Synthesis of Selected Binary, Ternary and Quaternary Metal Chalcogenides Nanomaterials from Single Source Precursors
Abstract
Metal sulfides are important versatile materials applicable in numerous fields such as electronic and optical devices. Among different synthetic routes, the use of single source precursors is advantageous as they are equally suitable for synthesis of nanomaterials as well as for deposition of thin films. Likewise, due to the presence of preformed bonds between the metal and chalcogenide atoms, there are better chances of controlling the phase, shape and the stoichiometry of the product. In this study, we explore the potential of single source precursors in the synthesis of various technologically important binary, ternary and quaternary materials via scalable and cost effective synthetic routes.
In this work, the synthesis of a range of lead(II) alkyl xanthates and novel lead(II) heterocycle- dithocarbamate complexes was carried out, and their spectroscopic characterisation and crystal structures are described. Using solvent-less and spray-coating pyrolysis techniques, PbS nanoparticles and thin films were produced at low temperature. The effect of the precursor and the techniques used, on fabrication of thin films and nanoparticles were studied through p-XRD, Raman spectroscopy, SEM and EDX analysis. In the next phase of this work, the ternary material, AgSbS2, was produced from a stoichiometric mixture of silver(I) xanthate and antimony(III) xanthate, and their spectroscopic characterisation and thermal decomposition was reported. The mixture of complexes yielded AgSbS2 with excellent control of stoichiometry by using the solvent-less and spin-coating methods. The products were characterised using several techniques, which included, p-XRD, Raman spectroscopy, SEM, and EDX analysis to study the effects of synthetic route’s temperatures and their electrical properties. AgSbS2 (cuboargyrite) has important ferroelectric, thermoelectric and non-linear optical properties and this is the first report of its synthesis from SSPs.
Finally, a series of metal (Cu, Pb and Sb) dithiocarbamate complexes were synthesized and their spectroscopic characterisation and thermal decomposition are reported. These were used to produce the solar absorber material CuPbSbS3 bournonite (CLAS), which was successfully synthesised via two techniques i.e. solvent-less and spray coating pyrolysis. The samples of powder and thin films were characterised using several characterisation techniques including p-XRD, Raman and UV-vis spectroscopy, SEM and EDX analysis. This is also the first example of use of single molecular precursor to prepare CLAS nanomaterials and thin films.