Synthesis of Cu2ZnSnS4 Nanocrystallines by a Hydrothermal Route

Cu2ZnSnS4 is an ideal candidate absorber material for thin film solar cells with an optimal band-gap for a single junction photovoltaic device of 1.4-1.5 eV, high absorption coefficient (>10(4) cm(-1)), and abundant elemental components. In this paper, Cu2ZnSnS4 nanocrystallines have been successfully synthesized by a hydrothermal method using CuCl, ZnCl2, SnCl4 center dot 5H(2)O and (NH2)(2)CS as reaction reagents for the first time. The as-grown product was characterized by X-ray powder diffraction, transmission electron microscopy, high-resolution transmission electron microscopy and selected-area electron diffraction. The results confirm that the product was polycrystalline Cu2ZnSnS4 nanoparticles with the diameter of 5-7 nm. The effect of the reaction temperature and time on the formation of the Cu2ZnSnS4 nanocrystallines was discussed. The band-gap of Cu2ZnSnS4 nanocrystallines was estimated to be 1.70 eV via ultraviolet-visible (UV-vis) absorption spectrum of Cu2ZnSnS4 nanocrystallines. Raman spectrum of Cu2ZnSnS4 nanocrystallines had about 8 cm(-1) red-shift in comparison with that of the responding bulk counterpart. (C) 2011 The Japan Society of Applied Physics