Highly luminescent thin films from alternating deposition of CdTe nanoparticles and polycations

Thin polymeric films with high concentration of CdTe-nanocrystals are obtained by the self-assembly process of layer-by-layer deposition. Water soluble CdTe particles stabilized by a shell of thioglycolic acid are combined with three different polyelectrolytes: poly(ethylenimine) (PEI), poly(allylamine hydrochloride) (PAH), and poly(diallyldimethylammonium chloride) (PDDA). The film build-up is monitored by means of absorption and fluorescence spectroscopy. The electrostatic adsorption of the particle at the polymer surface is strongly determined by the pH value of the particle solution and the chemical structure of the polymer. Polycations with partially unsaturated nitrogen groups exert strong quenching on the particle fluorescence.