Synthesis of Nitrogen Doped Carbon Quantum Dots (NCQDs) from Dieffenbachia seguine Leaves for Fluorescent pH Sensing

Abstract

Synthesis with the goal of developing new fluorophores and characterizing them to find suitability for various applications is of great importance in energy transfer in optoelectronics and biomedicine, detection of metal ions, etc. In this study, a hydrothermal method was employed to synthesize nitrogen doped carbon quantum dots (NCQDs) as pH sensor materials using Dieffenbachia seguine leaves as a carbon source. A detailed characterization of the NCQDs revealed an absorption spectrum from 200 to 800 nm with multiple peaks and an energy-band gap of 3.58 eV. Carbon was found to have the highest weight percentage, followed by nearly equal amounts of N and O and minor amounts of the other elements. The analysis revealed the presence and crystal morphology of functional groups such as OH, C=C and C–H. Variation of fluorescence intensity with pH was found in the pH range considered from 1 to 10 with a correlation of 0.92. The results of these parameters support the utility of synthetic NCQDs as fluorescent pH sensors.