Computer Simulation of the Adsorption of meso-Tetra(3-Pyridyl)porphyrin Dye on the Surface of Colloidal CdSe Quantum Dots

A classical all-atom molecular dynamics simulation has been used to study the adsorption of mesotetra( 3-pyridyl)porphyrin dye on colloidal quantum dots of cadmium selenide. The competition between dye molecules and ligands covering the quantum dots has been investigated by the examples of trioctylphosphine, trioctylphosphine oxide, octadecylphosphonic acid, and hexadecylamine. It has been shown that the dye is strongly retained by the surface and is not washed out with a solvent either from a free surface or in the presence of trioctylphosphine in the shell. The strength of the adsorption of the dye is equal to that of trioctylphosphine. At the same time, it gives up its place on the surface to stronger ligands, octadecylphosphonic acid and hexadecylamine.