Hydrogen sensors based on electrophoretically deposited Pd nanoparticles onto InP

Electrophoretic deposition of palladium nanoparticles prepared by the reverse micelle technique onto InP substrates is addressed. We demonstrate that the substrate pre-deposition treatment and the deposition conditions can extensively influence the morphology of the deposited palladium nanoparticle films. Schottky diodes based on these films show notably high values of the barrier height and of the rectification ratio giving evidence of a small degree of the Fermi level pinning. Moreover, electrical characteristics of these diodes are exceptionally sensitive to the exposure to gas mixtures with small hydrogen content

Dendrimer facilitated synthesis of multifunctional lanthanide based hybrid nanomaterials for biological applications

A poly(amido amine) (PAMAM) dendrimer has been successfully used for the first time as a linking agent for the synthesis of a luminescent lanthanide based multifunctional nanohybrid (YPO4:Tb3+@Fe3O4). Characterization of the materials was done by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). The HRTEM images showed spindle shaped YPO4:Tb3+@Fe3O4 in the presence of a PAMAM dendrimer which is due to the incorporation of the Fe3O4 nanoparticles in the branches of the PAMAM dendrimer when they are attached on the surfaces of the YPO4:Tb3+ nanorods. Photoluminescence studies showed the Tb-O charge transfer transition which is produced by electron delocalization from the filled 2p shell of the O2- to the partially filled 4f shell of Tb3+. The nanohybrid materials yielded a specific absorption rate (SAR) value of 39.22 W g(-1) of magnetite under the influence of an AC magnetic field of 110 Oe and 425 kHz frequency. Biocompatibility of the developed hybrid nanomaterials was evaluated in vitro by assessing their cytotoxicity on human cervical cancer cells (HeLa cells) using a sulforhodamine B (SRB) assay. These YPO4:Tb3+@Fe3O4 nanohybrids have potential biomedical applications in the area of imaging and magnetic hyperthermia

One-step synthesis of ZnO nanosheets: a blue-white fluorophore

Zinc oxide is synthesised at low temperature (80°C) in nanosheet geometry using a substrate-free, single-step, wet-chemical method and is found to act as a blue-white fluorophore. Investigation by atomic force microscopy, electron microscopy, and X-ray diffraction confirms zinc oxide material of nanosheet morphology where the individual nanosheets are polycrystalline in nature with the crystalline structure being of wurtzite character. Raman spectroscopy indicates the presence of various defects, while photoluminescence measurements show intense green (centre wavelength approximately 515 nm) blue (approximately 450 nm), and less dominant red (approximately 640 nm) emissions due to a variety of vacancy and interstitial defects, mostly associated with surfaces or grain boundaries. The resulting colour coordinate on the CIE-1931 standard is (0.23, 0.33), demonstrating potential for use as a blue-white fluorescent coating in conjunction with ultraviolet emitting LEDs. Although the defects are often treated as draw-backs of ZnO, here we demonstrate useful broadband visible fluorescence properties in as-prepared ZnO