A Facile and TGA Free Hydrothermal Synthesis of SnS Nanoparticles

Abstract

In this paper, we employed a simple and cost-effective thioglycolic acid (TGA) free hydrothermal method, based on thiourea hydrolysis of stannous chloride dihydrate [SnCl2.2H2O] at 160[Formula: see text]C–190[Formula: see text]C for 6[Formula: see text]h, for the synthesis of SnS nanoparticles. The effect of hydrothermal autoclave reaction temperature on various properties of SnS nanoparticles have been examined at length using X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy attached with EDAX (FE-SEM), transmission electron microscopy (TEM) and ultraviolet-visible (UV-Vis) spectroscopy. The results suggest that the crystallization of orthorhombic SnS nanoparticles, with size varying from 3[Formula: see text]nm to 5[Formula: see text]nm, formed at R[Formula: see text]C. Further, the formation of SnS phase was confirmed by an IR Sn-S characteristic bands around 2350[Formula: see text]cm[Formula: see text], 1041[Formula: see text]cm[Formula: see text] and 570[Formula: see text]cm[Formula: see text], and four distinguished Raman peaks at 95[Formula: see text]cm[Formula: see text], 160[Formula: see text]cm[Formula: see text], 189[Formula: see text]cm[Formula: see text] and 220[Formula: see text]cm[Formula: see text]. The mechanism for the formation of SnS nanoparticles have been proposed and discussed. The SnS nanoparticles have exhibited reaction temperature dependent morphological features like nanoflowers, nanoflakes, spherical nanoparticles and nanogranules. The absorbance studies indicated both strong direct and weak indirect allowed transitions for SnS nanoparticles and the associated band gaps were found to be 1.5[Formula: see text]eV and 1.19[Formula: see text]eV, respectively. The dual band gap combination of SnS would favor strong direct absorption of carriers and improved minority carrier life time due to indirect nature, which means the grown particles are suitable for ideal absorber material for solar cell applications.