Ag@CDs nanohybrid: Fabrication, design of a multi-mode chemosensory probe for selective Fe3+ detection and logic gate operation.

Abstract

In this study, we propose a unique use of silver-carbon dot nanohybrid (Ag@CDs) with an average size of 16nm as a multi-mode sensor for the selective detection of Fe3+ and the construction of logic gates based on these unique detection properties. The Ag NPs exhibit colourimetric sensing and fluorescence quenching in response to Fe3+ in the concentration range of 10-100ppm, with the carbon dots acting as the fluorescent entity. Surprisingly, the nanohybrid was shown to have excellent sensitivity to Fe3+, resulting in aggregation and formation of yellowish-brown clumps. When the reaction mixture was treated with Fe3+, there was a discernible change in the colour of the assay mixture and fluorescence quenching. That is, the Ag@CDs acted as a calorimetric and fluorescence multi-mode sensor. Even in interfering groups in the natural river water sample, the produced nanohybrid displayed good selectivity towards Fe3+, with a minimum LOD of 0.76ppm. Further, we constructed an advanced logic system, IMP-OR gate, by using additional inputs - ascorbic acid and urea.