Abstract
M.Sc. (Chemistry)
An aqueous, simple, environmentally friendly synthetic method for the preparation of water-soluble CuS and CdS semiconductor nanoparticles has been developed. Different capping agents with active functional groups (-COOH, -NH and -OH) namely, alanine, glucuronic acid and thioglycolic acid, have been employed in the preparation copper sulfide (CuS) and cadmium sulfide (CdS) semiconductor nanoparticles as capping molecules. These capping agents were explained in Chapter 3 and 4. The reported nanoparticles display good optical and structural properties. The semiconductor nanoparticles were easily synthesized at low temperatures employing low cost materials. In Chapter 3 colloidal methods were used to develop CuS and CdS nanoparticles from metal acetate as a stabilizing
agent at different low temperatures. The effect of temperature on the growth and solubility of nanoparticles was investigated. The absorption spectra of all samples prepared were blue shifted as compared to their bulk materials which signify small particles size. Water-soluble alanine-capped CuS and CdS semiconductor nanoparticles were obtained. The alanine-capped CuS in the form of rods, triangular and spherical like shaped with single crystal phase were successfully attained. Chapter 4 describes the uses of the acids, glucuronic and thioglycolic acids, as capping ligands. The glucuronic acid molecules were found to be the effective ligands to render solubility of the nanoparticles. Solubility tests revealed that both glucuronic acid-capped CuS and CdS nanoparticles were more soluble in
water as compared to thioglycolic acid-capped CuS and CdS nanoparticles. In Chapter 5 sulphonated porphyrins were prepared and explored in combining them with nanoparticles. The results obtained from 1H NMR suggest that the porphyrins were sulphonated. The sulphonated porphyrins were conjugated with the water-soluble nanoparticles and this is described in Chapter 6. The results presented in Chapter 6 are in favour of the formation of nanoparticle-porphyrin complexes.