Structural and optical properties of SnS2 nanosheets for Opto-electronic devices

Tin disulfide (SnS2) is a promising material for applications in photodetectors, hydroelectric cells, photovoltaics, and energy storage owing to its layered structure, excellent optical and electrical properties, and high chemical stability. In this study, SnS2 nanosheets were fabricated using the sol-gel technique, a method known for its efficiency in producing high-purity nanostructures on a large scale at a reasonable cost. To produce the final SnS2 nanosheets, a precursor solution consisting of Sn and sulfur sources was prepared. This was followed by careful hydrolysis of Tin (IV) chloride pentahydrate with thiourea, forming a gel, which was dried and annealed to form crystalline SnS2 nanosheets. X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, and Photoluminescence spectroscopy (PL) were used to investigate the structural, morphological, chemical-bond, optical and electrical characteristics of the produced SnS2. While TEM and Selected area electron diffraction (SAED) revealed well-ordered nanosheets with high crystallinity and a lattice spacing of 0.58 nm, the XRD investigation verified the production of a pure hexagonal SnS2 phase. UV-Vis spectroscopy estimated a band gap of 2.37 eV. PL spectra showed a prominent emission peak at 699 nm, suggesting a direct bandgap transition suitable for optoelectronic devices. The CIE coordinates of (0.258, 0.286), which fall in the bluish-cyan region of the chromaticity diagram, confirming a bluish emission, suitable for optoelectronic devices. FTIR analysis of sol-gel-synthesized SnS2 confirmed the presence of Sn-S bonds, indicating successful compound formation. According to these estimations, the optical band gap falls within the range appropriate for optoelectronic applications. The Electrical studies demonstrated a carrier concentration of 8.6 × 1015 cm-3 and high mobility of 218 cm2/V.s. A photodetector fabricated using the Ag/SnS₂/ITO-glass heterostructure exhibited excellent photoresponse, with responsivity of 530 mA/W and an external quantum efficiency of 96.9% under 680 nm illumination. These findings establish sol–gel-derived SnS₂ nanosheets as a versatile and efficient material platform for advanced optoelectronic and energy-harvesting devices.