25 research outputs found
Enhanced electrical properties of vertically aligned carbon nanotube-epoxy nanocomposites with high packing density
Influence of the Alloying Elements on Pitting Corrosion of Stainless Steels: A Modeling ApproachÂ
International audienc
Effect of the final annealing of cold rolled stainless steels sheets on the electronic properties and pit nucleation resistance of passive films
International audienc
Effect of the passive film on the crevice corrosion of stainless steels : experimental and modeling approaches.
International audienc
Synthesis, characterization and photocatalytic behavior of Ag doped TiO2 thin film
Superlattices and Microstructures 85 (2015) 255–265In this study, structure, microstructure, optical properties and photocatalytic degradation
of Rhodamine B (RhB) have been investigated in an aqueous heterogeneous media containing
pure and Ag doped TiO2 nanostructures thin films which were prepared by a simple
sol–gel route. Thermal analysis demonstrated that Ag content decreased the temperature
of anatase-to-rutile phase transformation. X-ray diffraction analysis confirmed that the
prepared nanostructures crystallize within anatase-type structure and that the dopant
Ag ions were not fully incorporated within TiO2 host lattice, meanwhile both the refractive
index and optical band gap were affected by Ag concentration. The photodegradation of
Rhodamine B under UV-C radiation by using pure and Ag-doped TiO2 nanostructures
showed that Ag played an important role in a significant improvement of the photodegradation
efficiency and that the optimum content of Ag ions was found to be 0.5% molar rati
Probing anodic oxidation kinetics and nanoscale heterogeneity within TiO2 films by Conductive Atomic Force Microscopy and combined techniques
Structure, microstructure and determination of optical constants from transmittance data of co-doped Zn0.90Co0.05M0.05O (M@Al, Cu, Cd, Na) films
ZnO, Zn0.95Co0.05O and Zn0.90Co0.05M0.05O (M@Al, Cd, Na, Cu) single phase films have been successfully synthesized by ultrasonic spray pyrolysis technique. Structural analysis by X-ray diffraction show that all the films have hexagonal wurtzite structure with an average crystallite size in the range of 19–25 nm. SEM analysis revealed that Cd and Na preserve the shape of nanopetals observed with ZnO or CoAZnO films, while the doping with Al or Cu promote the formation of dense films constituted of nanorods. By the application of Levenberg–Marquardt least square method, the experimental transmittance data were fitted perfectly with the transmittance data calculated via a combination of Wemple– DiDomenico model, absorption coefficient of an electronic transition and Tauc–Urbach model. The concentration of absorbing centres NCo and oscillator strength f of d–d transition of Co2+ ions are calculated from Smakula’s formula
pH Controlled Nanostructure and Optical Properties of ZnO and Al-Doped ZnO Nanorod Arrays Grown by Microwave-Assisted Hydrothermal Method
The low-temperature microwave-assisted hydrothermal method was used to successfully grow pure and Al-doped ZnO (AZO) nanorod (NR) arrays on glass substrates. The combined effects of doping and pH on the structural properties, surface chemistry, and optical properties of all samples were investigated. Thermodynamic-based simulations of the growth solution were performed and a growth mechanism, that considers the effects of both the pH and Al-doping, is proposed, and discussed. Tuning the solution pH is key parameter to grow well-aligned, single crystal, highly packed, and high aspect ratio nanorod arrays. Moreover, the optical absorption in the visible range is enhanced by controlling the pH value. The PL spectra reveal a shift of the main radiative emission from the band-to-band into a transition involving deep defect levels of Zinc interstitial Zni. This shift is caused by an enhancement of the non-radiative components (phonon relaxation) at high pH values. The production of well-ordered ZnO and AZO nanorod arrays with visible-active absorption/emission centers would increase their potential use in various applications