Metal acetate based synthesis of small-sized Cu2ZnSnS4 nanocrystals: effect of injection temperature and synthesis time

Abstract

We report the colloidal synthesis of small-sized Cu₂ZnSnS₄ (CZTS) nanocrystals (NCs) via a hot-injection method using zinc and tin acetates in combination with copper acetylacetonate as metal precursors. A systematic investigation of the influence of the injection temperature in the range from 190 °C to 300 °C on the size distribution, composition and phase purity of CZTS nanocrystals has been performed. It has been found that temperature plays the key role in changing of the metal sources reactivity and influences the final composition of the nanocrystals. The mechanism of nanocrystal formation has been investigated by Raman spectroscopy of aliquots of their solutions. It starts from the formation of a Cu_2−xS phase as a core followed by the incorporation of Zn²⁺ and Sn⁴⁺ atoms into its structure regardless of injection temperature.