Facile Synthesis of Fluorescent Carbon Nanodots from Soursop Peel as a Carbon Source for Ferric Metal Ion Sensor

In this work, we present a simple fabrication process of carbon nanodots (C-dots) from soursop peel as a carbon source. The aims of this research are to analyze the optical properties of the C-dots and to synthesize the C-dots  as sensors for detecttion of ferric (Fe ³⁺ ) ions. The optical properties of the prepared C-dots were characterized by spectrophotometry of UV−Vis, photoluminescence, and FTIR. Whereas the synthesis process was conducted by blending with FeCl₃H₂O. The prepared C-dots emitted blue emission color. They had an absorption peak at 278 nm corresponding to the characteristic of π →π* transition. When excited by an excitation wavelength of 340 nm, the PL peak at 430 nm corresponded to their blue emission color. Thus, the appearance of the O-H and C=O bonds in the FTIR spectrum demonstrated that the surface of C-dots was coated by hydroxyl and carbonyl groups, respectively. Interaction between  C–dots and Fe ³⁺ ion, investigated over quenching of the PL intensity of the C-dots after each addition of Fe ³⁺ ion, demonstrated that the C-dots can be applied as a sensor for Fe ³⁺ ion detection. The value of the limit of detection and limit of quantification from Fe ³⁺ ion were determined to be 0.26 mM, These research results could, therefore, pave a large opportunity to explore C-dots from soursop peel for detection of Fe ³⁺ ion in biosensing, in vivo bioimaging, biomedicine, light-emitting diodes, and so on.