Green Synthesis of Blue Light-Emitting Carbon Dots Using Tridax procumbens Leaves: Optical and Electrochemical Studies

Abstract

We report the preparation of biocompatible blue emitting carbon dots (CDs) using Tridax procumbens (T. procumbens) leaf extract as a bio-source. A one-step hydrothermal method was employed to prepare highly effective photoluminescent CDs. As-synthesized CDs were characterized using Ultraviolet-visible spectroscopy (UV-visible), Photoluminescence (PL), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and Confocal Raman spectroscopy techniques. In addition, the third-order optical nonlinearity of the prepared CDs was carried out using Z-scan technique with the help of continuous wave diode pumped Nd:YAG laser (532 nm). The nonlinear optical (NLO) susceptibility, nonlinear absorption coefficient and nonlinear refractive index were calculated. The synthesized CDs exhibited good excitation dependent properties. The CDs/Nafion modified glassy carbon electrode (CDs/Nf/GCE) was prepared and its electrochemical and catalytic properties were evaluated by using cyclic voltammetry (CV). The CDs/Nf/GCE exhibited high electrocatalytic activity for dopamine oxidation in physiological condition. This new CDs/Nf/GCE showed a linear range of Dopamine (DA) detection from 40 to 220 μ M with the limit of detection (LOD) of 2.7 μ M. The stability and reproducibility of the electrode were also investigated which indicated that this green synthesized CDs could be used for the development of electrochemical sensor to determine DA concentration in biological samples. Carbon dots (CDs) was prepared using Tridax procumbens leaf extract as a bio-source by a simple one-pot hydrothermal green route for the first time. The synthesized CDs exhibit good excitation-dependent fluorescent properties. The prepared CDs/Nafion modified glassy carbon electrode (CDs/Nf/GCE) exhibited a linear range of DA detection from 40 to 220 μ M with the limit of detection (LOD) of 2.7 μ M. The nonlinear refractive (n 2 ), non linear absorption coefficient ( β ) and third - order non linear susceptibility ( χ 3 ) of the prepared CDs was determined using Z-scan analysis.