Green Synthesis of Sodium Alginate Capped -CuInS2 Quantum Dots with Improved Fluorescence Properties

R. Jose Varghese, Sundararajan Parani, Olufemi O. Adeyemi, V. R. Remya, El Hadji Mamour Sakho, Rodney Maluleke, Sabu Thomas, Oluwatobi S. Oluwafemi

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


CuInS2 (CIS) quantum dots (QDs) are known to be ideal fluorophores based on their low toxicity and tunable emission. However, due to low quantum yield (QY) and photostability, the surface is usually passivated by a higher bandgap shell (e.g. ZnS). This always resulted in a blue-shifted emission position which is not usually favourable for biological imaging. To address this problem, we herein report the passivation of green synthesized near infra-red emitting glutathione (GSH) capped CuInS2 QDs using different concentration of sodium alginate (SA) at different temperatures. The as-synthesized QDs are small (~ 3.2 nm), highly crystalline and emitted in the near infra-red region. The optical results showed a 36% increase in photostability and a 2-fold increase in quantum yield at ratio 1:8 (SA: CIS) which is suitable for prolonged biological imaging applications. Transmission electron microscope and X-ray diffraction (XRD) analyses showed that the materials are highly crystalline without any change in shape and size after passivation with the biopolymer. [Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)1331-1335
Number of pages5
JournalJournal of Fluorescence
Issue number6
Publication statusPublished - 1 Dec 2020


  • CuInS QDs
  • Nanocomposite
  • Optical materials
  • Photostability
  • Sodium alginate

ASJC Scopus subject areas

  • Biochemistry
  • Spectroscopy
  • Clinical Biochemistry


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