Preparation and Characterization of Cu2ZnSnS4 Nanocrystals and Thin Films

Abstract

The Cu 2 ZnSnS4(CZTS) nanocrystallites were synthesized by hot injection method with starting materials of copper(II) acetylacetonate [Cu(AcAc)2 ], zinc acetate [Zn(CH3 COO)2 ·2H2 O], tin(II) chloride dehydrate [SnCl2 ·2H2 O], elemental sulfur(S) and dodecanethiol. Then CZTS thin films were prepared by spin coating method. The crystallographic structure, morphology, chemical composition and optical properties of CZTS nanocrystallites and their thin films were characterized by X-ray diffraction(XRD), Raman spectrum(RS), transmission electron microscopy(TEM), scanning electron microscope(SEM) with energy dispersive X-Ray spectroscopy(EDS) and UV-Vis transmittance spectroscopy. The influence of injection temperature on the crystallographic structure, morphology, grain size and chemical composition of CZTS nanocrystallites, and the influence of annealing time on the crystallographic, morphology, chemical composition and optical properties of CZTS thin films were investigated respectively. The results show that the CZTS nanocrystallites synthesized at 180 ℃ were consisted of single phase kesterite with an average grain size 18 nm, while the CZTS thin film after annealing at 500℃ for 2h exhibits an absorption coefficient of 104 cm-1 for the visible light and an optical band gap of 1.45 eV.