Direct synthesis of either 2H-MoS2 or α-MoO3 is made possible by thermolysis of the same single source precursor in either argon or air at moderate temperatures.

Black phosphorus is a two-dimensional material that has potential applications in energy storage, high frequency electronics and sensing, yet it suffers from instability in oxygenated and/or aqueous systems. Here we present the use of a polymeric stabilizer which prevents the degradation of nearly 68% of the material in aqueous media over the course of ca. 1 month.

Thermolysis of molecular precursors followed by liquid phase exfoliation accesses 2-D IV–VI semiconductor nanomaterials.

Metal sulfide and metal oxide alloys of the form Mo 1– x W x S 2 and Mo 1– x W x O 3 (0 ≤ x ≤ 1) are synthesized with varying nominal stoichiometries ( x = 0, 0.25, 0.50, 0.75, and 1.0) by thermolysis of the molecular precursors MoL 4 and WS(S 2 )L 2 (where L = S 2 CNEt 2 ) in tandem and in various ratios. Either transition-metal dichalcogenides or transition-metal oxides can be produced from the same pair of precursors by the choice of reaction conditions; metal sulfide alloys of the form Mo 1– x W x S 2 are produced in an argon atmosphere, while the corresponding metal oxide alloys Mo 1– x W x O 3 are produced in air, both under atmospheric pressure at 450 °C and for only 1 h. Changes in Raman spectra and in powder X-ray diffraction patterns are observed across the series of alloys, which confirm that alloying is successful in the bulk materials. For the oxide materials, we show that the relatively complicated diffraction patterns are a result of differences in the tilt angle of MO 6 octahedra within three closely related unit cell types. Alloying of Mo and W in the products is characterized at the microscale and nanoscale by scanning electron microscopy–energy-dispersive X-ray spectroscopy (EDX) and scanning transmission electron microscopy–EDX spectroscopy, respectively.

In this work, we apply liquid cascade centrifugation to highly concentrated graphene dispersions produced by liquid-phase exfoliation in water with an insoluble bis-pyrene stabilizer to obtain fractions containing nanosheets with different lateral size distributions. The concentration, stability, size, thickness, and the cytotoxicity profile are studied as a function of the initial stabilizer concentration for each fraction. Our results show that there is a critical initial amount of stabilizer (0.4 mg/mL) above which the dispersions show reduced concentration, stability, and biocompatibility, no matter the lateral size of the flakes.