Microwave-assisted synthesis of Cu2ZnSnS4 and Cu2Zn0.5Ni0.5SnS4 nanoparticles for thin-film solar cells

Abstract

Quaternary chalcogenides doped with transition metals are currently being investigated due to their low toxicity and abundance in nature. These systems are especially well suited for thin-film solar cells applications due to their abundance in nature. In this study, we used the microwave-assisted solvothermal method to synthesize p-type quaternary semiconducting nanomaterials Cu₂ZnSnS₄ and Cu₂Zn_0.5Ni_0.5SnS₄ by using one-pot microwave-assisted solvothermal reactions which is treated at 180 – 200 °C (900W power) for 20 min in inside a domestic microwave oven. It was found that a wide range of structural parameters in the synthesized material could be characterized using X-ray diffraction methods, Raman spectral analysis, scanning electron microscopes (FESEM), energy-dispersive spectroscopy (EDS), transmission electron microscope (TEM), and UV–Vis spectrophotometers. It was found that the prepared material exhibited a kesterite crystal structure with crystallite sizes ranging from 20 to 40 nm. FESEM and TEM analysis exposes the morphological features and EDS analysis confirms stoichiometric ratio of the prepared nanomaterials. The optical absorption measurements showed that the nanostructures prepared had band gaps ranging from 1.58 eV to 1.45 eV, according to the optical absorption analysis. In order to finish the thin-film solar cell production process and to further investigate the properties of the CZTS and CZNTS layers, the following additional layers were deposited: CdS with chemical bath deposition; ZnO-Al with RF magnetron deposition; and, finally, Ni-Ag fingers as the front contact. Measurements were made of the thin-film solar cells' efficiency and properties, such as CZTS—3.10% and CZNTS—5.873%, respectively. The prepared materials and properties suggested that these two quaternary chalcogenide systems could be suitable low-cost solar absorber material for thin-film solar cells (TFSC) applications.