An Interactive Quantum Dot and Carbon Dot Conjugate for pH-Sensitive and Ratiometric Cu2+ Sensing

Kafeel Ahmad; Sonit Kumar Gogoi; Raihana Begum; Md Palashuddin Sk; Anumita Paul; Arun Chattopadhyay

doi:10.1002/cphc.201601249

An Interactive Quantum Dot and Carbon Dot Conjugate for pH-Sensitive and Ratiometric Cu²⁺ Sensing

Chemphyschem. 2017 Mar 17;18(6):610-616. doi: 10.1002/cphc.201601249. Epub 2017 Jan 25.

Authors

Kafeel Ahmad¹, Sonit Kumar Gogoi², Raihana Begum¹, Md Palashuddin Sk¹, Anumita Paul¹, Arun Chattopadhyay^{1

3}

Affiliations

¹ Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
² Department of Chemistry, Gauhati University, Guwhati, Assam, India.
³ Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.

PMID: 28042907
DOI: 10.1002/cphc.201601249

Abstract

Herein we report the photoinduced electron transfer from Mn²⁺ -doped ZnS quantum dots (Qdots) to carbon dots (Cdots) in an aqueous dispersion. We also report that the electron transfer was observed for low pH values, at which the oppositely charged nanoparticles (NPs) interacted with each other. Conversely, at higher pH values the NPs were both negatively charged and thus not in contact with each other, so the electron transfer was absent. Steady-state and time-resolved photoluminescence studies revealed that interacting particle conjugates were responsible for the electron transfer. The phenomenon could be used to detect the presence of Cu²⁺ ions, which preferentially, ratiometrically, and efficiently quenched the luminescence of the Qdots.

Keywords: copper; electron transfer; electrostatic interactions; quantum dots; sensors.