Hydrothermally Grown VS2 Nanosheets: A Material for Optical Limiting Applications

The first graphene descendants in 2D materials that sparked intense research activity are transition-metal dichalcogenides, which have a lot of applications because of their band gap. We present a detailed investigation into the structural, morphological, linear, and nonlinear optical properties of hydrothermally grown VS 2 nanostructures by varying the precursor concentration, hydrothermal temperature, and duration of growth. XRD pattern confirms the formation of hexagonal VS 2 nanostructures. The morphological studies were carried out using FESEM, which confirms the nanosheet-like structure of VS 2 samples. The transition from indirect to direct band gap of VS 2 was confirmed by optical studies. From UV–vis absorption spectra, the direct band gap was calculated to be in the range of 1.36 to 1.55 eV. The open aperture Z-scan studies reveal the reverse saturable absorption nature and optical limiting capabilities of VS 2 nanostructures under nanosecond laser pulses at 532 nm wavelength. The results show that these nanostructures exhibit excellent optical limiting behavior, which is attributed to the effects of excited-state absorption. This finding suggests that VS 2 nanostructures could be used as optical limiters against intense laser radiation or as nonlinear optical devices for all-optical switching applications.