Binary and ternary metal chalcogenides for sustainable and inexpensive solar energy generation

Abstract

Binary and ternary metal chalcogenide semiconductors like antimony, copper, iron and cobalt sulfide and their alloys have a wide range of applications especially in the solar cells field. These semiconducting materials offer earth-abundant, low toxic and cheap alternatives for photovoltaic devices fabrications, instead of commonly used highly toxic and expensive metals (such as Cd or Pb, Te and In). In this study, diethyldithiocarbamate complexes M(S2CNEt2)n (where M= Sb (III), Cu (II), Fe (III), and Co (II)) were synthesized as molecular precursors for the preparation of binary and ternary metal sulfide materials. The samples Sb2-2xM2xS3 (0 ≤ x ≤ 1) were prepared by solvent less synthesis and AACVD method by considering excellent stoichiometric control to develop thin films and nanoparticles. This work is divided into six chapters, in which the first chapter provides a brief summary of the chalcogenide-based semiconducting materials and the different approaches for the synthesis of metal chalcogenide thin films and nanoparticles. This chapter also provides a complete literature review of all the single source precursors used until the present for the preparation of antimony as well as its ternary chalcogenide materials. The second chapter gave a brief description of the experimental techniques used thorough out this work. The third chapter, tested the efficacy of iron into Sb2S3 via the solventless thermolysis method at 450 °C. Sb (III), and Fe (III) complexes of diethyldithiocarbamate have been used as molecular precursors for the synthesis of Sb2-2xFe2xS3 (0 ≤ x ≤ 1) in entire range with excellent stoichiometric control. The effect of the addition of Fe into the Sb2S3 on the chemical composition morphology and band gap was investigated. Magnetic properties of the nanomaterials prepared were also studied. The fourth chapter, describes the formation of ternary Sb2-2xCu2xS3 (0 ≤ x ≤ 1) solid solution in entire range with excellent stoichiometric control via solventless thermolysis using Sb (III) and Cu (II) diethyldithiocarbamate as molecular precursors. The structural analysis shows that copper was effectively introduced as a solid solution into antimony sulfide. Thin films were also deposited on glass substrates using AACVD. A single-phase pure chalcostibite (CuSbS2) and tetrahedrite (Cu12Sb4S13) were obtained using the solventless methods and phase of the ternary material changes from chalcostibite (CuSbS2) and fematinite (Cu3SbS4) at a low Cu : Sb ratio to tetrahedrite (Cu12Sb4S13) at a high Cu : Sb ratio using the AACVD method. The fifth chapter studied the incorporation of cobalt into Sb2S3 using the solvent less thermolysis method. Sb (III), and Co (II) complexes of diethyldithiocarbamate have been applied as molecular precursors for the synthesis of Sb2-2xCo2xS3 (0 ≤ x ≤ 1) solid materials. The effect of the chemical composition on morphology and magnetic properties of the materials were investigated. In addition to the solvent less synthesis, AACVD method was also used for the deposition of pure CoSbS thin films and the effect of the chemical composition on band gap were also studied. Chapter six provides a brief conclusion of all the experimental chapters and the future work plan.

Date of Award	31 Dec 2022
Original language	English
Awarding Institution	The University of Manchester
Supervisor	David Lewis (Supervisor) & Eric Prestat (Supervisor)