Single-layer MoS2-MoO3-x heterojunction nanosheets with visible-light-sensitive band gap energy and average lateral dimensions of ~70 nm were synthesized by using a two-step combined exfoliation method. The exfoliation was initiated from pristine MoS2, while some sulfur sites in expanded MoS2 sheets during exfoliating were substituted by ambient non-thermal oxygen, resulting in formation of α-MoO3-x crystalline domains. The morphological features, crystalline structure, phase formation, number of layers, and optical properties of the MoS2-MoO3-x nanosheets were determined by atomic force microscopy; X-ray diffraction; field emission electron microscopy; transmission electron microscopy; and Raman, UV–visible–NIR, diffuse transmittance, and photoluminescence spectroscopies. The produced α-MoO3-x domains displayed a narrower indirect band gap energy (~1.95 eV) than that of stoichiometric MoO3 (~3 eV), and a broad light absorption range from visible to near-infrared region can act as a plasmonic material facilitating the separation of the photoinduced carriers and enhancing the photocatalytic activity of the MoS2 domain, having ~1.75(2.16) eV indirect (direct) band gap energy. In this regard, the MoS2-MoO3-x heterojunction nanosheets showed single-layer-based excitation-dependent luminescence emissions and visible-light-induced photocatalytic features, at the same time. This study can contribute to promising applications of sheet-like nanomaterials for purposes requiring simultaneous photoluminescence and photocatalytic features, such as in-vivo monitoring and targeting.

A remote controllable working graphite nanostructured swimmer based on a graphene jet nanomotor has been demonstrated for the first time. Graphite particles with pyramidal-like morphologies were fabricated by the creation of suitable defects in wide high-purity graphite flakes followed by a severe sonication. The particles were able to be self-exfoliated in water after Na intercalation between the graphene constituents. The self-exfoliation resulted in jet ejection of graphene flakes from the end of the swimmers (with speeds as high as ∼7000 m/s), producing a driving force (at least ∼0.7 L (pN) where L (μm) is swimmer size) and consequently the motion of the swimmer (with average speed of ∼17-40 μm/s). The jet ejection of the graphene flakes was assigned to the explosion of H2 nanobubbles produced between the Na intercalated flakes. The direction of motion of the swimmers equipped with TiO2 nanoparticles (NPs) can be controlled by applying a magnetic field in the presence of UV irradiation (higher UV intensity, lower radius of rotation). In fact, the negative surface charge of the graphene flakes of the swimmers increased by UV irradiation due to transferring the photoexcited electrons of TiO2 NPs into the flakes. Because of higher production of H2 nanobubbles under UV irradiation, the speed of swimmers exposed to UV light significantly increased. In contrast, UV irradiation with various intensities could not affect total distance traversed by the self-exfoliated swimmers having the same initial sizes. These confirmed the mass ejection mechanism for motion of the swimmers. The self-exfoliation of swimmers (and so their motion) occurred only in water (and not, e.g., in organic solutions). Such swimmers promise the design of remote controllable nanovehicles with the capability of initiating and/or improving their operations in response to environmental changes in order to realize broad ranges of versatile and fantastic nanotechnology-based applications.

Ultrathin MoS 2 −MoO 3−x heterojunction nanosheets with unique features were introduced as biocompatible, non-cytotoxic, and visible light-sensitive stimulator layers for the controlled differentiation of human neural progenitor cells (hNPCs) into nervous lineages. hNPC differentiation was also investigated on reduced graphene oxide (rGO)-containing scaffolds, that is, rGO and rGO/MoS 2 −MoO 3−x nanosheets. In darkness, hNPC differentiation into neurons increased on MoS 2 − MoO 3−x by a factor of 2.7 due to the excellent biophysical cues and further increased on rGO/MoS 2 −MoO 3−x by a factor of 4.4 due to a synergistic effect induced by the rGO. The MoO 3−x domains with antioxidant activity and LSPR absorption induced p-type doping in MoS 2 −MoO 3−x . Under photostimulation, the hNPCs on the MoS 2 −MoO 3−x exhibited higher differentiation into glial cells by a factor of 1.4, and the decrease in photo-electron current to hNPCs due to the induction of more p-type doping in the MoS 2 − MoO 3−x . While the increase in neuronal differentiation of hNPCs on rGO/MoS 2 −MoO 3−x by a factor of 1.8 was ascribed to the presence of rGO as an ultrafast electron transferor which quickly transferred photogenerated electrons to hNPCs before their transfer to free radicals, these results demonstrated the promising potential of MoS 2 -based scaffolds for applying in the controllable repair and/or regeneration of diseases/disorders related to the nervous system.