Emissive ZnO-graphene quantum dots for white-light-emitting diodes

Dong Ick Son, Byoung Wook Kwon, Dong Hee Park, Won Seon Seo, Yeonjin Yi, Basavaraj Angadi, Chang Lyoul Lee, Won Kook Choi

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485 Citations (Scopus)

Abstract

Hybrid nanostructures combining inorganic materials and graphene are being developed for applications such as fuel cells, batteries, photovoltaics and sensors. However, the absence of a bandgap in graphene has restricted the electrical and optical characteristics of these hybrids, particularly their emissive properties. Here, we use a simple solution method to prepare emissive hybrid quantum dots consisting of a ZnO core wrapped in a shell of single-layer graphene. We then use these quantum dots to make a white-light-emitting diode with a brightness of 798 cd m ĝ̂'2. The strain introduced by curvature opens an electronic bandgap of 250 meV in the graphene, and two additional blue emission peaks are observed in the luminescent spectrum of the quantum dot. Density functional theory calculations reveal that these additional peaks result from a splitting of the lowest unoccupied orbitals of the graphene into three orbitals with distinct energy levels. White emission is achieved by combining the quantum dots with other emissive materials in a multilayer light-emitting diode.

Original languageEnglish
Pages (from-to)465-471
Number of pages7
JournalNature Nanotechnology
Volume7
Issue number7
DOIs
Publication statusPublished - 2012 Jul

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All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Son, D. I., Kwon, B. W., Park, D. H., Seo, W. S., Yi, Y., Angadi, B., Lee, C. L., & Choi, W. K. (2012). Emissive ZnO-graphene quantum dots for white-light-emitting diodes. Nature Nanotechnology, 7(7), 465-471. https://doi.org/10.1038/nnano.2012.71