Colloidal Second Near-infrared-emitting Mn-doped Ag2S Quantum Dots

Abstract

Incorporation of transition metal dopants within a semiconductor nanocrystal has a tremendous effect on the optical and magnetic properties of the semiconductor nanocrystals. Herein, we report on a novel synthesis of second near-infrared-emitting photoluminescent Mn2+-doped Ag2S quantum dots via co-pyrolysis of silver and manganese single-source precursors. The Mn2+ doping level was flexibly tuned in Ag2S quantum dots, which was confirmed by elemental analysis and electron paramagnetic resonance spectroscopy. The Mn2+ doping induced negligible change in the pristine monoclinic acanthite Ag2S crystal structure but significantly decreased the photoluminescent intensity. Mn2+-doped Ag2S QDs exhibit second near-infrared emission and ferromagnetic ordering, which show the potential applicability for multimodal fluorescence/MRI probes.