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In this work, we investigated structural, electronic and optical properties of orthorhombic Mg2PN3 compound. The calculations were performed with full-potential linearized augmented plane-wave (FP-LAPW) method based on Density Functional Theory by using Wien2k packet. PBE-GGA (Perdew, Burke and Ernzerhof) were selected as exchangecorrelation functional. We calculated cell dimensions, bulk modulus and cohesive energy of this compound. The calculated structural parameters have good agreement with experimental works. We calculated DOS curve, electronic band structure, dielectric function, absorption coefficient and optical conductivity parameters. The DOS and electronic band calculations show that Mg2PN3 has indirect band gap with 5.2 eV value. [ABSTRACT FROM AUTHOR]

In this work, half-metallic (HM) properties of new Full-Heusler ferromagnetic compound Co2NiSi were studied by means of first principle band structure calculation within the framework of density functional theory (DFT). The structural calculations were performed with PBE-GGA (Perdew, Burke and Ernzerhof) potential. The magnetic and electronic properties were performed with Modified Becke-Johnson potential (mBJ). From the spin-polarized calculations using full-potential linearized augmented plane-wave (FP-LAPW) method, we have investigated structural, electronic and magnetic properties of Co2NiSi compound with both AlCu2Mn and CuHg2Ti structure type. Both compounds are metallic with spin up and have bandgap with spin down configuration. Total magnetic moment of Co2NiSi is calculated 3.07 μB and 3.28 μB for AlCu2Mn and CuHg2Ti structure type, respectively. The compounds has band gap below to Fermi level with 0.2 eV. So we found the Co2NiSi shows type III half metallic behavior. [ABSTRACT FROM AUTHOR]

In this study, conversion of kinetic energy from the decay of a radioactive isotope to electricity is investigated by using the direct and the indirect conversion methods. In this context, simple nuclear battery models are designed. Analysis for the effect of low-activity radiation from Pm147 and Sr90 beta sources on photovoltaic Si solar cell is presented. Beta radioluminescence nuclear battery models consist of a beta source, a phosphor layer and a solar cell. Phosphor layers with different mass thicknesses are prepared from ZnS:CuCl and SrAl2O4:Eu2+,Dy3+ phosphors. Both the influence of beta sources and the phosphor layers on battery performance is analyzed separately. Effect of beta sources, phosphors are observed on solar cell by measuring the short circuit current and open circuit voltage. The efficiency of the battery models is determined with the obtained results. Furthermore, short circuit current values are analyzed at various times during the irradiation. [ABSTRACT FROM AUTHOR]

Transport properties of electrons and holes were investigated not only in a anthracenecontaining poly(p-phenylene-ethynylene)- alt - poly(p-phenylene-vinylene) (PPE-PPV) polymer (AnE-PVstat) light emitting diodes (OLED) but also in an ITO/Ag/polymer/Ag electron and ITO/PEDOT:PSS/polymer/Au hole only devices. Mobility of injected carriers followed the Poole-Frenkel type conduction mechanism and distinguished in the frequency range due to the difference of transit times in admittance measurement. Beginning of light output took place at the turn-on voltage (or flat band voltage), 1.8 V, which was the difference of energy band gap of polymer and two barrier offsets between metals and polymer. [ABSTRACT FROM AUTHOR]

Because of the layered structure of vanadium pentoxide films (V2O5), approved by XRD measurement, sensitized from different hydrated V2O5.nH2O sols, demonstrated anisotropic conductivities in current voltage (I-V) measurement. Conductivity values, originated from electronic and ionic conductions, differed provided that measurements were performed in a direction parallel to the ribbons rather than perpendicular to them. The overall electrical conductivity of V2O5nH2O sols mainly depended on the hydration state n and the amount of reduced V4+ ions in which n was determined around 4-6 [1] from the basal distance (17.6 Å) through XRD measurement while V4+ ions were determined through FTIR analysis. Electronic conduction prevailed in dehydrated V2O50.5H2O sols whereas non-stoichiometric vanadium pentoxide was a mixed-valence compound and its electronic properties arised from electron hopping between V4+ and V5+ ions so-called 'small polaron model'. Indeed, reduction/oxidation peaks in lithium (Li+) intercalation by cyclic voltammograms (CV) indicated the V4+ and V5+ ions in V2O5 sols. Temperature dependent I-V analysis showed Arheniuss type activation energy, EA, and located in between 0.3-0.5 eV; proposing ionic conduction rather than electronic conduction, specifically proton diffusion in V2O5 film. Indeed, hydration state greater than 0.5 predicted ionic conduction [1]. [ABSTRACT FROM AUTHOR]

Vanadium pentoxide (V2O5) thin films were prepared by dip-coating sol-gel technique by dissolving V2O5 powder in hydrogen peroxide (H2O2), the solution, leading V2O5 sol-gel nanocrystalline films. The films under preparation were exposed different hydration states, n, varying from 6 to 2 determined via XRD measurements. Water molecules were adsorbed in layered structure of V2O5 oxide films and hence the adsorption could be described as an intercalation in which the molecules were trapped in some cavities and were not randomly oriented. (00l) pattern of X-ray diffraction analysis not only approved the one dimensional stacking of V2O5 ribbons but also served to determine basal distance from which hydration state was guessed. The basal distance were calculated from the position of 00l peak and varied from 17.2 Å to 10.6 Å that corresponded to n=6 to n=2 respectively. During the water departure upon heating, the basal distance reduced by steps of 2.8 Å (diameter of vander Walls water molecule) towards 8.8 Å value, attributed to n=0.5. Contrary to common belief of three-step mass loss (two of them were ascribed water expulsion), the process took place in two steps in thermo-gravimetric and differential thermal analysis (TG/DTA) measurements. During the first step, decrease in d exhibited huge endothermic negative thermal expansion of V2O5nH2O sol while crystallization into orthorhombic V2O5 occurred at 357°C (exhothermic peak) in TG as last step. [ABSTRACT FROM AUTHOR]

Vanadium pentoxide (V2O5) sols were formed through a reaction of V2O5 powder with hydrogen peroxide (H2O2); the solution evolves in time, beginning from diperoxo species, decavanadic acid spedies at intermediate step and finally polymerization of V2O5nH2O sols. From the sols, V2O5 thin films were succesfully fabricated on indium-tin-oxide (ITO) coated and corning glass substrates by sol-gel dip coating method. X-ray diffraction pattern of the films at hand exhibited a series of (00l) peaks that confirmed both some preferred orientation of a layered structure in one dimension stacking of ribbons perpendicular to the substrate and ability of employed method to produce nano crystal of V2O5nH2O sol-gel films. The basal distance, d, (increased with an amount of water in the sols in steps of 2.8 Å, attributed van der Walls water molucule diameter), was determined as 10.6-17.2 Å that corresponded n in between 2-6. On the other hand, the average particle sized, D, of the precipitated nanocrystals were calculated through Sherrer's formula and determined around 15-28 nm that consisted with AFM and SEM analysis. The electrochemical studies by cyclic voltametry showed the Li+ intercalation capacity, reversibility and stability. Finally, the simultaneous TG and DTA on the as prepared films indicated two stage mass loss. [ABSTRACT FROM AUTHOR]