Известия Саратовского университета. Новая серия Серия: Физика (Sep 2023)

Effect of pH and ionic strength on the photoluminescence of size-fractionated AgInS2/ZnS quantum dots

  • Ponomaryova, Tatiana Sergeevna,
  • Olomskaya, Vera Vladimirovna,
  • Novikova, Anastasiya S.,
  • Goryacheva, Irina Yurievna

DOI
https://doi.org/10.18500/1817-3020-2023-23-3-238-244
Journal volume & issue
Vol. 23, no. 3
pp. 238 – 244

Abstract

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Background and Objectives: Cellular labeling with fluorescent molecules appears to be one of the key methods of cell biology that continues to evolve with the advent of new fluorescent probes possessing unique properties. Ternary AgInS2/ZnS quantum dots occupy a special position comparedto other fluorescentmolecules duetotheir size-adjustable photoluminescence combined with broadband excitation and long emission lifetime. For the use of quantum dots of AgInS2/ZnS composition as a fluorescent probe in in vitro applications, they should have low physiological toxicity and good stability in physiological pH range. The objective of this work is therefore to evaluate the change of photoluminescent properties of AgInS2/ZnS quantum dots with changing pH of the medium and ionic strength. Materials and Methods: To evaluate the effect of pH and ionic strength on the photoluminescence properties of AgInS2/ZnS quantum dots, a size-selective precipitation procedure was carried out and the photoluminescence and absorption spectra of the quantum dot fractions were analyzed. Results: Ternary photoluminescent AgInS2/ZnS quantum dots stabilized in water by thioglycolic acid have been obtained by direct synthesis. Size-selective precipitation allowed to discriminate of 11 AgInS2/ZnS quantum dots fractions from the initial ensemble, revealing distinctly various optical properties. The effect of different pH and ionic strengths on the photoluminescent properties of AgInS2/ZnS quantum dots fractions has been studied. While in strong acidic and basic media the dramatic changes have been observed, the pH and ionic strength range corresponding to the biological fluids has shown no significant influence on the photoluminescent properties of all quantum dots fractions. Conclusion: This indicates the potential application of these nanoobjects as photoluminescent probes in various bioapplications.

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