Structure, Interfacial Phenomena, and Optical Properties of Nanoassemblies Based on Ag-In-S/ZnS Semiconductor Quantum Dots and Porphyrin Molecules

The interfacial phenomena and the changes in the spectral properties of the interacting components for self-assembling nanoassemblies formed as a result of electrostatic interactions of positively charged tetra -methylpyridylporphyrins (the free bases) and semiconductor AgInS/ZnS/GSH quantum dots (QD) stabilized by negatively charged glutathione in water (pH 7.5) at 298 K are analyzed on the basis of spectral-luminescence data and the results of quantum-chemical calculations (the MM+ method). Within the framework of the developed size-consistent quantum-chemical 3D model of the QDs a detailed physicochemical sequence of processes occurring on the surface of QDs during interaction with an attached porphyrin molecule, accompanied by the rapid formation of a Zn complex of the porphyrin and its chemisorption on the SH surface of the QDs, is proposed. The obtained results form the basis for a quantitative analysis of the paths and mechanisms of the relaxation of exciton excitation in nanoassemblies of this type.