Visual and trap emission spectrometric detections of Ag (I) ion with mesoporous ZnO/CdS@SiO2 core/shell nanocomposites

A new method for the preparation of mesoporous ZnO/CdS@SiO2 core/shell nanostructure (CSN) has been developed. The mesoporous silica shells allow Ag+ to enter into the interior of the nanostructures to contact with ZnO/CdS core, accordingly causes the quenching of its band edge emission (475 nm) along with a simultaneous enhancement of red emission at around 595 nm. So, a novel visual fluorescence detection strategy for Ag+ ion is proposed based on a common core/shell Quantum dots nanostructure. Under optimal conditions, the enhanced fluorescence intensity at 595 nm increased linearly with the concentration of Ag+ ion ranging from 0.03 μM to 0.24 μM with a detection limit (3σ) of 3.3 nM.

A novel type of mesoporous ZnO/CdS@SiO2 core/shell nanostructures was prepared with a simple method, which was successfully applied to the visual fluorescence detection of Ag+ in an aqueous medium based on the enhanced trap emission and the variations of dual-emission fluorescence features of ZnO/CdS QDs core.Figure optionsDownload as PowerPoint slideHighlights
► A novel type of ZnO/CdS core/shell QDs was prepared.
► A simple method for encapsulating water-soluble ZnO/CdS QDs into mesoporous SiO2 shell.
► The enhanced trap emission of ZnO QDs core greatly improves detection selectivity.
► High sensitivity and selectivity for visual fluorescence detection of Ag (I).