DC Conductivity Studies Research Articles

Characterization and Temperature dependent DC conductivity study of bio templated nickel oxide nanoparticles (NiO) and their composites using polyaniline (PANI)

Nickel oxide (NiO) nanoparticles with an average dimension of 28 nm were prepared via the Sol-Gel method using rice starch as bio template at 500 °C for 3h. The DC conductivity of pure NiO nanoparticles measured 1.015 х 10−4 S/cm−1 at room temperature, limiting its wider use in electrical applications. Hence the conductivity of pure NiO was modified by doping polyaniline (PANI). Polyvinyl pyrrolidone (PVP) stabilized polyaniline was synthesized by the oxidative polymerization of aniline using ammonium persulfate and hydrochloric acid as a dopant. The synthesized NiO-PANI composites were subjected to temperature dependent DC conductivity study in the range of 30–150 °C and maximum conductivity 2.1129 х 10−2 S/cm−1 was obtained at 90 °C.

Preparation and Characterization of Gel Polymer Electrolyte Based on PAN- NH4CF3SO4 and Nano ZrO2 Filler –Application as an Electrochemical cell

In the present investigation, the Nano Composite Gel Polymer Electrolyte (NCGPEs) based on nano fillers ZrO2, Polyacrylonitrile (PAN), and Ammonium Triflate (NH4CF3SO4) doped at various wt% ratios prepared with the help of solution cast technique. The better amorphous nature observed for the 70PAN:30NH4CF3SO4 composition with addition of 1-4 wt% of ZrO2 nano fillers and structural, complexation studies of NCGPEs were confirmed by XRD technique. The micro structural studies and particle size can be revealed by SEM technique. DC Conductivity studies reveal the ionic conductivity performance on effect of temperature and composition wt% of nano powder. The ionic conductivity studies observed for 70PAN:30NH4CF3SO4 with nano powder ZrO2 concentration ranging from 1-4 wt%. The sample containing 3wt% of ZrO2 exhibits the highest conductivity order of 4.20x10-4 S cm-1 at room temperature (303K) and 4.65x 10-3 S cm-1 at 373K. The cell parameters like Open Circuit Voltage, Short Circuit Current, energy density and power density were perfectly determined which were useful to explain electrochemical cell behaviour.

Observation of enhanced humidity sensing performance and structure, dielectric, optical and DC conductivity studies of scandium doped cobalt chromate

In the present investigation, we have examined the evolution and influence of Sc3+ content on the structural, microstructural, UV–Visible, Dielectric, DC conductivity and humidity sensing performance of Cobalt chromate viz., Co(1−x)ScxCr2O4 nanoparticle are synthesized by modified solution combustion method using mixture of carbamide and glucose as fuel. For sintered powder to study the Crystallinity, phase purity, Structure analysis are done by using X-ray diffractogram (XRD). The results of the XRD analysis give rise to all the samples are exhibit single phase with spinel cubic structure. Further the crystallite size was observed in nano region. The increase of the lattice parameter provides evidence for the effective substitution of Sc3+ at A site. The surface morphology, microstructure and elemental analysis are done by using SEM and EDS respectively. The SEM micrographs reveals that material are exhibits highly porous nature and producing agglomeration. The results of EDS confirms perfect elemental composition and there is no impurities in the samples. Particle size of both samples were estimated from particle size distribution diagram. The UV–Vis diffuse reflectance analysis were used to estimate the band gap of the samples. To understand the electrical behaviour of the samples we have done dielectric properties as a function of frequency. Dielectric measurements reveal that dielectric constant is loos tangent decreases with increasing frequency and it is constant for higher frequency side, this can be discussed using Koop’s theory. For estimate the activation energy DC conductivity measurements used. The specific surface range (SSA) are analyzed by using Brunauer–Emmett–Teller (BET) measurement and were found 165 Cm3/g STP and 40,790 Cm3/g STP. Further the average pore diameters were found 38 and 28 nm. To explore the response of the material at different humidity levels humidity sensing measurements carried out and humidity sensing response coefficient is estimated. From this study the fundamental behaviour of the synthesized materials at different standards were evaluated for various industrial applications.

Structural, Electrical, Thermal and Transport Properties of Poly Pyrrole/La0.7Ca0.3MnO3 Perovskite Manganite Nano Composite Studies Above Room Temperature

This paper presents the thermal studies of organic–inorganic [Poly Pyrrole (PPy)–Lanthanum calcium manganite (LCM)] nano composites synthesized via facile in situ chemical oxidation and sol gel methods respectively. The morphology and crystal structure were analysed through scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD) techniques respectively. The ac electrical conductivity, transport properties like dielectric constant, dielectric loss, real and imaginary part of electric modulus of pure PPy and PPy/LCM nano composites were analyzed in the temperature range 30 °C to 180 °C and in the frequency range from 100 Hz–5 MHz. Thermal stability of pure PPy and PPy/LCM nano composites were analyzed in the temperature range 30 °C to 800 °C by Thermogravimetric analysis (TGA) and Differential thermal analysis. The contributor for thermal degradation were analysed by fourier transmission infra red studies. DC conductivity study was carried out in the temperature range 30 °C to 180 °C. The activation energy was calculated using arrhenius plots. SEM and TEM images show spherical structure for pure PPy, agglomeration for pure LCM and PPy/LCM nano composites show spherical with LCM embedded in the PPy chain. The XRD analysis for pure PPy, LCM and PPy/LCM nano composites show amorphous, orthorhombic and semicrystalline structures respectively. AC electrical conductivity of the samples tend to merge at high frequency side. Dielectric constant show frequency dependence at all temperature. Real and complex electric modulus analysis show contribution of grain and grain boundary for the ac electrical conductivity. DC conductivity shows ionic conduction. The AC and DC conductivities were found to be high for PPy/LCM30 weight percent and PPy/LCM40 weight percent nano composites respectively. The activation energy of PPy/LCM40 was found to be high. TGA shows that the glass transition temperature of pure PPy is not much affected with the incorporation of LCM nano particle to the PPy chain.

Effect of nickel doping on the electrical conductance properties of La0.67Ba0.33Mn1-xNixO3 (x=0 and 0.075) manganite

The effect of nickel doping on the morphological and electrical properties of La0.67Ba0.33Mn1-xNixO3 (x = 0 and 0.075) manganite prepared by sol-gel process was undertaken. The morphology and grain size of these samples were carried out using scanning electron microscopy (SEM). Our samples have a homogeneous and porous morphology. The average grain size decreases from 130 nm (for x = 0) to 110 nm (for x = 0.075). Electrical measurements were investigated using conductance spectroscopy technique in 102–106 Hz and 80–320 K, frequency and temperature ranges, respectively. AC and DC conductance analysis indicate that both compounds exhibit a metal-semiconductor transition at TMS, which decreases from 240 to 220 K with Ni doping. From DC conductance study, conduction mechanism is found to be dominated by the small polaron hopping process at high temperature. Activation energy is deduced from the variation of conductance with temperature. This energy increases from 34 meV for x = 0–70 meV for x = 0.075. This behavior can be related to the reduction of the density of charge carriers with nickel concentration. The variation of the conductance with frequency follows Drude model.

Lithium ion conductivity in Li2O–P2O5–ZnO glass-ceramics

A series of new glass-ceramic samples containing Li2O has been prepared to explore their electrical transport properties. XRD patterns of them reveal the formation of different types of nanocrystallites, dispersed in amorphous glassy matrices. Study of dc conductivity (σdc) of them shows their thermally activated nature. Formation of more non-bridging oxygen in the compositions may enhance their ionic conductivity. Conductivity spectra at various temperatures have been studied and interpreted using Jonscher's universal power-law and Almond-West formalism to shed some light on transport mechanism. The frequency independent conductivity (plateau region) in low-frequency zone is caused by diffusion of Li+ ions. Moreover, in the high-frequency dispersive region, the conductivity is because of correlated and pseudo-three-dimensional motion of Li+ ions in percolating networks. In consequence, the power-law exponent values become greater than 1 and exhibit super-linear and/or NCL (nearly constant loss) nature. Correlated barrier hopping (CBH) model is modified to some extent, which yields a better fit to experimental results. Here, ion hopping and characteristic relaxation times have been correlated with electrical conductivity with good precision. The master curve in conductivity scaling analysis reveals that conductivity relaxation process in the present system are independent of temperature as well as composition.

Synthesis, DC conductivity and Dielectric studies on double doped Strontium Bismuth Niobate Ceramics

The Strontium Bismuth Niobate SrBi2Nb2O9 (SBN), K0.025Sr0.95Gd0.025Bi2Nb2O9 (KSGBN1) and K0.05Sr0.9Gd0.05Bi2Nb2O9 (KSGBN2) ceramics were prepared by two stage solid state reaction method. Crystal structure of sintered samples was studied by powder X - ray diffraction technique. XRD patterns well matched with reported data (ICSD #82280).The lattice parameters of the samples were calculated using POWD Software. Pellets of 10mm diameter and thickness about 1mm∼2mm were prepared and final sintered in the temperature range 900°C ∼950°C for four hours. The surface morphology of the samples was studied from Scanning electron Microscope pictures. The Temperature dependence of DC conductivity and dielectric properties were obtained and analyzed. Conclusions arrived at are presented.

Synthesis and DC conductivity studies of multivalent substituted ABO3 perovskite KNN multifunctional ferroelectric materials

Lead free piezoelectric samples of ABO3 perovskite structure were prepared, via double sintering method, having composition (K0.5Na0.5)(1-x)Li(x)(Zr0.025Nb0.98) (x =0.0,0.025). In these compounds Li partially replaced K and Na at A site whereas B site was doped with Zr = 0.025 in place of Niobium. Another sample with formula (K0.5(Na0.475Li0.025))(Zr0.025Nb0.98))O3 was also formed where only Na was replaced with Li (0.025), keeping K as (0.5) and Zr/Nb in the same ratio as in previous sample . All the three samples were prepared by using solid state reaction method. Hygroscopic K2CO3 and Na2CO3materials were preheated before using for grinding. All the raw materials were taken in stoichiometric ratio, then ground for eight hours and later calcined at different temperatures and times. Calcined powders were pelletized with dimensions of 10mm diameter and 1 to 1.5 mm thickness. Sintering temperature and duration of sintering were different for different samples. These pellets were used to studythe structure of the samples through XRD. SEM micrographs were taken to observe grain structure and DC conductivity properties of all the samples were studied. From DC conductivity plots, activation energies for conduction were obtained. Results obtained are discussed.

Impact of Ce content on cubic phase cerium–cadmium oxide (Ce–CdO) nanoparticles and its n-CeCdO/p-Si junction diodes

Microwave irradiation method was adopted to synthesize Ce doped CdO nanoparticles. The n-CeCdO/p-Si junction diode was fabricated and it’s parameters have been studied at different doping concentrations (0, 5, 10, and 15 wt%) of Ce. The Ce doping effect was analyzed by various characterization techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photo electron spectroscopy (XPS), ultra violet–visible spectroscopy (UV–Vis) and DC conductivity (I–V) studies. From XRD analysis, the Ce–CdO nanoparticles depicted a crystalline nature and showed the cubic phase. The crystallite size of the samples varied from 18.72 to 14.68 nm. TEM images reveal that the Ce–CdO nanoparticles have nail-like structure. The presence of the elements Ce, Cd and O were confirmed by EDX and XPS studies. The optical bandgap value decreases with the increasing doping concentration and the minimum band gap energy of 2.70 eV is obtained for 15 wt% Ce–CdO sample. I–V curve represents the semiconducting behavior of Ce–CdO nanoparticles. Variation of current in Ce doped CdO nanoparticles exhibits linear response to applied voltage. The diode behavior was studied under darkness and illumination environment. The major diode parameters, ideality factor and barrier height of n-CeCdO/p-Si junction diode were examined using J–V method.

Pure and copper doped cellulose microfibers-a case study

Our work demonstrates the improvement of intrinsic properties of cellulose microfibers upon copper doping. Cellulose microfibers were extracted from cotton by hydrolysis process. These were further doped with copper (Cu) to see the effect of dopant on optical, structural and conducting properties. We investigated the potential usage of these microfibers to solar cell applications. The evolution of cellulose microfibers has been comprehensively investigated with increasing dopant concentration of Cu (5 to 15%). Scanning electron microscopy gives clear images of cellulose microfibers of average diameter 5–10 μm. Absorption spectra of all samples showed an onset of absorption between 5.07 to 3.93 eV. A red shift was observed in band gap upon doping which is indicative that Cu has been incorporated into cellulose. DC conductivity studies reveal an improvement in conductivity values after Cu doping (303 to 363 K) from 8.89 × 10−5 to 5.04 × 10−4 S cm−1. These fibers were then coated over a Si solar cell and found an increase in short circuit current from 66 to 100 mA. The increase in short circuit current is attributed to charge transfer because of Cu metal and further reduces electron hole recombination which in turn improved the overall efficiency.

Structural, optical and electrical properties of Cu doped α-Fe2O3 nanoparticles

Undoped and Cu doped α-Fe2O3 (Hematite) nanoparticles (NPs) were synthesized through chemical precipitation technique. X-ray diffraction (XRD) analysis employing Rietveld refinement along with transmission electron microscopy was used for the structural characterization of the NPs. The progressive decrease in the intensity of the XRD peaks and the absence of any peak related to copper oxide phase was interpreted as an indication of the substitutional doping of the NPs. The decrease in the size of the doped NPs with increase in the dopant concentration was explained based on self purification mechanism by which the concentration of the dopant was more near the grain boundaries compared to that near the core. The decrease in the band gap of the NPs with increase in the dopant concentration was a result of substitutional doping. Also, the decrease in the intensity of the Raman peaks with increase in the atom % of Cu was explained as an effect of decreased scattering efficiency of the doped NPs due to an increased concentration of the dopant near the grain boundaries. The photoluminescence intensity of the samples was found to decrease with increase in Cu doping concentration and this was attributed to Cu-Cu luminescence quenching interactions. Analysis of EPR spectrum of undoped α-Fe2O3 NPs showed a weak ferromagnetic character of the sample while that of the Cu doped sample confirmed the incorporation of paramagnetic Cu2+ ions into α-Fe2O3 lattice. DC conductivity study of drop-cast films of undoped and Cu doped α-Fe2O3 NPs showed that the conductivity increased with increase in the doping concentration and that the conductivity approximately satisfied the reported models for its temperature dependence.

Preparation of new and novel wave like poly(2-anisidine) zirconium tungstate nanocomposite: Thermal, electrical and ion-selective studies

Abstract It is necessary to synthesize new material for the advancements of the technology. In this study, new and novel poly(2-anisidine)@zirconium tungstate (P2A/ZrW2O8) was synthesized by simple so-gel method. Physicochemical characterization of P2A/ZrW2O8 was done by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ion exchange and simultaneous four probe dc conductivity studies. The conductivity study revealed its highly semiconducting nature, in the range of 10− 1–10− 2 S·cm− 1. Ion-exchange capabilities of the composite make it applicable for cation-exchange studies. The result of distribution studies (Kd) revealed its selectivity towards Cd2 + compared to other metal ions. This property of the composite was utilized for designing Cd2 + selective membrane electrode. Several important physical parameters of the ion-selective electrode were determined, such as Nernstian slope (32.32 mV·decade− 1), working pH range was 2.0–4.0 and response time was found ~ 17 s. The analytical utility of this wave like composite membrane electrode was as, indicator electrode in various potentiometric titrations.

Influence of Neodymium and gamma rays irradiation on structural electrical and magnetic properties of Co-Zn nanoferrites

Nanostructured Co1-xZnxNdyFe2-yO4 (0 ≤ x ≤ 1.0; y = 0.0 and 0.1) ferrites were synthesized through combustion route. All the compositions were irradiated with 60Co gamma with total exposure dose 310 kGy at the dose rate 6.1kGy/h. The virgin and irradiated nanoparticles were characterized by the techniques; XRD, FTIR, SEM and EDAX. The DC electrical conductivity was measured in temperature range 300–800K. Magnetic parameters were measured with vibrating sample magnetometer (VSM) at 300K. Characterization studies reveal the structure, size, morphology and composition of the nanoferrites. The x-ray diffraction analysis revealed the cubic spinel ferrite structure. The characteristic feature of nanoferrites was confirmed by two prominent absorption bands ν1 and ν2 in the range 566–607 cm−1 and 401-498cm−1. The SEM micrographs evidenced almost spherical shaped agglomerated grainy structure of nanoferries. DC conductivity studies revealed that Curie temperature (TC) decreased with increasing Zn2+ ion and Nd3+ ion substitution due to the weakening of A–B interaction. The observed enhancement of DC conductivity and magnetic parameters on γ-irradiation attributed to the rearrangement of cations at A-site and B-site in the lattice.

Spectroscopic, dielectric dispersion and dc conductivity studies of Sb2O3doped lithium fluoro borophosphate glasses mixed with small concentrations of NiO

Glasses of the composition(20–x) LiF–10 Sb2O3–10 B2O3–60P2O5: x NiO(0 < x < 0.25) were synthesized by conventional rapid melt quenching method. The non–crystalline nature of the samples was confirmed by XRD analysis and the glass forming abilities were analyzed by DTA studies. The compositional dependence of structural aspects of the glasses was analyzed by FT–IR and Raman studies. The DTA, FT–IR and Raman studies suggested an increasing degree of disorder in the glass network with increasing concentration of NiO up to 0.20 mol %. The reversal trend observed beyond 0.20 mol% is attributed to an increasing polymerization of glass network. The optical absorption (OA) and photoluminescence (PL) studies were also carried on these glasses. The results of OA and PL spectral studies suggested that the gradual increase of octahedral Ni2+ ions with the increase in the concentration of NiO up to 0.20 mol%. Electrical properties viz., dielectric dispersion, DC and AC conductivity of the titled glass samples were also performed on titled glass samples. The observed increase in the values of dielectric constant, dielectric loss and AC conductivity (at any frequency and temperature) with the increase in the concentration of NiO up to 0.20 mol%is ascribed to the increasing space charge polarization in the glass network. The results of conductivity studies indicated that there is a mixed conduction (both ionic and polaronic) and the polaron hopping seems to prevail over ionic conduction in the glasses containing less than 0.20 mol% of NiO.

Structural, optical and electrical properties of pure and Fe doped V2O5 nanoparticles for junction diode fabrications

Structural, optical and electrical studies of V2O5 and FexV2O5 (x = 5%) nanostructures synthesized by a wet chemical method have been reported. The synthesized nanostructures were characterized by XRD, SEM–EDX, HRTEM, XPS, UV(DRS), FT-IR, PL, TG–DTA, AC and DC conductivity study’s. The anorthic phase was observed in the XRD patterns of undoped and Fe doped samples which are prepared at low temperature. This anorthic phase was reduced with the heat treatment and gradually transformed into orthorhombic phase in the samples annealed at 600 °C for 1 h. The change in the surface morphology in the present samples from micro-rod to nanorods network seems to be dependent on the substitution of Fe. As observed from the PL analysis that the ultraviolet (UV) emission intensity was found to be decreased and exhibited a blue shift with the increase of Fe concentration. The analysis of AC and DC conductivity measurements recorded at room temperature in the temperature range of 303–403 K, revealed that the activation energy is high for Fe doped V2O5 compared to undoped V2O5. The junction diodes of n-V2O5/p-Si and V2O5:Fe/p-Si was successfully prepared by the nebulizer spray pyrolysis method. The (I–V) characteristics of nonlinear and asymmetric nature revealed the Schottky diode based behavior for pure and doped samples.

DC and AC Conductivity Study of Basalt Glasses Containing High Concentrations of Na+ Ions

Different glass samples prepared from Egyptian basalt with different Na2O content according to the composition [(100-x) basalt + x Na2O], where x = 10, 15, up to 35 mol%. The samples mixtures were melted at 1300 °C for 2 h. Each sample will be recognized from its sodium to basalt (S/B) ratio. The sample of 0.54 ratio exhibits a slight crystalline phase. As S/B ratio was increased, the density decreased gradually while the molar volume increased, and the pure amorphous nature was confirmed by comparing the experimental and the empirical density and molar volume values. The electrical conductivities, DC and AC, were found to increase as the (S/B) ratio was gradually increase up to 0.33, then the samples showed approximate stable value up to the sample of 0.54 ratio. While the activation energy showed gradual decrease up to 0.33 ratio, then it exhibits nearly a stable value. The activation energy values indicated that all the studied samples behave like semiconductors. It appeared also from the AC conductivity results that the relation of the s-factor with the sample temperature showed that the conduction mechanism of these samples obeys the correlated barrier hopping (CBH) model. The structure of the same samples was studied in our previous work by XRD, FTIR and Mossbauer spectrometer.

Influence of cobalt ions on spectroscopic and dielectric properties of Sb2O3 doped lithium fluoroborophosphate glasses

Glasses with compositions (20–x) LiF–10 Sb2O3–10 B2O3–60 P2O5: x CoO (0 < x < 0.25) were synthesized by conventional rapid melt quenching method. The non–crystalline nature of the samples was confirmed by XRD analysis and the glass forming abilities were analyzed by DTA studies. The compositional dependence of various structural vibrational units was analyzed by FT–IR and Raman studies. The DTA, FT–IR and Raman studies suggested a higher degree of disorder in the glass network with increasing concentration of CoO up to 0.15 mol%. The reversal trend has been observed beyond 0.15 mol% suggesting an increasing polymerization of glass network. The optical properties of LiF–Sb2O3–B2O3–P2O5: CoO glasses were analyzed by optical absorption and photoluminescence studies. The observations from OA and PL spectral studies suggested that the gradual increase of octahedral Co2+ ions with the increase in the concentration of CoO up to 0.15 mol%. At higher concentration i.e. above 0.15 mol% of CoO, there was a reduction in the concentration of octahedral Co2+ ions. The electrical properties of the glass samples were studied by both DC and AC conductivity studies. The dielectric dispersion analysis was also performed on the prepared glass samples. The results of these studies indicated that there is a mixed conduction (both ionic and polaronic) and the polaron hoping seems to prevail over ionic conduction in the glasses containing CoO less than 0.15 mol%. The increasing space charge polarization is responsible for enhanced values of dielectric constant, dielectric loss and AC conductivity for all frequency and temperature ranges with the increase in concentration of CoO up to 0.15 mol%.

Influence of Mn2+ ions on optical and electrical properties of Sb2O3 mixed lithium fluoro borophosphate glasses

Glasses with composition of (20–x)LiF–10Sb2O3–10B2O3–60P2O5:x MnO (0< x <0.5 mol%) were synthesized. The non-crystalline nature of the samples was confirmed by XRD analysis and the glass forming abilities were analyzed by DTA studies. The compositional dependence of various structural vibrational units was analyzed by FT–IR and Raman studies. DTA, FT–IR and Raman studies suggested a higher degree of disorder in the glass network with increasing concentration of MnO up to 0.3 mol %. The reversal trend has been observed beyond 0.3 mol% suggesting an increasing polymerization causing lower degree of disorder in the glass network. The optical properties of LiF–Sb2O3–B2O3–P2O5: MnO glasses were analyzed by optical absorption, photoluminescence and ESR spectra. The observations of ESR, OA and PL spectral studies suggested that the gradual increase of octahedral Mn2+ ions with the increase in the concentration of MnO up to 0.3 mol%. At higher concentration i.e. above 0.3 mol% of MnO, there was a reduction in the concentration of octahedral Mn2+ ions. The electrical properties of the glass samples were studied by both DC and AC conductivity studies. The dielectric dispersion analysis was also performed on the prepared glass samples. The results of these studies indicated that there is a mixed conduction (both ionic and polaronic) and the polaron hoping seems to prevail over ionic conduction in the glasses containing MnO less than 0.3 mol%. The increase in space charge polarization is responsible for enhanced values of dielectric parameters and AC conductivity for all frequency and temperature ranges.

Effects of doping concentration on structural, morphological, optical and electrical properties of tungsten doped V2O5 nanorods

Pure and tungsten-doped V2O5 (WxV2O5; x = 5%, 10% and 15%) nanorods were produced by the wet chemical method followed by annealing at 60 °C for 12 h and 600 °C for 1 h. The influence of dopant concentration on the structural, morphological, optical and electrical properties of V2O5 nanorods were investigated through XRD, SEM-EDS, TEM, PL and DC conductivity studies. XRD pattern analysis reveals that the pure and tungsten doped samples are annealed at 60 °C exhibits anorthic phase and annealed at 600 °C, the anorthic is phase disappeared and emerged as an orthorhombic phase. Also, structural analysis shows that the WxV2O5 (x = 15%) lattice is found to be secondary phase. The gradual morphological transformation of nanostructures due to the incorporation of tungsten is depicted through SEM/TEM characterizations. The relative differential structure of tungsten-doped V2O5 nanorods is promptly registered by SEM analysis. EDS result confirms the presence of tungsten and also oxygen vacancies in doped V2O5. The PL quenching was observed with doping is due to the absorption of energy from the defect emission in the V5+ lattice by W6+ ions. DC conductivity of WxV2O5 with respect to different temperatures is explained by the presence of defects. Further, the colloidal form of pure and n-WxV2O5 is used to deposit on p-Si substrate for formation of p-n junction by the nebulizer spray technique and the properties of fabricated diodes are investigated under dark and illumination conditions. Also, the Norde's method is used to evaluate the series resistance and barrier height of the Schottky contact. Further, the transient photocurrent measurements were carried out to analyze the photoresponse of the developed diodes.

Structural and Conductivity Studies of LiCo1–xMnxO2 Cathode Materials

Present work aims at improving the characteristics of cathode material LiCo1–xMnxO2 for Li-battery by increasing the concentration of manganese. The titled compound LiCo1–xMnxO2 (x=0.0(LCO), 0.2(LCM2), 0.4(LCM4), 0.6(LCM6), 0.8(LCM8) and 1.0(LMO)) is prepared by solid state and sol-gel reaction methods. The structural studies of all the powders calcined at 850°C temperature for 20 h in the air are undertaken through powder X-ray diffraction. The diffraction patterns of these compounds are consistent with the reported patterns and exhibit predominant peak (0 0 3) orientation at 2θ = 19.08° and also other characteristic planes. The lattice parameters and the density are also reported. The surface morphological studies carried out using scanning electron microscope indicates average grain size of around 600 nm. FTIR studies show characteristic vibrations at 253, 304, 823, 1402 and 1619 cm–1 in the material. DC conductivity studies of the samples are measured from room temperature to 500°C and activation energies are calculated. These results are interpreted to understand the charge transport in the material.