Highly Selective Optical Detection of Fe 3+ 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 Fe 3+ via quenching of their strong blue luminescence, without the need for analyte-specific labeling groups. Sensitive detection of Fe 3+ is successfully demonstrated, with a linear relationship observed between luminescence quenching and Fe 3+ concentration from 5 × 10 −6 to 900 × 10 −6 m and a limit of detection of 1.3 × 10 −6 m. The Si NCs show excellent selectivity toward Fe 3+ ions, with no quenching of the luminescence signal induced by the presence of Fe 2+ ions, allowing for solution phase discrimination between the ionic species in different charge states.