Design of lanthanide-doped carbon dots Nanochemosensor for Paper-strip based as well as in-vitro Turn-off–on detection of Fe2+ ions and hydrogen peroxide

Abstract

Shifting emission wavelengths through different excitation methods can provide valuable insights; however, the reduced intensity of the shifted peaks often presents challenges in practical applications. In this work, we report the exceptional enhancement of optical and chemical properties of carbon dots (CDs) by simple doping of erbium ions (Er³⁺ ions). Doping carbon dots (CDs) with Er³⁺ ions can significantly enhance their photoluminescence properties and emission wavelengths are tunable across the entire visible region. The increase in quantum yield from 24.7 % to 30.2 % could enhance the performance of these materials in practical applications. The Er³⁺ ions-doped carbon dots (Er@CDs) are designed via a single-step hydrothermal method and used as a fluorescence probe for signal turn-off–on detections of Fe²⁺ ions and hydrogen peroxide (H₂O₂). The fluorescence signal of Er@CDs is turn-off by the addition of Fe²⁺ ions and turn-on after addition of H₂O₂ with the detection of limits are 51.7 nM & 55 µM, respectively. The fluorescence intensity of Er@CDs turn-off by Fe²⁺ ions may be due to the cation exchange of Er³⁺ ions with Fe²⁺ ions and turn-on via Fenton’s process. This sensing probe follows both dynamic and static quenching mechanism and described by fluorescence lifetime decay and zeta potentials analysis. The synthesized Er@CDs is utilized for paper-based turn-off–on detection of Fe²⁺ ions and H₂O₂. Additionally, the low cytotoxicity and small particle size of the Er@CDs make them ideal for in-vitro turn-off–on detection of Fe²⁺ ions and H₂O₂ in Hep G2 cancer cells.