Swift Morphosynthesis of Hierarchical Nanostructures of CdS via Microwave-Induced Semisolvothermal Route

Abstract

For the swift generation of hierarchical nanostructures of CdS, we propose herein a docile microwave-induced semi-solvothermal reaction (i.e., involving simultaneous usage of nonaqueous and aqueous solvents) between cadmium acetate and thiourea in binary solution of diethylenetriamine and deionized water. Typically, such microwave-assisted reaction was accomplished within 5 minutes as against 12 h required in conventional approach. The resultant products were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis by X-rays, laser Raman spectroscopy and photoluminescence spectroscopy. X-ray diffraction data indicates occurrence of hexagonal CdS with strong (002) preferred orientation. SEM images reveal formation of solvent-ratio dependent complex morphological (i.e., hierarchical) features both at the microscale and nanoscale. Fine-scale microstructure examination by TEM discloses formation of entangled nanorods, nano(potato)sticks, nanoflowers etc. Elemental analysis facility (equipped with TEM) suggests presence of Cd rich product. Raman spectroscopy shows the fundamental and overtone bands pertaining to hexagonal CdS with remarkable enhancement in relative intensities of such bands in case of sample corresponding to diethylenetriamine(DETA)/deionized water(DI) volume ratio of 6:1. Room temperature photoluminescence spectra mainly reveal broad asymmetric emission background composed of classical band edge and trap-induced emission in CdS.