The effect of microwave power level and post-synthesis annealing treatment on oxygen-based functional groups present on carbon quantum dots

Basim Al Farsi*, R. G.Sumesh Sofin*, Hamood Al Shidhani, El Said I. El-Shafey, Abdullah S. Al-Hosni, Faisal Al Marzouqi, Abey Issac*, Abdulrahman Al Nabhani, Osama K. Abou-Zied

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Despite widespread interest in understanding the properties of carbon quantum dots (CDOTs), there appear to be fewer studies systamaticaly investigating CDOTs' luminescent mechanisms. The primary objective of this study is to prepare CDOTs with desirable optical properties and to understand the photoluminescence (PL) mechanisms involved in order to control the emission charectersitcs. The optical properties of CDOTs are strongly influenced by the functional groups (-OH, –CHO, –COOH, –CO, –COO) formed on the surface of the dots. The key factors affecting the nature and number of functional groups are the preparation method, post synthesis treatment, and the precursor materials. Ascorbic acid was used as the starting material in this study to synthesize CDOTs via microwave-assisted synthesis techniques. Then, the effect of microwave power level and post synthesis annealing temperature on the oxygen-based functional groups present on the surface of the dots was evaluated systematically. It was found that the increasing microwave power level increases the density of functional groups present on the surface of CDOTs, which positively affects the PL. However, annealing at high temperatures decreases the concentration of functional groups and reduces the PL intensity. The PL emission peaks were deconvoluted and the emission wavelength corresponding to each functional group was identified. This work underlines the role of oxygen based functional groups on the PL emission and the ways to control them by physical means.

Original languageEnglish
Article number119326
Pages (from-to)1-14
Number of pages14
JournalJournal of Luminescence
Publication statusPublished - Sept 14 2022


  • Carbon quantum dots
  • Functional groups
  • Microwave synthesis
  • Photoluminescence

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Atomic and Molecular Physics, and Optics
  • General Chemistry
  • Condensed Matter Physics

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