Novel synthesis and characterization of II-VI group derivative materials including SnS CuInSe2 and Cu2ZnSnS4

Abstract

The objective of this thesis is the synthesis and characterization of the II-VI group solar absorption materials including SnS CuInSe2 (CIS) and Cu2ZnSnS4 (CZTS) We used a hydrothermal solid state reaction and electrospinning processes to prepare these absorption materials In the hydrothermal process we optimized the experimental condition such as reaction time reaction temperature and concentration of the reactant to obtain optimum high purity single phase CZTS powders with P-type conductivity In the low temperature solid state reaction CuInSe2 could be prepared by using CuSe and InSe binary precursors via solid state reaction The as-prepared CuInSe2 films have good thermal stability suitable bandgap value and a good crystallinity chalcopyrite structure with P-type conductivity The results can provide a shortcut to producing CIS thin films for absorption layers In addition polyvinylbutyral/SnS (PVB/SnS) and cellulose acetate/CZTS (CA/CZTS) composite fibers were synthesized through a relatively simple electrospinning process In a typical synthesis SnCl2·2H2O CH4N2S and PVB were dissolved in ethanol under magnetic stirring at room temperature for 2h to obtain a homogenous precursor of PVB/SnS composites CuCl ZnCl SnCl4·5H2O CH4N2S and CA were also dissolved in acetone and DI water under magnetic stirring at room temperature for 2h to obtain a homogenous precursor of CA/CZTS composites Homogeneous precursor solutions of PVB/SnS and CA/CZTS composites were prepared and used immediately for the electrospinning process Finally PVB/SnS and CA/CZTS composites fibers were obtained then transferred to a combustion boat and calcined in the N2 atmosphere to obtain SnS and CZTS mesoporous fibers The SnS and CZTS mesoporous fibers were then characterized using X-ray powder diffraction scanning electron microscopy thermogravimetric analysis and transmission electron microscopy The optical and electrical properties of SnS and CZTS mesoporous fibers were also recorded by UV-Vis absorption spectroscopy and Hall effect measurements respectively The results showed that the synthesized SnS and CZTS mesoporous fibers had a p-type conductivity single phase high crystallinity and a stoichiometric composition with suitable band gap value The as-prepared SnS and CZTS mesoporous fibers are thus a suitable material to achieve visible light absorption in a thin film solar cell As described above we plan to fabricate high quality absorption materials and provide a simple low-cost and low environmental pollution procedure for thin film solar cells by using non-vacuum process

Date of Award	2016 Aug 24
Original language	English
Supervisor	Jiunn-Der Liao (Supervisor)