Coupling solvent-mediated modulations with the morphological, optical, and antimicrobial attributes of solvothermally synthesized multifunctional Cu2ZnSnS4 nanoparticles

In this study, two distinct reaction media- water (CZTS1) and ethylene glycol (EG) (CZTS2) were used to synthesize nanocrystalline Cu2ZnSnS4 (CZTS) samples using the facile solvothermal method. X-ray diffraction (XRD) analysis indicated the presence of a tetragonal kesterite phase in both samples with CZTS2 exhibiting broader peaks and smaller crystallite size (6.04 nm) compared to CZTS1 (8.78 nm). Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX) analysis revealed the superior surface morphology and better stoichiometric composition of CZTS2 nanoparticles. In terms of optical properties, the direct bandgap values of CZTS1 and CZTS2 show variation from 1.45 eV to 1.50 eV, as determined from the Tauc plot. Furthermore, the antimicrobial assay of samples was identified by their zone of inhibition of a bacterial (Bacillus subtilis) and a fungal (Tilletia indica) strain demonstrating CZTS1 exhibited more robust antimicrobial activity compared to CZTS2 suggesting its potential in agriculture, food safety, and healthcare.