Bi2O2Se Nanosheets for Dual-Mode Electrochemical/Fluorescent Turn-off Sensing of Ferric Ions

Abstract

This study investigates a novel dual electrochemical and fluorescent turn-off sensing approach for the selective detection of ferric ions (Fe3+) using exfoliated Bi2O2Se nanosheets (Ex-BOSe NSs), a new class of non-van der Waals 2D materials with excellent optical, electronic, and functional properties. These ultrathin BOSe NSs, synthesized via a facile chemical method and exfoliated to increase the density of surface-active sites and improve photoluminescence response, were characterized structurally, optically, and morphologically, confirming the desired material properties. The resulting electrochemical sensor exhibited high sensitivity (411 µA µM−1 cm−2) and selectivity for Fe3+, while the nanosheets concurrently demonstrated significant photoluminescence quenching in the presence of Fe3+ (detection limit: 110 nM, range: 200 nM - 1 mM). Computational analysis supported the selective adsorption of Fe3+, highlighting the potential of the combined electrochemical and fluorescence sensing capabilities of exfoliated Bi2O2Se nanosheets for cost-effective, real-time, and portable heavy metal ion detection.