Insights into the photoluminescence properties of gel-like carbon quantum dots embedded in poly(methyl methacrylate) polymer

Joana Rodrigues, Sónia O. Pereira, S. Soreto Teixeira, Yiqun Zhou, Zhili Peng, Piumi Y. Liyanage, Roger Leblanc, Ana M.M.V. Barros-Timmons, Luis C. Costa, Florinda M. Costa, Teresa Monteiro

Research output: Contribution to journalArticle

Abstract

Carbon dots (CDs) have become one of the most investigated nanomaterials in the last few years, since they offer excellent prospects to be used in a wide range of technological applications. Nonetheless, the understanding of the photoluminescence (PL) processes remains unclear and solely based on spectroscopic measurements at room temperature, which hampered a full discussion on the nature of recombination mechanisms. Insights into the CDs’ PL and corresponding recombination models can be achieved from temperature, excitation energy and excitation density dependency studies. Thus, in this paper, CDs with a mean diameter of ∼3.0 nm were embedded in poly(methyl methacrylate) (PMMA) and studied by such optical techniques. The recombination of CDs/PMMA composites was found to be due to an overlap of emitting centres, both in the blue and green regions, with intensity and peak position strongly dependent on the excitation density. Moreover, this emission was found to be preferentially populated by two overlapped excitation bands. Temperature-dependent PL measurements corroborate the hypothesis of overlapped emitting optical centres (e.g. small molecules at the CDs’ surface), as no shift on peak position and no changes in spectral shape were observed, which allow to exclude the hypothesis of a conventional free excitonic transition and quantum confinement effects, as observed in typical nanosized semiconductors with dimensions lower than the exciton Bohr radius.

LanguageEnglish (US)
Pages32-38
Number of pages7
JournalMaterials Today Communications
Volume18
DOIs
StatePublished - Mar 1 2019

Fingerprint

Excitation energy
Polymethyl Methacrylate
Polymethyl methacrylates
Semiconductor quantum dots
Esters
Photoluminescence
Polymers
Temperature distribution
Carbon
Gels
Quantum confinement
Nanostructured materials
Excitons
Temperature
Semiconductor materials
Molecules
Composite materials

Keywords

  • CDs/PMMA
  • Excitation density dependence
  • Excitation energy dependence
  • Photoluminescence
  • Photoluminescence excitation
  • Temperature dependence

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Materials Chemistry

Cite this

Insights into the photoluminescence properties of gel-like carbon quantum dots embedded in poly(methyl methacrylate) polymer. / Rodrigues, Joana; Pereira, Sónia O.; Soreto Teixeira, S.; Zhou, Yiqun; Peng, Zhili; Liyanage, Piumi Y.; Leblanc, Roger; Barros-Timmons, Ana M.M.V.; Costa, Luis C.; Costa, Florinda M.; Monteiro, Teresa.

In: Materials Today Communications, Vol. 18, 01.03.2019, p. 32-38.

Research output: Contribution to journalArticle

Rodrigues, J, Pereira, SO, Soreto Teixeira, S, Zhou, Y, Peng, Z, Liyanage, PY, Leblanc, R, Barros-Timmons, AMMV, Costa, LC, Costa, FM & Monteiro, T 2019, 'Insights into the photoluminescence properties of gel-like carbon quantum dots embedded in poly(methyl methacrylate) polymer' Materials Today Communications, vol. 18, pp. 32-38. https://doi.org/10.1016/j.mtcomm.2018.10.014
Rodrigues, Joana ; Pereira, Sónia O. ; Soreto Teixeira, S. ; Zhou, Yiqun ; Peng, Zhili ; Liyanage, Piumi Y. ; Leblanc, Roger ; Barros-Timmons, Ana M.M.V. ; Costa, Luis C. ; Costa, Florinda M. ; Monteiro, Teresa. / Insights into the photoluminescence properties of gel-like carbon quantum dots embedded in poly(methyl methacrylate) polymer. In: Materials Today Communications. 2019 ; Vol. 18. pp. 32-38.
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