Investigations on the interaction of water-soluble semiconductor polymer with thioglycolic acid (TGA) capped CdTe quantum dots

Abstract

Studies of nanocomposites produced by the association of quantum dots (QDs) and polymers, in general, use the nanocrystals as the energy's donor and the polymer's molecules as acceptors. The production of nanocomposites in which a water-soluble polymer is the energy donor species and the quantum dots the acceptors species is particularly difficult due to low luminescence quantum yield and low fluorescence lifetimes of these molecules when compared to the QDs. In this work, we associated colloidal CdTe QDs stabilized with thioglycolic acid (TGA) with water-soluble semiconductor luminescent polymer Poly{[2,5-bis(2-(N,N-diethylamino)ethoxy)-1,4-phenylene]-alt-1,4-phenylene} (PPE-DBE) to produce nanocomposites that favors the polymers as donors and QDs as acceptors. We characterized the composites by absorption, static fluorescence, and dynamic fluorescence. Our results showed the intensification of the QDs emission and its quantum yield on the nanocomposite and the decrease of the polymer lifetime. Thus, we verified the occurrence of energy transfer from the polymer to the quantum dots, especially for samples which the ratio of PPP-DBE monomers per number of QDs in solution is approximately 465, achieving an increase of 11.34% on the QDs' fluorescence quantum yield.