IR Luminescence of Polyfunctional Associates of Indocianine Green and Ag-=SUB=-2-=/SUB=-S Quantum Dots-=SUP=-*-=/SUP=-

Abstract

In this work, manifestations of IR luminescence sensitization of Indocyanine Green during conjugation with colloidal Ag2S quantum dots with average size of 2.2 and 3.7 nm, passivated with thioglycolic acid molecules (Ag2S/TGA QDs) are studied using absorption and luminescence techniques. The possibility of enhancing luminescence in the dye monomer band (820 nm) under excitation of 660 nm by a factor of 6 in the presence of Ag2S/TGA QDs (2.2 nm) due to a decrease in the dye polymethine chain due movement via coordination interaction with quantum dots was demonstrated. The way to switch-over from the first therapeutic window of biological tissue transparency (NIR-I, 700-950 nm) to the second (NIR-II, 1000-1700 nm), based on sensitization of IR luminescence of Ag2S/TGA QDs with an average size of 3.7 nm in the region of 1040 nm due to of resonance non-radiative transfer of excitation energy from Ag2S/TGA (2.2 nm) QDs at 900 nm to Ag2S/TGA QDs (3.7 nm) via the J-aggregate of ICG dye, which acts as an exciton bridge.