Abstract
Ternary I–III–VI quantum dots (QDs) have proved to be promising alternatives to the traditional binary Cd-QDs due to their inherently lower toxicities, greener synthetic methods, and tunable optoelectronic properties. Their application in the development of biosensors, electroluminescent devices, and a range of other electrochemical applications has resulted in the I–III–VI QDs receiving widespread attention in various fields. In this paper, water-soluble glutathione capped AgInS core QDs and AIS/ZnS core/shell QDs were synthesized using an eco-friendly hydrothermal method. Electrochemical properties of the AgInS core QDs and AgInS/ZnS core/shell QDs were evaluated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). DPV of AgInS core QDs exhibited distinguished oxidation peaks centred at ? 0.05 and ? 0.88 V vs Ag/AgCl of Ag and In ions, respectively, while the AgInS/ZnS QDs showed three symmetrically oxidation peaks at potentials ? 0.87, ? 0.66 and ? 0.42 V of Zn, In and Ag ions, respectively. The total number of electrons, electron transport diffusion coefficient, De (in cm2 s1), and surface concentration of soluble species were evaluated and calculated using the Randles-Sevcik equation. The number of electrons was found to be 1.08 and 0.75 for AgInS QDs and AgInS/ZnS QDs, respectively using the Ag peak and the De value of AgInS QDs was greater than AgInS/ZnS QDs. This indicates that the electron diffusion was the slowest in the AgInS/ZnS QDs. The as-synthesized AgInS core QDs and AgInS/ZnS core-shell QDs exhibited chemical and electrochemical composition-dependent properties. This suggests the material is suitable for the development of biosensors.
NSTL
Elsevier