PREPARATION OF SIZE-QUANTIZED CDS AND ZNS PARTICLES IN SOLID-LIQUID ADSORPTION LAYER ON HYDROPHOBIC LAYER SILICATES

Subcolloidal (7-10 nm) CdS and ZnS semiconductors were prepared in sus pensions with ethanol-cyclohexane or methanol-cyclohexane in the adsor ption layer or interlamellar space on hydrophobic (HDP-montmorillonite ) clay mineral surface. This adsorption Layer, and the interlamellar s pace between the silicate lamellae was used as a nanophase reactor for the in situ generation of size-quantized cadmium sulfide and zinc sul fide semiconductor particles from cadmium (or zinc) acetate and equiva lent amounts of H2S. The volumes of the nanophase reactor in ethanol-c ydohexane at a given mixture composition were determined, by adsorptio n excess isotherm and X-ray diffraction measurements. As expected, sma ller sized semiconductor particles were generated in the smaller nanop hase reactor, provided by the methanol-rich adsorption layer. Further reduction of semiconductor partides was accomplished by decreasing the concentration of their parent ions in the nanophase reactor. Incorpor ation of semiconductor nanocrystallites into HDP-montmorillonite manif ested itself in increased yield stess and the structure building of th e suspension. Information on the fractal dimensions of the semiconduct or-clay organo-complex suspensions and on the radius of gyration of th e nanoparticles was obtained by small-angle X-ray scattering (SAXS) me asurements. The existence of nanoparticles on the hydrophobic montmori llonite was established by TEM and absorption spectrophotometric metho ds.