Effect of relative amount of complexing agents on the properties of Sb2S3 precipitated powders

Powders of Sb2S3 are obtained by a bulk preparation technique using aqueous solutions of antimony trichloride and thioacetamide for two different complexing agents, namely, oxalic acid and tartaric acid. The concentration of solution is kept constant at 0.1 M and only the concentration of complexing agent is varied. The effect of concentration of the complexing agents on the properties of precipitated powder is studied. The powders precipitated using oxalic acid are grey, whereas the powders precipitated using tartaric acid are orange in colour. X-ray diffraction studies reveal that the powders are polycrystalline in nature. Crystallinity using the former acid is relatively higher than that with the latter. It has been observed that the crystallinity goes on decreasing as the concentration of complexing agents increases. Infrared spectroscopy studies indicate the presence of carbon and absorbed water in the powders complexed with oxalic acid. Optical absorption studies show that the direct bandgap energy of the precipitated powders prepared using oxalic acid varies from 1.59 to 1.98 eV and it is found to be higher (1.98 eV) for powder prepared using 0.25 M oxalic acid, while for powders prepared using tartaric acid, it varies from 1.92 to 2.02 eV and is found to be higher (2.02 eV) for the powder prepared using 0.75 M tartaric acid. Electrical resistivity study reveals that the room-temperature electrical resistivity of the powders prepared using oxalic acid is relatively lower ( 10(4)-10(6) Omega cm) than that of tartaric-acid-complexed powders (10(5)-10(7) Omega cm). (C) 1998 Elsevier Science S.A. All rights reserved.