Development of phase pure Cu2ZnSiSe4 via solid state synthesis for energy applications

In recent years, quaternary diamond-like metal chalcogenide semiconductor nanocrystals have received a lot of attention in solar cell and thermoelectric applications. The optoelectronic properties of quaternary diamond-like structures are influenced by their crystal structure. In this work, a series of experiments have been performed to understand the crystal system of Cu2ZnSiSe4 materials via solid state synthesis, namely mechanosynthesis to get a single phase of quaternary chalcogenide via single step route synthesis. The materials were performed at different milling time to study the single phase compound and phase transformation of the materials. Based on the theory and existing literature, the composition of the materials has been selected as 2:1:1:4 which is the optimum composition for quaternary chalcogenides. Based on the composition, the material properties will be changed. X-ray diffraction (XRD) and Raman spectroscopy were used to analyse the structure and phase purity of Cu2ZnSiSe4 nanoparticles. Field emission scanning electron microscopy (FESEM) and Energy dispersive X-ray spectroscopy (EDS) results showed that the average size of the Cu2ZnSiSe4 particles and the composition of products were close to the stoichiometry of Cu2ZnSiSe4. Optical studies show that Cu2ZnSiSe4 nanocrystals exhibit good, strong optical absorption in the visible region of the electromagnetic spectrum and a 1.12 eV bandgap. Hall measurement shows the bulk property of the materials and it is inferred that the synthesized materials show p-type conductivity in bulk. The obtained compound possesses good structural and optoelectronic behavior and hence could be utilized as effective solar absorber in thin film solar cells.