Conducting carbon quantum dots – a nascent nanomaterial

Abstract

Herein, the conducting properties of poly(4-styrene sulphonate)-stabilized carbon quantum dots (PSS-CQDs) are reported. High-resolution transmission electron microscopy, Fourier transmission infrared spectroscopy and thermogravimetry were used to determine the size, crystalline nature and surface nature of PSS-CQDs. The material showed a strong emissive behavior. The fluorescence excitation spectra of the CQDs showed evidence of low lying energy states, which were responsible for the excitation-dependant fluorescence properties. The current–voltage (I–V) characteristics of individual PSS-CQDs coated on ITO were probed using the spreading resistance imaging mode of an atomic force microscope. The I–V data of individual PSS-CQDs exhibited a linear behaviour at low bias and a sudden jump in current value as the bias crossed zero voltage. Cyclic voltammetry (CV) was used to determine the band gap of the CQDs. I–V behaviour was interpreted using the CV data and fluorescence properties of PSS-CQDs. The study might lead to the development of cheap and green conducting nanomaterials for future applications.