CdS:Sb thin film photoelectrodes with antimony doping concentration in the range from 0.005-0.5 wt.% have been prepared in an aqueous alkaline medium. Photo-electrochemical cells are then fabricated employing these films as an active photoelectrode and the sulphide/polysulphide redox couple as electrolyte. The electrical and optical properties of these cells have been examined under suitable conditions and evaluated in terms of various cell parameters such as isc, Voc, eta , ff, Rs, Rsh, nd Phi B and Vfb. It has been found that the cell performance is improved significantly after doping and it is optimum at 0.075 wt.% Sb doping level in CdS. The incremental enhancement in the various properties of a cell is explained on the basis of the modified electrical, optical and structural properties of the thin film compositions.

A modified chemical deposition process has been employed for the preparation of antimony trisulfide thin layers onto the plane glass and stainless steel substrates. The as-deposited samples on baking at 120~ are orange-red in color and turn into the dark gray variety on heating to 200~ in an air ambient. The surface topography shows the polycrystal]ine nature of the samples. This is supported by x-ray diffraction observations. The deposits are of n-type with an electron activation energy of 0.80 eV. A n-Sb2SJferrocene-DMSO/C, photoelectrochemical cell was then devised and has been characterized in dark and in light in terms of electrical and optical properties. A short-circuit current (I~) of 0.14 mA/cm 2 and an open-circuit voltage (Vow) equal to 0.155 V are obtained from this cell configuration. The calculated efficiency approached to 0.608%. The other cell parameters have been determined from these studies.

A modified chemical deposition process is employed for the preparation of thin-film (CdS)~-(PbS)I-x composites with 0"2 ~< x ~< 0'8. Cadmium sulphate, lead acetate and thiourea are used as the basic source materials. The electrical conductivity is found to decrease with increasing composition parameter x up to 0"5 and increase for further increase in x. The composites are polycrystalline as is revealed from XRD and microscopic observations and show phases of both cubic and hexagonal CdS, cubic CdO and PbS, and tetragonal PbO and PbO2. Additional peaks of free elemental Cd and S have also been observed. For all the phases no significant variation in lattice parameters with x has been observed. The optical absorption studies show the presence of four well-defined absorption edges at approximately 0"45 eV, 1"05 eV, 1.80eV and 2'35 eV, at the same energies for all x values. The absorption coefficient is of the order of 104cm-1 and mode of band-to-band transition is of the direct type.

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