Holmium(III)¿Carbon Nanodots Hybrid for Fluorescent Quenching Effect in the Oxalate Detection (C2O4)2¿and Their Different Photoinduced Charge Transfer Processes Academic Article in Scopus uri icon

abstract

  • In this work, carbon nanodots (CNDs) were synthesized via a pyrolysis carbonization method using Rosa damascena petals. The synthesized CNDs exhibit optical absorption in the UV region, with a tail extending out into the visible range. When these CNDs interact with Ho3+ions through charge transfer processes, they form an REn+-CNDs hybrid (Rare Earth-CNDs hybrid), resulting in fluorescence quenching in an aqueous solution. This fluorescence can be recovered by allowing the Ho3+-CNDs hybrid to interact with the oxalate anions. An in silico study supports this mechanism through density functional theory (DFT) analysis, which involves a charge transfer process in discrete systems of functionalized Ho3+-C60. The above plot provides an approximation of the behavior of CNDs and highlights the electrostatic interaction in the [Ho(C2O4)3]3¿complex. Based on this phenomenon, an environmentally friendly fluorescent turn-off/on sensor was developed to detect holmium ions Ho3+and oxalate ions in an aqueous solution. The quantitative detection of Ho3+ranges from 1.0 × 10¿5to 1.0 × 10¿4M, while oxalate concentrations vary from 4.5 × 10¿5to 3.6 × 10¿4M. The concentration of both species exhibited a linear relationship with the fluorescence intensity, characterized by a correlation coefficient of R2= 0.9801 and a Stern¿Volmer constant KSV= (1.09 × 104± 6 × 102) M¿1. In addition, the Laplacian and electronic values obtained, within Bader's quantum theory of atoms in molecules, revealed ionic interactions between holmium(III) and oxalate anions. Moreover, an analysis of the Mulliken and Hirshfeld charges confirmed a charge transfer process from CNDs to Ho3+. © 2025 The Authors. Published by American Chemical Society

publication date

  • January 1, 2025