TiO 2 nanotube arrays formed by electrochemical anodization of Ti metal foil are crystallized through a solvothermal technique at 200°C (as compared to conventional annealing at 550°C), which results in anatase phase with granular morphology. The photo-current measurements reveal a higher current-density under the visible light for solvothermally crystallized samples. The photocurrent behavior has been analysed and correlated with defect state characterization using X-ray photo-electron spectroscopy, Photo-luminescence, Electron paramagnetic resonance and Mott-Schottky measurements. These studies indicate an oxygen vacancy related defect state at 1.14 eV below the conduction band. Also, the density of defect states in solvothermally crystallised samples is an order of magnitude higher than that in conventionally annealed samples. Furthermore, the photo-voltaic properties are studied through dye-sensitised solar cells. I-V characteristics of DSSC fabricated with solvothermally crystallised samples show comparable efficiency but higher dye-adsorption with respect to the conventionally annealed samples. Such a comparable efficiency at a lower thermal budget leads to reduced 'energy pay-back time' in solar cells fabricated with solvothermally crystallised TiO 2 nanotube arrays. Finally, we demonstrate a proof-of-concept design of flexible solar cell based on TiO 2 nanotubes grown on Kapton substrate and crystallised through the solvothermal technique.

Ab-initio band structure calculation using the state-of-the-art density functional theory was carried out for the sample Pd2ZrGa. The equilibrium lattice parameter was found by fitting the energy vs volume data to Murnaghan equation of state and the value was observed to be 6.467 Å. Non analytical behavior of the energy functional was observed in band structure as well as in density of states diagram near the Fermi level. Polycrystalline sample synthesized using arc-furnace showed compositional variation in X-ray diffraction and energy dispersive analysis of X-ray spectrum studies. Magnetic measurements showed Meissner diamagnetic shielding in the as-cast sample below 2 K. From the Zero Field Cooled (ZFC) and Field Cooled (FC) measurements, we observed that the system is a type II BCS superconductor. The volume susceptibility at 2 K was observed to be 3.1 emu/Oe cm3.

Ribbons of Fe73.5Si13.5B8CuV3−xAlNbx (x = 0, 1.0, 1.5) alloys were prepared by melt-spun technique at the speed of 37 m/s. Crystalline phase derived from Fe3Si, in an amorphous matrix was observed in all the ribbons. As cast nanocrystalline ribbons were obtained by controlling cooling rates while quenching. The average crystallite sizes was calculated using the Scherrer's equation to be 44 nm, 39 nm, and 35 nm in x = 0, x = 1.0, and x = 1.5 ribbons, respectively. Magnetoimpedance measurements were carried out using an LCR meter. Among the investigated samples (x = 0, 1.0, 1.5), the largest magnetoimpedance of 61% was obtained for x = 1 ribbon annealed at 100 °C for 15 min, at 4 MHz.

No abstract