Applied Mechanics and Materials Vols. 754-755

Abstract: In this paper, the contribution of Indium (In) to the Gallium Phosphide (GaP) composition of solar cell was investigated to know the effectiveness of the In when its being substitute to GaP layer on the top layer of Silicon (Si) substrate. The substitution was made to the Ga_1-xIn_xP for the range of (0≤x≤0.5). The highest efficiency was 10.1235% for x=0.5 for the Ga_1-xIn_xP. In contribution shows a higher efficiency compared to single layer GaP which only about 5.40608%. As the x composition increased, the efficiency becomes higher for each composition increment. The rate of efficiency, increased about 88% and improves current density with a value up to 13.1134mA/cm².The efficiency obtained in this work is considerably high using simulation tools compared to the previous record for InGaP/Silicon reported in Feb 2014 about 6~11.2% by fabrication method.

Abstract: The layered rock salt LiNi_0.7Mn_0.3O₂ was prepared by conventional solid-state synthesis route. The prepared samples were analysed using X-ray diffraction (XRD) to determine purity of samples. Then, structural analysis and crystallographic properties of samples were analysed using Rietveld refinement. Rietveld refinement results indicated that the amount of cation disorder in the layered rock salt structure highly influenced by temperature and synthesis conditions. The most optimum temperature to obtain the highest degree of cation ordering is between 850^oC and 900^oC in air.

Abstract: Titanium Dioxide (TiO₂) layer was deposited on conductive transparent glass substrate (ITO glass) at room temperature using doctor blade method. The TiO₂ layer was annealed at 450 °C, 550 °C and 650 °C in a vacuum chamber for 1 hour. The morphology and porosity of TiO₂ after annealed at different temperatures were characterized using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Spectrum Parameter Analyzer (SPA). Photocatalytic activity at different annealing temperatures was measured for dye sensitized solar cell that was fabricated using the new in-house carbon nanotubes-graphene hybrid as the dye material. The results showed that, the optimum annealing temperature was 450 °C. At that temperature, the active photocatalytic activity, which was initiated by the anatase TiO₂ formation in paired with hybrid system as the working electrode, has contributed to the highest conversion efficiency of 0.0016% of the device performance.

Abstract: Carbon (C) and Nitrogen (N) modified TiO₂ photocatalysts were prepared by using two different precursors namely peat and urea using commercial TiO₂-P25. The results from HR-TEM and XPS analyses shows different interactions between C-TiO₂ and N-TiO₂ photocatalysts where C is only coated on top of TiO₂ while N is chemically bonded in TiO₂ particle. Higher photocatalytic activity for both C and N modified TiO₂ were observed under degradation of reactive red 4 dye (RR4) with the degradation rate were c.a 2.5 and 2.7 times faster compared with pristine TiO₂. The photoluminescence (PL) analysis data showed the lowest PL intensity over C coated TiO₂ followed by pristine TiO₂ while N doped TiO₂ exhibited the highest PL intensity. The lowest PL intensity of C coated TiO₂ was due to the presence of C as electron acceptor while the highest PL intensity for N doped TiO₂ was due to the oxygen vacancies and TiO₂ defect structure.

Abstract: The photocatalytic degradation of 4-Chlorophenol (4CP) using carbon C coated TiO₂ (C-TiO₂) and pristine TiO₂ under solar irradiation was carried out in a suspension mode under custom made glass cell reactor with continuous aeration supply. It was found that 0.3 and 0.6 g were the optimum loading for C-TiO₂ and pristine TiO₂ respectively in the degradation of 20 mg L^-1 4CP under solar irradiation. The optimum C-TiO₂ was found six times faster than pristine TiO₂ based on pseudo first order rate constant of 4CP photodegradation. No adsorption was observed in the photocatalysts. The intermediates observed during this photocatalytic degradation process were maleic acid, hydroquinone (HQ), benzoquinone (BQ), 4-chlorochetol (4CC) and resorcinol.