Quantum two-dimensional (2D) materials discovered in the early 21st century have outsmarted existing nanomaterials in various frontiers of applications. Among the preparation of 2D materials, molecular beam epitaxy, atomic layer deposition, and chemical vapor deposition are nonscalable costly methods, whereas sonochemical and Hummer's exfoliation methods provide functionalized sheets. Conversely, ultrafast liquid-phase laser processing promises quick delivery of defect-free 2D quantum materials. We report photoexfoliation synthesis of atomic graphene layers, boron nitride (BN), and molybdenum disulfide (MoS 2 ) by the intense KrF laser irradiation into aqueous dispersions of parent material powders in DMF taken in quartz beakers. The number of atomic layers and the lateral size of the sheets gradually decrease with an increase in the laser irradiation duration. Also, the laser fluence becomes the critical control parameter of the lateral size and the number of layers. The average lateral size shrinks from ∼400 nm at 1.5 J/cm 2 to 20−30 nm at 4 J/cm 2 , which accompanies a surge in the ratio of sheets with fewer layers. We correlate the laser processing parameters with the sample size and analyze the molecule-atom-scale interactions. Simulation and DFT calculations suggest the mild out-of-plane thermal expansion of atomic layers followed by solvent intercalation stretches interlayer distance to ∼6.68 Å and thereby lowers the activation energy of exfoliation. The optimum photon fluence at the solvent-assisted condition reduces the activation barrier, enabling us to synthesize 2D crystals in the solution phase. Photoexfoliation synthesis of pure crystals of 2D materials can be promising for next-generation electronic devices.

Most of the known two-dimensional materials lack a suitable wide-bandgap, and hydrogenation can be effectively utilized to tune the bandgap of some 2D materials.

Transition metal dichalcogenides (TMDs) offer superior properties over conventional materials in many areas such as in electronic devices. In recent years, TMDs have been shown to display a phase switching mechanism under the application of external mechanical strain, making them exciting candidates for phase change transistors. Molybdenum ditelluride (MoTe2) is one such material that has been engineered as a strain-based phase change transistor. In this work, we explore various aspects of the mechanical properties of this material by a suite of computational and experimental approaches. Firstly, we present parameterization of an interatomic potential for modeling monolayer as well as multilayered MoTe2 films. For generating the empirical potential parameter set, we fit results from Density Functional Theory calculations using a random search algorithm called particle swarm optimization. The potential closely predicts structural properties, elastic constants, and vibrational frequencies of MoTe2 indicating a reliable fit. Our simulated mechanical response matches earlier larger scale experimental nanoindentation results with excellent prediction of fracture points. Simulation of uniaxial tensile deformation by Molecular Dynamics shows the complete non-linear stress-strain response up to failure. Mechanical behavior, including failure properties, exhibits directional anisotropy due to the variation of bond alignments with crystal orientation. Furthermore, we show the deterioration of mechanical properties with increasing temperature. Finally, we present computational and experimental evidence of an extended c-axis strain transfer length in MoTe2 compared to TMDs with smaller chalcogen atoms.

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