Size-dependent structural and optical characteristics of glucose-derived graphene quantum dots

Libin Tang, Rongbin Ji, Xueming Li, Kar Seng Teng, Shu Ping Lau

Research output: Journal article publicationJournal articleAcademic researchpeer-review

129 Citations (Scopus)

Abstract

It is of scientific importance to obtain graphene quantum dots (GQDs) with narrow-size distribution in order to unveil their size-dependent structural and optical properties, thereby further to explore the energy band diagram of GQDs. Here, a soft-template microwave-assisted hydrothermal method to prepare GQDs with diameters less than 5 nm ± 0.55 nm is reported. The size-dependent photoluminescence (PL) quantum yield (QY) decay lifetime and electron energy loss spectroscopy (EELS) of the GQDs are studied systematically. The QY of the GQDs with an average diameter of 2 nm is the highest (15%) among all the samples investigated and the QY decreases with increasing diameter of the GQDs. The size-dependence of the PL decay lifetime is also observed. The result suggests that spatial confinement effects related to radiative relaxation play an important role in the size-dependent decay lifetime. A realistic energy band diagram of the GQDs is deduced from the experimental results. KGaA, Weinheim.
Original languageEnglish
Pages (from-to)523-531
Number of pages9
JournalParticle and Particle Systems Characterization
Volume30
Issue number6
DOIs
Publication statusPublished - 1 Jun 2013

Keywords

  • electron energy loss spectroscopy
  • graphene
  • quantum dots
  • soft templates
  • time-resolved photoluminescence

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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