ELECTROSTATICALLY CONTROLLED DIFFUSION OF CARBOXYLIC-ACID DERIVATIZEDQ-STATE CDS NANOPARTICLES IN THERMALLY EVAPORATED FATTY AMINE FILMS

The organization of Q-state semiconductor nanoparticles in thin film f orm is an important research problem of today. In this paper, we demon strate that carboxylic acid derivatized Q-state CdS nanoparticles can be incorporated in thermally evaporated fatty amine films through sele ctive electrostatic interaction by simple immersion of the film in the CdS hydrosol. The density of CdS nanoparticles in the amine matrix ca n be modulated by variation of the hydrosol pH. The kinetics of cluste r incorporation has been followed by quartz crystal microgravimetry (Q CM) and the data analyzed in terms of a one-dimensional (1D) Fickian t ype diffusion model. It is found that the 1D diffusion model is an ade quate representation of the cluster incorporation process. An interest ing him thickness and hydrosol pH dependence of the cluster diffusivit y is observed. Fourier transform IR spectroscopy of the thermally evap orated amine films before and after CdS nanoparticle diffusion showed a weak coupling of the clusters with the protonated amine groups as we ll as an increase in the all-trans packing of the hydrocarbon chains a fter cluster incorporation. X-Ray photoelectron spectroscopy (XPS) mea surements were performed on the CdS nanoparticle films for a chemical characterization of the film surface.