Excitation Transfer in Hybrid Nanostructures of Colloidal Ag2S/TGA Quantum Dots and Indocyanine Green J-Aggregates

J Fluoresc. 2020 May;30(3):581-589. doi: 10.1007/s10895-020-02521-2. Epub 2020 Mar 31.

Abstract

The regularities of the electron excitations exchange in hybrid associates of colloidal Ag2S quantum dots, passivated with thioglycolic acid (Ag2S/TGA QDs) with an average size of 2.2 and 3.7 nm with Indocyanine Green J-aggregates (ICG) were studied in this work by methods of absorption and luminescence spectroscopy. It was shown that IR luminescence sensitization of Ag2S/TGA QDs with an average size of 3.7 nm in the region of 1040 nm is possible due to non-radiative resonance energy transfer from Ag2S/TGA QDs with an average size of 2.2 nm and luminescence peak at 900 nm using ICG J-aggregate as an exciton bridge. The sensitization efficiency is 0.33. This technique provides a transition from the first therapeutic window (NIR-I, 700-950 nm) to the second (NIR-II, 1000-1700 nm). It can allow high to increase the imaging in vivo resolution.

Keywords: Hybrid associate; Indocyanine green; J-aggregates; Luminescence properties; Non-radiative resonance energy transfer (FRET); Silver sulfide quantum dots.