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An ionic liquid (IL) 1-ethyl, 2-methyl imidazolium thiocyanate incorporated biopolymer system is reported in this communication for applications in dual energy devices, i.e., electric double-layer capacitors (EDLCs) and dye-sensitized solar cells (DSSCs). The solution caste method has been used to synthesize ionic-liquid-incorporated biopolymer electrolyte films. The IL mixed biopolymer electrolytes achieve high ionic conductivity up to the order of 10−3 S/cm with good thermal stability above 250 °C. Electrical, structural, and optical studies of these IL-doped biopolymer electrolyte films are presented in detail. The performance of EDLCs was evaluated using low-frequency electrochemical impedance spectroscopy, cyclic voltammetry, and constant current charge–discharge, while that of DSSCs was assessed using J–V characteristics. The EDLC cells exhibited a high specific capacitance of 200 F/gram, while DSSCs delivered 1.53% efficiency under sun conditions.

In this study, mild steel was treated with SDBS:ZnSO4 compound by immersing the mild steel substrates in a SDBS:ZnSO4 bath of varying pH. The effect of bath solution pH and immersion time on the corrosion protection properties of SDBS:ZnSO4 pre-treated mild steel in sodium chloride solution was investigated using electrochemical impedance spectroscopy (EIS) and polarization measurements. From the EIS results, it was found that the inhibition efficiency provided by the pre-treatment was significantly affected by the pH of the bath solution, where inhibition was highest at pH 6. This is due to the formation of a good protective layer on mild steel substrate caused by the deposition of zinc hydroxide/oxide and SDBS compound. Increasing the immersion time from 1 h to 24 h increased the inhibition efficiency. From the polarization measurements, the current density was significantly reduced, and the shift to a more positive corrosion potential value indicated a higher protection layer was formed on the metal surface during more prolonged immersion. It has been found that longer pre-treatment immersion time allows a denser protective layer formed, which prevented the diffusion of water towards the mild steel substrate that can lead to corrosion.

Lattice strain effects drive a variety of novel functional responses in epitaxial BiFeO3 thin films and have attracted significant interest and attention from researchers in experimental and theoretical studies. However, the difficulty in designing experimental techniques in addition to facing problems in the first principles approach, such as output accuracy and high computational costs, constitute the discovery of new functional responses in epitaxial BiFeO3 thin films not entirely understood. Therefore, in this study, we perform a first principles calculation based on the less expensive LDA+U method to investigate the structural phase instability and electronic properties change in BiFeO3 under the lattice strain effect. The structural phase transformation of BiFeO3 under volumetric and compressive/tensile lattice strain was examined established on the calculated lower energy phases. Importantly, we demonstrated that the change of crystal structure phases of BiFeO3 was extremely sensitive to the volumetric and compressive/tensile lattice strain, comparable with various experiment data, as reported in the literature. Moreover, we revealed for the first time from the first principles prediction the coexistence of mixed R-T phases in the region of moderate compressive ζin-plane of −2.9% (e.g. LaAlO3 substrates with ɑ = 3.79 A). From the prediction of electronic properties obtained by the LDA+U and PBE0 methods, we found that the energy band gap increased when the compressive in-plane lattice strain is increased while, in contrast, the energy band gap decreased when BiFeO3 was under the tensile in-plane lattice strain effect. We also demonstrate that our computational technique based on the first principles study was sufficiently accurate enough, helping to speed up the process of designing new materials having an excellent multifunctional response (piezoelectric, magnetic, photovoltaic, spintronic).

In this work, the film contained a mixture of PMMA, salt, and plasticizers are studied. PMMA as a host polymer, ammonium trifluoromethane sulphonate or ammonium triflate (NH4CF3SO3) as a doping salt and ethylene carbonate (EC) as a plasticizer is used in this present study. PMMA salt complexes system and plasticized PMMA salt complexes system are prepared by solution cast technique at room temperature. FTIR is used to study the interaction between polymer and salt, and between polymer–salt and plasticizer. The carbonyl group C=O asymmetric stretching mode observed at 1721 cm-1 is broadened and shifted to lower wavenumber when ammonium triflate was added into PMMA. The broadening, shifting and reduction in wavenumbers of FTIR spectra show that the complexation has occurred between the polymer and salt. EIS is performed to measure the electrical conductivity of the polymer–salt system prepared at ambient temperature. The electrical conductivity of film containing 1.0 g of PMMA–35 wt% NH4CF3SO3–16 wt% EC exhibit the highest electrical conductivity with the value of 2.461 x 10-4 S/cm2. XRD is carried out to study the pattern of pure PMMA, PMMA–NH4CF3SO3 and PMMA–NH4CF3SO3–EC. The XRD analysis shows the addition of plasticizer to the polymer–salt system increase the amorphousness of the polymer electrolytes hence increases in conductivity.

This study focuses on preparation and characterization of polymer gel electrolytes (PGEs) based on agarose–LiBOB–DMSO and poly(1-vinylpyrrolidone-co-vinyl acetate)–LiBOB–DMSO. Two systems of PGEs were prepared by dissolving a different amount (1-8 wt.%) of agarose and (1-8 wt.%) P(VP-co-VAc) as host polymer in 0.8 M of LiBOB–DMSO solution. The addition of host polymer into 0.8 M of LiBOB–DMSO solution will result an optimum conductivity which is 6.91 x 10-3 S.cm-1 for agarose–LiBOB–DMSO system and 7.83 x 10-3 S.cm-1 for P(VP-co-VAc)–LiBOB–DMSO system. In the temperature range of conductivity studies discovered that the agarose–LiBOB–DMSO and P(VP-co-VAc)–LiBOB–DMSO polymer gel electrolytes abide by Arrhenius rule indicating that this PGEs could run at elevated temperature conditions. Furthermore, lithium transference number confirms that both electrolyte systems have 0.03 and 0.12 respectively at room temperature (298 K). Linear sweep voltammetry (LSV) measurements demonstrate the agarose–LiBOB–DMSO system has a potential of 4.26 V and P(VP-co-VAc)–LiBOB–DMSO system has a potential of 4.50 V which is good in electrochemical stability.

In this work, single phase Bismuth Ferrite, BiFeO3 was successfully synthesized by using hydrothermal method assisted with different weight (0.24 g, 0.36 g and 0.48 g) of Chitosan. Potassium hydroxide (KOH) were used as a mineralizer during the synthesis process for the precipitation. The samples were characterized for different properties such as structural and optical properties, and were then compared with previous works. The X-ray diffraction data for all the samples showed that the samples had a single phase belonging to R3c space group with perovskite rhombohedral structure at diffraction angle 32.0° to 32.5° even though the slight presence of secondary phase at diffraction angle 28° was detected. Scanning electron microscope revealed a decrement in particle size as the weight of Chitosan increased indicating effective used of Chitosan in controlling the agglomeration of the particles. All samples BiFeO3 assisted with and without Chitosan showed significant enhancement in energy gap where the obtained results showed a small energy gap values ranging from ~1.22 eV to ~1.88 eV determined from UV-vis absorbance characterization. Therefore, by the addition of Chitosan, the properties of BiFeO3 such as structural and optical have changed as well as preventing from the particle to agglomerate.

Layered lithium iron hydroxysulfate, LiFeSO4OH was recently proposed as a cathode material for lithium ion batteries (LIBs) made up of low cost and sustainable components. Here, we report ab-initio investigation into the structural properties of its sodium analogue, NaFeSO4OH obtained from in-situ substitution of lithium (Li) with sodium (Na). A robust host structure for NaFeSO4OH was discovered owing to strong Fe-O and S-O bonds, a good indicator for thermal stability and long cycle life. The Na ions are strongly held by the oxygen atoms, but the charge density map proves that the bond between the two is still ionic.

Graphene-Zinc Oxide (Gr-ZnO) nanocomposites films were successfully synthesized via facile electrodeposition method in an aqueous solution under Gr concentration conditions. Gr, as a highly conductive carbon, acts as an anchor for ZnO nanosheets and plays a substantial role in controlling the degree of dispersion of ZnO nanosheets onto indium-doped tin oxide (ITO) substrate to form Gr-ZnO nanocomposite. Atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM) analysis of Gr-ZnO nanocomposite samples confirmed that the presence of ZnO nanosheets with a high degree of dispersity and crystallinity which is well linked to the thin layer of Gr nanoparticle on ITO substrate. The surface roughness of the films found increased to ~270 nm on Gr-ZnO as compared to Gr ~44 nm and ZnO ~3 nm. Further, the x-ray diffraction spectroscopy (XRD) analysis showed the result is in good agreement with Raman spectroscopy study. The cyclic voltammetry (CV) of Gr-ZnO nanocomposite revealed that the effect of electron-hole recombination process was increased and the presence of Gr in ZnO photoanode provides the fastest redox reaction and hence offers the fastest electron transfer in photoanode.

The morphology and electrochemical properties of electrodes made from graphene (Gr)-activated carbon (AC) composite (GrAC) doped with iron(III) tetramethoxyphenylporphyrin chloride (FeTMPP-Cl), hereafter referred to as GrAC-FeTMPP-Cl, are investigated in this study. The properties of the modified electrodes are considerably improved by modifying carbon through the introduction of transition metal catalysts into the hybrid carbon matrix. The hybrid GrAC exhibits superior electrochemical properties than those of materials with single components. Incorporating AC into Gr nanosheets prevents the aggregation of the nanosheets because the AC particles distributed between the Gr layers provide numerous pathways for electron transfer. The addition of FeTMPP-Cl to the electrode material, followed by pyrolysis, enhances the material’s electrochemical properties, including fast electron transfer, low charge transfer resistance and high redox current peaks, due to numerous accessible effective surface areas of the electrode. The pyrolysed GrAC-FeTMPP-Cl-modified electrode achieves the highest oxidation current peak of 0.088 mA, with an increment of 10.3% compared with GrAC (0.080 mA) at a scan rate of 20 mVs−1 in 5 mM K3 [Fe(CN)6]/0.1 M KCl electrolyte solution. Results demonstrate the high potential for applications of the pyrolysed GrAC-FeTMPP-Cl/indium tin oxide modified electrode in flexible energy storage devices.

Structural, electronic, and optical properties of ternary vanadium sulfides, XV2S4 (X = Ni, Cr, and Mo), are investigated using first-principles calculations based on density functional theory (DFT) method. The structural parameters, band structures, density of states (DOS), absorption coefficient, and conductivity are reported to discuss the properties of XV2S4 (X = Ni, Cr, and Mo) as potential Pt-free counter electrode for dye-sensitized solar cell (DSSC). Generally, nickel vanadium sulfide (NiV2S4) is predicted to be a good candidate as a counter electrode compares with chromium vanadium sulfide (CrV2S4) and molybdenum vanadium sulfide (MoV2S4) due to its ability to provide high electron density around Fermi level and high conductivity.

The effect of CO and NO adsorption on graphene (pristine, vacancy and doped) were investigated for structural and electronic properties. The sensitivity of palladium (Pd) doped graphene toward small gas molecules CO and NO have been investigated by using DFT calculation within Generalized Gradient Approximation (GGA) as implemented in DMol3 and CASTEP. The density of states, the most stable adsorption site and adsorption energy of these small gas molecules on vacancy graphene and Pd-doped vacancy graphene are thoroughly discussed. It is found that Pd doping significantly enhances the strength of interaction between adsorbed molecules and the modified substrates. The most stable adsorption site for CO and NO on all graphene sheets are identified and reported. The results present the potential of vacancy graphene and Pd-doped vacancy graphene for molecules sensor application. Novelty • The novelty of this paper is the doping of Pd on vacancy graphene surface could enhance the adsorption energy of CO and NO gas molecules. • Besides, most of the studies not using Pd on vacancy graphene to study its effect on small molecules.

A comparative study of structural, electronic and magnetic Ca2+, Sr2+ and Ba2+ A-site ion substitution of BiFeO3 with different Fe oxidation states was carried out. Calculation shows doped compounds favours energy stability in Fe oxidation states of 2+ and 4+ compared to 3+ charge. Electronic band gap makes significant changes with value of 1.32 eV, 1.36 eV and 1.31 eV for Ca, Sr and Ba doped respectively, compared to pure BiFeO3 of 1.41 eV. The net magnetization shows improvement with use of the dopant elements compared to pure BiFeO3. These changes indicate the role of the heterovalent dopant in BiFeO3.

First-principles calculations using density functional theory (DFT) have been performed to investigate the structural and electronic properties of TiO2 polymorphs in rutile, anatase and brookite phases. The calculations based on local density approximation (LDA) and generalized gradient approximation (GGA) for Perdew-Burke-Ernzerhof (PBE) and Perdew-Burke-Ernzerhof for solids (PBEsol) were performed by considering the effect of Hubbard U correction in Ti 3d electrons of the TiO2. The DFT+U calculation improved the underestimated band gap which could solve the standard DFT problems. The best agreement of U values is found at U = 8.5 eV for rutile using LDA, U = 8.5 eV for anatase using GGA-PBEsol and U = 7.5 eV for brookite using GGA-PBEsol to improve the electronic band gap of TiO2 as a match with the experimental band gap

This study explored the electronic and optical properties of nano-thin film orthorhombic bismuth selenide (Bi2Se3) using first-principles approach. The thin films were modelled in the [001] direction using slab geometry supercell with vacuum along z-direction so that periodic images and slab can be managed independently. We obtained band gap of 0.730 eV, 0.566 eV and 0.690 eV for 1, 2 and 3 slabs respectively. It shows dependence of band structure to the thickness of the films. The reduced band gap in Bi2Se3 films is due to the effect of quantum confinement. The electron contributions were increased as the thickness of the thin film increased. We also found that the thickness of Bi2Se3 thin film influences its optical properties. Higher thickness provides higher static dielectric function, refractive index, extinction coefficient, absorption coefficient and loss function. This study demonstrates Bi2Se3 thin film has good optical properties that are useful for optoelectronic applications.

Good thermoelectric performance is being sought to face major problems related to energy, especially in the concern of the usage of energy on environmental impact. In this work, we investigate the underlying mechanism to enhance the thermoelectric performance of bismuth selenide (Bi2Se3) by employing density functional theory (DFT) followed by the Boltzmann transport equation under relaxation time approximation. The structural, electronic, and thermoelectric properties were calculated and analyzed. From the analysis of combined results of thermoelectric properties and electronic properties as the function of the Fermi level, we found that the power factor of Bi2Se3 is improved by increasing electrical conductivity that contributed by the large density of states and light effective mass of charge carriers. The figure of merit, on the other hand, is enhanced by increasing Seebeck coefficient that contributed by heavy effective mass and decreasing thermal conductivity that contributed by low density of states. We also found that both power factor and figure of merit can be improved through n-type doping at 300 K and p-type doping at higher temperature (400 K and 500 K).

The increasing energy demand on available global lithium resources has created concerns on development of new and advanced sustainable energy sources. Sodium-based batteries have emerged as promising substitutions to Li-based batteries. We describe here sodium trifluoromethanesulfonate (NaCF3SO3) electrolyte system based on tetraethylene glycol dimethyl ether (tetraglyme). The ionic conductivity of the electrolytes showed a maximum value of 1.6 mS cm−1 for 40 mol% of NaCF3SO3 at room temperature and increased up to of 9.5 mS cm−1 at 373 K. The system showed the anodic stability of the electrolytes up to ca. 5.2 V (Na+/Na) and facile deposition of sodium began at relatively low overpotential, around − 0.01 V vs. Na+/Na, which showed a good reversibility of the electrolytes. Preliminary tests of the electrolyte in half sodium-ion cells employing Na3V2(PO4)3 as cathode electrodes were performed and the cells delivered capacity of 74 mAh g−1 at C/10.

Gun powder is predicted to be more expensive in relation to the world oil shortage crisis in the future. However, cellulose (generic chemical formula (C6H10O5) is the carbohydrate that makes up the main structure of plants. It is more economical especially for countries with a lot of natural resources and rain forests like Malaysia. The finding of the study reveals the capability of nitrocellulose as gunpowder. In this research, a comparison of the same mass of nitrocellulose and gunpowder is made to find out which propellant produce longer distance and greater impact. The main objectives of this study are to find out the performance and capability of nitrocellulose extracted from Rhizophora apiculata compared to gunpowder in terms of velocity, calorific value of bullets and kinetic energy produced. The result shows that the nitrocellulose has better performance than gun powder. The new application of smokeless gun powder ensures troops especially snipers hardly being detected by enemy and at the same time improves safety and security level.

Electrical dielectric spectra and alternating current (ac) conductivity of blended poly (N-vinlycarbazole) (PVK) with polyvinylpyrrolidone (PVP) at different temperature are investigated. The polymer blends were prepared by dissolving in dimethylformamide (DMF) using drop casting method and further dried in vacuum oven. The dielectric and ac conductivity of each sample was investigated using electrochemical impedance spectroscopy (EIS) method. Dielectric permittivity studies revealed that there are significant changes in the spectra at different temperature. The ac conductivity was further analyzed by using universal power law. The hopping parameter was calculated by using correlated barrier hopping model.

PbTiO3 has emerged as a promising material for the thermoelectric application. In this study, we proposed to use density functional theory to investigate the underlying mechanism for improving the thermoelectric efficiency of ATiO3. The thermoelectric parameters of the designed surface structures have been obtained by using the Boltzmann transport equation approximation. The properties of the structure, electronic, and thermoelectricity were measured and analyzed. The surface (001) modification through the AO termination layer has increased the electrical conductivity, thus increasing the power factor. On the other hand, increasing the Seebeck coefficient, which is aided by declining thermal conductivity, which is aided by low thermopower, improves the figure of merit. It is shown that the thermoelectric performance of surface (001) SnTiO3 is higher as compared to PbTiO3 making it interesting towards lead-free materials in thin-film application.

Sodium-based batteries have emerged as promising alternatives to Li-based batteries for future safe, high energy-density energy storage. They are expected to be cheaper, due to the greater abundance of Na and likely reduction in raw material costs. In this study, we investigate the properties of superconcentrated sodium bis(fluorosulfonyl)amide (NaFSI) mixtures with the ionic liquid (IL) methylpropylpyrrolinium (C 3 mpyr) FSI in the presence of ethylene carbonate (EC) in the liquid and gel states. Ionic conductivity and thermal stability are evaluated through electrochemical impedance spectroscopy (EIS) and differential scanning calorimetry (DSC), respectively. NaFSI is soluble in the IL up to 55 mol% Na; adding EC (30 wt.%) to the IL almost doubles the ionic conductivity at ambient temperature. The temperature dependence of conductivity is well described by the Vogel-Tamman-Fulcher equation. NMR spectroscopy and Pulse Field Gradient NMR diffusion were employed to investigate transport in these electrolyte systems, while the chemical interactions were also studied using ATR-FTIR. Stable plasticized gel electrolytes were observed, even at 30 wt. % EC; the formation of the gel does not significantly affect the liquid-like ion dynamics in these materials, as shown by DSC and FTIR analysis. The Na + transference number of Na 0 . 55 [C 3 mpyr] 0.45 [FSI] + 30 wt.% EC was up to 0.32, and deposition and dissolution of sodium metal were observed in cyclic voltammetry around 0 V vs. Na/Na + . Moreover, the suitability of the prepared electrolyte is preliminarily verified in half-cells at room temperature using Na 3 V 2 (PO 4 ) 3 as a cathode. The cells delivered capacity of 52.4 mAhg −1 at C/20.

First-principles calculations are performed to study the electronic properties of zinc oxide (ZnO) formed on an anode after discharging a Zn–air system. Prior to calculation, the ZnO is characterised by X-ray diffraction using Rietveld refinement. Diffracted patterns proved the formation of single phase ZnO, while Rietveld analysis shows that the ZnO has a hexagonal wurtzite structure with lattice parameters, a = 3.244 and c = 5.199 A. Geometry optimisation of the hexagonal wurtzite structure of the ZnO is performed using various exchange–correlation energy functionals. The local density approximation functional method is used to explain the structure, electronic band structure and density of state properties of hexagonal ZnO. The calculated energy band gap was 0.75 eV while the density of states reveals that the O 2p (the top valence band) and Zn 4s (the bottom conduction band) states domination.

0.5 wt.% of N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) was introduced into polymer electrolytes based on 30% poly(methyl-methacrylate) grafted natural rubber (MG30) in order to reduce the aging factor of MG30. The polymer electrolyte without 6PPD was used as control. All samples were prepared by using solution cast techniques. The effect of 6PPD in the electrolytes was analysed by using TGA, DSC and FTIR. TGA and DSC results revealed the thermal stability of MG30 electrolytes with 6PPD have higher thermal stability but lower glass transition temperature value. FTIR studies confirmed the existence of LiTF in the sample and prove the occurrence of polymer-salt complexation. Deconvolution techniques analysis on FTIR spectra shows the electrolyte sample with 6PPD display more ion dissociation which reflects to higher ionic conductivity.

Ferroelectric materials of lanthanum (La) doped PbZrTiO3 (PLZT) were investigated via first principles study. The structural, electronic and optical properties of PLZT in tetragonal structure (P4mm space group) were performed in the framework of density functional theory (DFT) with generalized gradient approximation (GGA) and local density approximation (LDA) methods. The calculated results of structural properties of PLZT were seen to be approximately close to the experimental data. The results of the electronic part were covered with the calculation of energy band gap and density of states (DOS). The highest valence band (VB) which lies at the Fermi level (EF) was dominated by the O 2p at F point. The conduction band (CB) of PLZT occurred at G point, which was primarily dominated by Ti 3d mixed at Pb and La p-state. Whereas the optical part was covered with the refractive index and absorption. The refractive index, n and the extinction coefficient, k were calculated with respect to photon energy. Those results obtained could be such a good prediction in studying parameters and properties of new materials.

Graphene is a material that has been heavily investigated in many researches due to its beneficial characteristics such as large surface area, low manufacturing cost, high electro conductivity and incredible mechanical strength. Applying the graphene in water-based solvents however can cause agglomeration due to its hydrophobic properties. Researchers have composited the graphene with other materials in overcoming its hydrophobicity. In this research, graphene was nanocomposited with thionine to make it disperse well in water-based solvents while preserving its intrinsic properties. The nanocomposition process involves mixing of both graphene oxide with thionine and were reduced by hydrazine hydrate while reflux heating. The produced mixture was then filtered to obtain the Thionine-Graphene nanocomposite. The obtained sample was then characterized to confirm the composition of both graphene and thionine. Fourier transfer infrared spectroscopy was operated to investigate the chemical bonds and hence concluding the presence of both graphene and thionine in the sample. The preservation of the intrinsic properties of graphene was also investigated through observing the absence of functionalized graphene bonds. Post-investigation reports that the chemical bonds from both of the materials, graphene and thionine were detected confirming the successfulness of the nanocomposition.

Proton exchange membrane materials based on sulfonated poly ether ether ketone (SPEEK) with Methyl Cellulose (MC) are developed by solution cast technique and exposed to UV radiation with Bezoin Ethyl Ether (BEE) as photoinitiator. The addition of MC into SPEEK polymer enhances the conductivity up to 8.7 × 10−3 Scm−1 at 30 °C temperature and 80% relative humidity. This new crosslinked hybrid membrane shows good prospect for the use as proton exchange membrane in fuel cell.

Objectives: The aims of this paper was to produce hydroxyl hypercrosslinked polymers with high specific surface area derived from poly(HEMA- co -EGDMA- co -VBC) precursor beads. Methods: This was achieved using hyper crosslinking reaction and the beads were characterized by FTIR, SEM and BET analysis. Findings: The BET analysis showed that specific surface area increasing from ~5 m 2 /g to 310 m 2 /g when amount of VBC increased up to 90 wt%. However, when amount of EGDMA increasing from 40 wt% to 100 wt%, specific surface area decreasing from 310 m 2 /g to ~61 m 2 /g. SEM images also showed that when increasing EGDMA content, hypercrosslinked polymer still can retain precursor shape with satisfied quality. The catalyst ratio was varied between 1:1 to 3:1 mole ratio (based on -CH 2 Cl content) and from the results obtained, there are no significant effect on specific surface area and morphology of hypercrosslinked polymer when ratio of catalyst increased. From FTIR spectra, reduction peak at 1265 cm -1 resulted from methylene bridges formed in all experiments proved that hypercrosslinking reaction was successfully carried out. Application/Improvement: Hypercrosslinked polymer will be used in functionalization reaction to produce quaternary ammonium resin.

This work aims to investigate effects of vanadium substitution on structural and electronic properties of the pristine LiFeSO 4 OH compound using GGA, GGA+U and GGA + van der Waals (vDW) dispersion corrections. Upon vanadium substitution, the band gap of substituted vanadium on LiFeSO 4 OH decreased implying the increase in electronic conductivity, thus a good property for a cathode material. Moreover, the volume of substituted material also increased suggesting ease movement of lithium ions within the host structure thus increasing the ionic conductivity. Since no experimental structure of this material has been reported, therefore the structure of current layered LiFeSO 4 OH is adopted. Furthermore, electronic properties viz. the lattice parameter, density of state (DOS), bond length (BL), bond order (BO) and charge density were also determined using the first principles approach.

First principles calculations on structural, electronic and optical properties of the orthorhombic phase (No. 62: Pnma space group) lead-free Sn(II) hybrid halide perovskite CH3NH3SnI3 were systematically carried out. Work on Pb(II)-based CH3NH3PbI3 hybrid halide perovskite of the same space group is also included for comparative purposes. All calculations were performed using the local density approximation (LDA) and the generalized gradient approximation (GGA) schemes. The obtained lattice parameters and cell volumes are consistent with the available experimental data and other theoretical works. According to the electronic band structure, both of the semiconductor compounds have a direct band gap. A band gap of 0.935 eV yielded for CH3NH3SnI3 compound, which is smaller compared to CH3NH3PbI3 (1.721 eV). In addition, we found that the optical absorption spectrum of the hybrid halide perovskite is red shifted with the reduction of the electronic band gap.

On the basis of ab initio calculation, we reported the structural and electronic properties of the nickel (Ni) substitution on the cobalt oxide (Co3O4) to produce nickel cobaltite (NiCo2O4) using generalized gradient approximation + U parameter (GGA + U) calculation method. The spinel NiCo2O4 with half-metallic behaviour has a relatively small band gap ∼0.64eV which is spotted decreased from pure Co3O4 band gap 1.26eV. This is due to nickel doping decreased the band gap which also implies that an increase in electrical conductivity. Owing to good electrical conductivity, NiCo2O4 thus enables to be considered for application in supercapacitor. Analysis of the partial density of states (PDOS) shows the differences contributions of cobalt (Co) at the tetrahedral site (Td) and Ni at the conduction bands: Co(Td) ions not affected the majority spin which is in contrast with Ni ions.

Structural, electronic and optical properties of nickel (Ni) doped bismuth selenide (Bi2Se3) in orthorhombic phase was studied via first principles approach using density functional theory (DFT). A generalized gradient approximation (GGA) for Perdew-Burke-Ernzerhof for solids (GGA-PBEsol) was employed as functional of exchange-correlation. The structural parameters of pure Bi2Se3 are in good agreement with the previous experimental and theoretical data. Calculated electronic properties of pure Bi2Se3 such as band gap is in agreement with the experiments. The effect of Ni has reduced the band gap of Bi2Se3 from 0.99 eV to 0.32 eV. Optical properties such as dielectric function was also calculated together with other optical properties and a comprehensive comparison was made. It was found that Ni-doping has contributed a better dielectric function, increased refractive index, and decreased extinction coefficient that provides many useful supports for technological applications. However, Ni-doping has caused slight deterioration of the absorption coefficient and the rise of a loss function.

The thin film of poly(methyl methacrylate) (PMMA) has been widely studied as host in a polymer electrolyte system due to its good mechanical stability towards lithium electrode. However, the brittle property of this film creates additional resistance for the ionic conduction. The addition of ionic liquid (IL) has been noticed to improve the brittleness of the film. In addition, its ionic conductivity can also be enhanced, but no free standing film can be obtained when higher amount of IL was added. Therefore, in this study, 1-methyl-3-pentamethyldisiloxymethylimidazolium bis(trifluoromethylsulfonyl)imide,[(SiOSi)C1C1im][NTf2], was incarcerated during free radical polymerization of MMA. Interestingly, this newly synthesized PMMA (PMMAIL) gives a flexible and transparent film with ionic conductivity of ∼10−7 S/cm at room temperature. The structural properties of this PMMAIL were further investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and optical microscope (OM).

In this study, first principles calculations based on density functional theory were used to evaluate optimized sructures and the total energy of the La doped PbTiO3 tetragonal (P4mm phase group). The calculations were conducted using local density approximation (LDA) functional as implemented in Cambridge Serial Total Energy Package (CASTEP) computer code. The different composition of Lanthanum (x) were doped on PbTiO3 resulting Pb1-xLaxTiO3 and its effect on the structural of Pb1-xLaxTiO3 were investigated. The different composition of La changed the lattice parameter and the volume of Pb1-xLaxTiO3. The total energy also were calculated and x= 0.2 is suitable composition of dapant to doped with PbTiO3 which is more stable compared with the other composition. The results are compared with experimental and other theoretical data.

In this paper, the effect of substitution of Co by d-valent elements such as Ag and Pt on electronic structure and magnetic properties of full Heusler type Co2FeSi alloys was investigated. Structural study reveals the presence of a small gap in the minority band structure around the vicinity of the Fermi level on Co2FeSi resulting to half-metallic behaviour. However, CoFeSiAg and CoFeSiPt cannot preserved the half-metalicity due to disappearing of the gap in the minority band structure due to the creation of new states around the Fermi level in the minority density of states. The variation in the magnetic moment of Co2FeSi with change of the atoms was attributed to the change in the local magnetic moment of atoms.

A new carbon material viz. graphene has been attracted an increasing research interest owing to its unique electrical and mechanical properties that is useful for the various device applications. The synthesis of graphene from graphene oxide usually involves harmful chemical reducing agents that are toxic and undesirable to human and the environment. By avoiding the use of toxic and environmentally harmful reductants, we report a green approach to effectively reduce graphene oxide to graphene in glucose solution at room temperature. Graphite oxide was synthesized from graphite powder using modified Hummers’ method. Graphite oxide then further exfoliated to graphene oxide by using ultrasonic irradiation. The mild reduction of graphene oxide is carried out by mixing graphene oxide solution with glucose. The reduction time is varied with 15, 30, 45 and 60 minutes. TEM images provide clear evidence for the formation of few layer graphene. Characterization of theresulting glucose reduced graphene oxide by FTIR indicates the partial removal of oxygen-containing functional groups from the surface of graphene oxide and formation of graphene with defects.

The effect of lithium intercalation on the structural and electronic properties of layered LiFeSO4OH and layered FeSO4OH cathode material is investigated using first-principle calculations. Results of Mulliken analysis, band gap, density of state, and charge density before and after intercalation are discussed. The importance of the strong covalent character of S–O and Fe–O bonds in high charge/discharge cycles and thermodynamic stabilities is confirmed. Analysis of the partial density of state reveals that the main contributor to the strong S–O covalent bond is the hybridization between the S 3s, S 3p electron state and the O 2p electron state. The Fe 3d orbital also plays an important role in cathode performance because it dominates the conduction and valence bands and radically changes upon the removal and insertion of lithium ion inside the cathode materials. The charge density elucidates the ionic and covalent characters of the bond inside the cathode.

Effect of glucose loading on the synthesis mesoporous carbon had been studied using hard template method where mesoporous silica SBA-15 was used as a template. To obtain a large pore of mesoporous carbon sample, a large pore of silica template was used. A series of mesoporous carbon sample was synthesized by loading different amounts of glucose (2.5g, 5.0g and 10.0g) as a carbon precursor to ensure that the template was fully impregnated with precursor. After treatment process, the surface area of carbon samples were measured with Brunauer-Emmett-Teller (BET) analysis and it shows that higher amount of glucose gives higher surface area due to the large pore of the template used. The samples then were tested with cyclic voltammetry technique at different scan rates (10, 20, 30 and 50 mVs-1) in 6M KOH electrolyte. It reveals that higher surface area samples show a higher specific capacitance with 119 F/g at slow scan rate 10 mVs-1.

First Principles Calculation of e-Phase of Solid Oxygen K.H. Kamaruddin, A.F.Z. Abedin, N.A. Zabidib,∗, M.Z.A. Yahya, M.F.M. Taib and A.N. Rosli Defence Science Department, Faculty of Defence Science and Technology, Universiti Pertahanan Nasional Malaysia, Kuala Lumpur 57000, Malaysia Physics Department, Centre for Defence Foundation Studies, Universiti Pertahanan Nasional Malaysia, Kuala Lumpur 57000, Malaysia Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia Faculty of Science and Technology, Universiti Sains Islam Malaysia, Nilai 71800, Negeri Sembilan, Malaysia

In this study, gel polymer electrolytes (GPEs) system is prepared by the solution cast technique. The system consists of cellulose acetate (CA) as a host polymer, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as a dopant salt and diethylene glycol dibutylether (BDG) from glyme based family as a plasticizer. GPEs (65 wt. % CA–25 wt. % LiTFSI–10 wt. % BDG) sample is the highest conductivity of 2.88×10-3 S.cm−1 at room temperature. The lithium-electrolyte interfaced stability is established and the highest ionic conducting electrolyte is able to withstand up to 3.8V vs Li/Li+.

The geometry optimization of the tetragonal supercell 1x1x2 (P4mm, 99 space group) of PZT and PSnZT were calculated using different exchange correlation functional such as Local Density Approximate (LDA-CAPZ) and Generalized Gradient Approximation (GGA-PBE & GGA-PBEsol).The calculation using functional GGA-PBEsol exhibits the most accurate values of lattice parameter and volume of structure relative to the experiment results with typical error of approximately 1% underestimate (only for PZT-as reference materials). The electronic band structure and density of state (DOS) were also studied in order to understand the electron density and hybrization between cation and anion in the compound. The density of state studies indicated existing of hybridizations among anion O 2p, cation Pb 6s/Sn 5s (special lone pair) and the Ti 3d/Zr 4d states of PZT and PSnZT compound. An indirect band gap was respectively obtained for both cubic PZT and PSnZT at the F-G and Q-G point with 3.154 eV and 2.571 eV.

First-principles study based on density functional theory (DFT) framework for structural, electronic and optical properties of titanium dioxide (TiO2) in anatase and rutile phases are investigated. Anatase phase exhibits wide band gap compare to rutile phase. The partial and total density of states for TiO2 (anatase and rutile) describes the occupying of titanium (Ti) and oxygen (O) atoms at each energy level. TiO2 has a high dielectric constant to avoid the recombination process while its high refractive index provides the efficient of light diffusion. The optical absorption of TiO2 occurs in ultraviolet (UV) light of the wavelength photon. The results from the first-principles calculations will be helpful to give an understanding about the properties of TiO2 as promising photoanode in dye-sensitized solar cell (DSSC).