Highly Selective Optical Detection of Fe³⁺ Ions in Aqueous Solution Using Label‐Free Silicon Nanocrystals

Abstract High brightness amine‐terminated silicon nanocrystals (Si NCs) have been utilized in a simple and rapid assay for the highly selective and sensitive detection of Fe³⁺ via quenching of their strong blue luminescence, without the need for analyte‐specific labeling groups. Sensitive detection of Fe³⁺ is successfully demonstrated, with a linear relationship observed between luminescence quenching and Fe³⁺ concentration from 5 × 10⁻⁶ to 900 × 10⁻⁶m and a limit of detection of 1.3 × 10⁻⁶m. The Si NCs show excellent selectivity toward Fe³⁺ ions, with no quenching of the luminescence signal induced by the presence of Fe²⁺ ions, allowing for solution phase discrimination between the ionic species in different charge states.