Deposition,structure and properties of polyamide-CdSe-CdS composite material using sorption-diffusion method

摘要

Polyamide (PA) incorporated CdSe-CdS films were deposited using sorption-diffusion method. A single precursor - K_2SeS_2O_6 was used as both sulfur and selenium source. In aqueous solution, SeS_2O_6~(2-) diffused into the polymer where it reacted with Cd~(2+) ions to form cadmium chalcogenide particles. Crys-tallinity of the composite material was analyzed via XRD and both CdSe and CdS were detected within the material at all deposition conditions of temperature and SeS_2O_6~(2-) - chalcogenization - exposure time. A complex surface speciation was obtained using XPS analysis. Formation of the protonated amide species was observed in combination with the adsorbed SO_4~(2-) on the surface of the polymer confirming that SeS_2O_6~(2-) and its decomposition products hydrolyzed to form cadmium chalcogenides and H_2SO_4. A significant red shift in UV-vis spectrum was observed with the increasing chalcogenization time of PA, whereas Cd~(2+) solution temperature had very little effect on the apparent thickness and the optical properties of the composite materials. SEM surface analysis revealed sub-micron particles deposited on top of the PA-CdSe-CdS composite materials in continuous overlapping films, showing a possible dual crystal growth mechanism.