Herein, we are reporting a rapid one-pot synthesis of MoS2-decorated laser-induced graphene (MoS2-LIG) by direct writing of polyimide foils. By covering the polymer surface with a layer of MoS2 dispersion before processing, it is possible to obtain an in situ decoration of a porous graphene network during laser writing. The resulting material is a three-dimensional arrangement of agglomerated and wrinkled graphene flakes decorated by MoS2 nanosheets with good electrical properties and high surface area, suitable to be employed as electrodes for supercapacitors, enabling both electric double-layer and pseudo-capacitance behaviors. A deep investigation of the material properties has been performed to understand the chemical and physical characteristics of the hybrid MoS2-graphene-like material. Symmetric supercapacitors have been assembled in planar configuration exploiting the polymeric electrolyte; the resulting performances of the here-proposed material allow the prediction of the enormous potentialities of these flexible energy-storage devices for industrial-scale production.

In certain polymers the graphenization of carbon atoms can be obtained by laser writing owing to the easy absorption of long-wavelength radiation, which generates photo-thermal effects. On a polyimide surface this process allows the formation of a nanostructured and porous carbon network known as laser-induced graphene (LIG). Herein we report on the effect of the process parameters on the morphology and physical properties of LIG nanostructures. We show that the scan speed and the frequency of the incident radiation affect the gas evolution, inducing different structure rearrangements, an interesting nitrogen self-doping phenomenon and consequently different conduction properties. The materials were characterized by infrared and Raman spectroscopy, XPS elemental analysis, electron microscopy and electrical/electrochemical measurements. In particular the samples were tested as interdigitated electrodes into electrochemical supercapacitors and the optimized LIG arrangement was tested in parallel and series supercapacitor configurations to allow power exploitation.

The effects on 4H-silicon carbide epilayers of irradiation with protons and electrons having particle energies, respectively, of 6.5 and 8.2MeV were carefully studied and critically compared. In detail, the electronic levels associated with the irradiation-induced defects were analyzed by current-voltage characteristics and deep-level transient spectroscopy (DLTS) measurements up to 550K. In the same temperature range the apparent free-carrier concentration was measured by capacitance-voltage characteristics in order to monitor compensation effects due to the deep levels associated with the induced defects. Introduction rate, enthalpy, and capture cross section of such deep levels were compared. We found that a set of deep levels (at ET=0.39eV, ET=0.65eV, and ET=0.75eV) is the same in both cases of proton and electron irradiations, whereas two other pairs of levels (S1, ET=0.20eV and S1*, ET=0.23eV; S5, ET=1.09eV and S5*, ET=0.89eV) appearing in the same temperature range within the DLTS spectra should be associated with different defect complexes according to the irradiation type. Some conclusions regarding the microscopic nature of the defects related to the deep levels have been drawn.

Articles you may be interested inResonance-mode effect on microcantilever mass-sensing performance in air Rev. Sci. Instrum. 79, 074301 (2008);This work is focused on the developing of silicon resonant microcantilevers for the measurement of the absolute pressure. The microcantilevers have been fabricated with a two-mask bulk micromachining process. The variation in resonance response of microcantilevers was investigated as a function of pressure ͑10 −1 -10 5 Pa͒, both in terms of resonance frequency and quality factor. A theoretical description of the resonating microstructure is given according to different molecular and viscous regimes. Also a brief discussion on the different quality factors contributions is presented. Theoretical and experimental data show a very satisfying agreement. The microstructure behavior demonstrates a certain sensitivity over a six decade range and the potential evolution of an absolute pressure sensor working in the same range.

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