Transition metal dichalcogenide nanospheres for high-refractive-index nanophotonics and biomedical theranostics

Abstract

Recent developments in the area of resonant dielectric nanostructures has created attractive opportunities for the concentrating and manipulating light at the nanoscale and the establishment of new exciting field of all-dielectric nanophotonics. Transition metal dichalcogenides (TMDCs) with nanopatterned surfaces are especially promising for these tasks. Still, the fabrication of these structures requires sophisticated lithographic processes, drastically complicating application prospects. To bridge this gap and broaden the application scope of TMDC nanomaterials, we report here femtosecond laser-ablative fabrication of water-dispersed spherical TMDC (MoS2 and WS2) nanoparticles (NPs) of variable size (5 - 250 nm). Such nanoparticles demonstrate exciting optical and electronic properties inherited from TMDC crystals, due to preserved crystalline structure, which offers a unique combination of pronounced excitonic response and high refractive index value, making possible a strong concentration of electromagnetic field in the nanoparticles. Furthermore, such nanoparticles offer additional tunability due to hybridization between the Mie and excitonic resonances. Such properties bring to life a number of nontrivial effects, including enhanced photoabsorption and photothermal conversion. As an illustration, we demonstrate that the nanoparticles exhibit a very strong photothermal response, much exceeding that of conventional dielectric nanoresonators based on Si. Being in a mobile colloidal state and exhibiting superior optical properties compared to other dielectric resonant structures, the synthesized TMDC nanoparticles offer opportunities for the development of next-generation nanophotonic and nanotheranostic platforms, including photothermal therapy and multimodal bioimaging.

18 pages, 4 figures

References in corpus (5)

• Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material
• Laser-thinning of MoS2: on demand generation of a single-layer semiconductor
• Imaging exciton-polariton transport in MoSe2 waveguides
• Nonlinear imaging with all-dielectric metasurfaces
• Topological phase singularities in atomically thin high-refractive-index materials

Cited by in corpus (4)

• Hybrid Au-Si microspheres produced by laser ablation in liquid (LAL) for temperature-feedback optical nano-sensing and anti-counterfeit labeling
• Exciton Assisted Deeply Subwavelength Nano-Photonics
• High-refractive index and mechanically cleavable non-van der Waals InGaS3
• Tunable Nanostructuring for van der Waals Materials