Self-sacrificial template directed hydrothermal route to kesterite-Cu2ZnSnS4 microspheres and study of their photo response properties

Abstract

In this work, a self-sacrificial template directed hydrothermal route to synthesize Cu₂ZnSnS₄ (CZTS) 3D-hierarchical microspheres in the presence of citric acid is reported. The phase purity and morphology of the as-synthesized product were optimised. Citric acid plays a key role in reducing the chance of phase segregation and at the same time it helps in the formation of the 3D structure by affecting the crystal growth process. A time dependent growth study of the microspheres has been performed and a possible growth mechanism is proposed. UV-Vis absorption analysis shows that the material has a strong absorption in the visible range with a direct band gap of 1.45 eV. The photoelectric response of the sample has also been studied which shows significant photo current for the sample fabricated into thin films. Thus the as synthesized CZTS microspheres are an optimum candidate for use as an absorber layer in solar cell devices.