Highly Porous and Ultra-Lightweight Aero-Ga2O3: Enhancement of Photocatalytic Activity by Noble Metals.

A new type of photocatalyst is proposed on the basis of aero-ß-Ga2O3, which is a material constructed from a network of interconnected tetrapods with arms in the form of microtubes with nanometric walls. The aero-Ga2O3 material is obtained by annealing of aero-GaN fabricated by epitaxial growth on ZnO microtetrapods. The hybrid structures composed of aero-Ga2O3 functionalized with Au or Pt nanodots were tested for the photocatalytic degradation of methylene blue dye under UV or visible light illumination. The functionalization of aero-Ga2O3 with noble metals results in the enhancement of the photocatalytic performances of bare material, reaching the performances inherent to ZnO while gaining the advantage of the increased chemical stability. The mechanisms of enhancement of the photocatalytic properties by activating aero-Ga2O3 with noble metals are discussed to elucidate their potential for environmental applications.

Mesenchymal stem cells proliferation and remote manipulation upon exposure to magnetic semiconductor nanoparticles.

In this paper, we report on spatial redistribution of bone marrow mesenchymal stem cells loaded with magnetic nanoparticles under the influence of continuously applied magnetic field. Semiconductor nanoparticles were synthesized by epitaxial growth of a GaN thin layer on magnetic sacrificial core consisting of ZnFe2O4 nanoparticles. Different quantities of nanoparticles were incubated in vitro with mesenchymal stem cells. High density of nanoparticles (50 µg/ml) leads to a decrease in the number of cells during incubation, while the density of nanoparticles as low as 10 µg/ml is enough to drag cells in culture and rearrange them according to the spatial distribution of the magnetic field intensity.

Hierarchical Aerographite 3D flexible networks hybridized by InP micro/nanostructures for strain sensor applications.

In the present work, we report on development of three-dimensional flexible architectures consisting of an extremely porous three-dimensional Aerographite (AG) backbone decorated by InP micro/nanocrystallites grown by a single step hydride vapor phase epitaxy process. The systematic investigation of the hybrid materials by scanning electron microscopy demonstrates a rather uniform spatial distribution of InP crystallites without agglomeration on the surface of Aerographite microtubular structures. X-ray diffraction, transmission electron microscopy and Raman scattering analysis demonstrate that InP crystallites grown on bare Aerographite are of zincblende structure, while a preliminary functionalization of the Aerographite backbone with Au nanodots promotes the formation of crystalline In2O3 nanowires as well as gold-indium oxide core-shell nanostructures. The electromechanical properties of the hybrid AG-InP composite material are shown to be better than those of previously reported bare AG and AG-GaN networks. Robustness, elastic behavior and excellent translation of the mechanical deformation to variations in electrical conductivity highlight the prospects of AG-InP applications in tactile/strain sensors and other device structures related to flexible electronics.

Ultra-lightweight pressure sensor based on graphene aerogel decorated with piezoelectric nanocrystalline films.

In this paper, we report on a pressure sensor based on graphene aerogel functionalized with SnO2 or GaN thin films deposited by magnetron sputtering. Decoration by nanocrystalline SnO2 or GaN was found to enhance the piezoresistive response of the bare aerogel. The responsivity and pressure sensing range (from 1-5 atm) of the sensor are shown to be higher than those inherent in pressure sensors based on graphene membranes.