional Program under Contract No. 2E28200 and the Ministry of Science and ICT, Midcareer Researcher Program under Contract No. NRF-2017R1A2B2008115.

Publisher Copyright:
© 2020 American Chemical Society.

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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