Photothermal properties of two-dimensional molybdenum disulfide (MoS2) with nanoflower and nanosheet morphology

PEGylated MoS2 nanoflower (MoS2-NF) and nanosheet (MoS2-NS) are synthesized through a one-pot hydrothermal method as photo absorbing agent (PAA). It is found that employing different thiol precursors result in distinct morphologies. The products are structurally, chemically, and morphologically characterized. Electron microscopy demonstrates the formation of sheet and flower morphologies of MoS2. Fourier transform infrared (FTIR) and thermal gravimetric (TGA) analysis confirm the PEGylation of MoS2 nanostructures. Raman and X-ray photoelectron spectroscopy (XPS) confirm the formation of 1T/2H structure of both samples. MoS2-NS demonstrates higher NIR absorption than MoS2-NF with a mass extinction coefficient of 19.06 and 5.09 L/g.cm, respectively. The photothermal conversion efficiency (η) of MoS2-NF and MoS2-NS is 13.77% and 25.68%, respectively which can be due to the higher 1T to 2H ratio of MoS2-NS. Finally, MoS2-NS has significantly higher photo-to-heat conversion ability in comparison with MoS2-NF which makes it more suitable as PAA for photothermal therapy of tumors.