Thin films of noble-metal-based transition metal dichalcogenides, such as PtSe2, have attracted increasing attention due to their interesting layer-number dependent properties and application potential. While it is difficult to cleave bulk crystals down to mono- and few-layers, a range of growth techniques have been established producing material of varying quality and layer number. However, to date, no reliable high-throughput characterization to assess layer number exists. Here, we use top-down liquid phase exfoliation (LPE) coupled with centrifugation to produce PtSe2 nanosheets of varying sizes and thicknesses with a low degree of basal plane defectiveness. Measurement of the dimensions by statistical atomic force microscopy allows us to quantitatively link information contained in optical spectra to the dimensions. For LPE nanosheets we establish metrics for lateral size and layer number based on extinction spectroscopy. Further, we compare the Raman spectroscopic response of LPE nanosheets with micromechanically exfoliated PtSe2, as well as thin films produced by a range of bottom up techniques. We demonstrate that the Eg 1 peak position and the intensity ratio of the Eg 1/A1g 1 peaks can serve as a robust metric for layer number across all sample types.This will be of importance in future benchmarking of PtSe2 films.

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Atomically thin materials are exhibiting unique physical properties. This work investigates the size dependent nonlinear optical response of black phosphorus nanosheets for nanosecond laser pulses. Material is prepared with the use of Liquid Phase Exfoliation. Experiments are performed using open aperture Z-scan technique at 532 nm wavelength with ND:Yag, 10 Hz ns as laser source. We report that the nonlinear absorption coefficient of black phosphorus is strongly dependent on flake lateral dimension as well as laser intensity.

Long-term stable gas sensors by tiled networks from LPE-PtSe2.

RASSF enzymes act as key apoptosis activators and tumor suppressors, being downregulated in many human cancers, although their exact regulatory roles remain unknown. A key downstream event in the RASSF pathway is the regulation of MST kinases, which are main effectors of RASSF-induced apoptosis. The regulation of MST1/2 includes both homo- and heterodimerization, mediated by helical SARAH domains, though the underlying molecular interaction mechanism is unclear. Here, we study the interactions between RASSF1A, RASSF5, and MST2 SARAH domains by using both atomistic molecular simulation techniques and experiments. We construct and study models of MST2 homodimers and MST2-RASSF SARAH heterodimers, and we identify the factors that control their high molecular stability. In addition, we also analyze both computationally and experimentally the interactions of MST2 SARAH domains with a series of synthetic peptides particularly designed to bind to it, and hope that our approach can be used to address some of the challenging problems in designing new anti-cancer drugs.