Repository logo

Research Articles (Mechanical Engineering)

Permanent URI for this collectionhttps://hdl.handle.net/10413/6864

Browse

Browsing Research Articles (Mechanical Engineering) by Author "Eloka-Eboka, Andrew Chukwudum."

Filter results by typing the first few letters
Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Experimental optimization of nanostructured nickel oxide deposited by spray pyrolysis for solar cells application.
    (Research India Publications., 2018) Ukoba, Kingsley Ogheneovo.; Eloka-Eboka, Andrew Chukwudum.; Inambao, Freddie Liswaniso.
    Abstract available in PDF file.
  • Thumbnail Image
    Item
    Experimental optimization of nanostructured nickel oxide deposited by spray pyrolysis for solar cells application.
    (Research India Publications., 2018) Ukoba, Kingsley Ogheneovo.; Inambao, Freddie Liswaniso.; Eloka-Eboka, Andrew Chukwudum.
    This study focused on the experimental optimization of nanostructured nickel oxide (NiO) for solar cell applications. The optimization procedure involved the variation of the precursor concentrations of nickel acetate with attendant measurement of the properties of nickel oxide films. The films were spray deposited on glass substrate. Nickel acetate precursor was used at a substrate temperature of 350 oC. Precursor concentrations were: 0.025 M, 0.05 M, 0.075 M and 0.1 M respectively. The surface morphology revealed nanostructured film with particles densely distributed across the substrate’s surface. The films are homogeneous, smooth, well adherent and devoid of pinholes and cracks. The morphology became grainier as the precursor solution increased. Elemental composition exposes the presence of Ni and O elements in NiO film. Oxygen concentration decreases as precursor solution increases. The film structural property reveals that deposited NiO film has an amorphous structure at 0.025 M while the other concentrations are polycrystalline in nature with cubic structure. X-ray diffractometry (XRD) further reveals that the intensity of NiO films increases with increased molarity. Preferred orientation was along the (1 1 1) peak with minor intensity along the (2 0 0) peak. XRD patterns have peak diffraction at (2θ = 37 o and 43 o) for the (1 1 1) and (2 0 0) planes respectively, and 64 o for the (2 2 0) plane for 0.1 M. Crystallite size was obtained at 63.77 nm maximum. Film thickness increased with increasing precursor concentration from 6.277 μm to 11.57 μm. Film micro strain was observed to have compression for all precursor solutions. Optical studies showed that transmittance decreased with increasing concentration from 80 % to 71 %. Optical band gap energy was between 3.94 eV to 3.38 eV as precursor concentration increased, revealing the effect of varied concentrations on NiO film properties. Optimized results obtained are precursors in the development of low cost, efficient, durable solar cell fabrication for developing countries.
  • Thumbnail Image
    Item
    Fabrication of affordable and sustainable solar cells using NiO/TiO2 P-N heterojunction.
    (Hindawi., 2018) Ukoba, Kingsley Ogheneovo.; Inambao, Freddie Liswaniso.; Eloka-Eboka, Andrew Chukwudum.
    The need for affordable, clean, efficient, and sustainable solar cells informed this study. Metal oxide TiO²/NiO heterojunction solar cells were fabricated using the spray pyrolysis technique. The optoelectronic properties of the heterojunction were determined. The fabricated solar cells exhibit a short-circuit current of 16.8 mA, open-circuit voltage of 350 mV, fill factor of 0.39, and conversion efficiency of 2.30% under 100mW/cm² illumination. This study will help advance the course for the development of low-cost, environmentally friendly, and sustainable solar cell materials from metal oxides.
  • Thumbnail Image
    Item
    Influence of concentration on properties of spray deposited nickel oxide films for solar cells.
    (Elsevier., 2017) Ukoba, Kingsley Ogheneovo.; Eloka-Eboka, Andrew Chukwudum.; Inambao, Freddie Liswaniso.
    Spray pyrolysis technique was used to deposit various concentration of nickel oxide films on glass substrate. The Effect of varying precursor concentration on elemental, morphological and structural properties was investigated on the deposited NiO films. Nickel (II) acetate tetrahydrate precursor was used at substrate temperature of 350 oC. Precursor concentrations were 0.025, 0.05, 0.075 and 0.1 M. Scanning Electron Microscope (SEM) surface morphology revealed nanostructured films with particles densely distributed across substrates surface. Increased in surface grains was observed as the precursor solution increased. Elemental composition of NiO films revealed presence of Ni and O element. There was reduction in oxygen concentration as precursor solution increases. Amorphous structure was observed at concentration of 0.025 M while polycrystalline with cubic structure was observed at higher concentrations. Preferred orientation was along (1 1 1) peak with small intensity along (2 0 0) peak. XRD patterns have peak diffraction at (2θ = 37 o and 43 o) for (1 1 1) and (2 0 0) planes respectively and 64 o for (2 2 0) plane for 0.1 M. Film thickness grew with increase in precursor concentration. Film micro strain was observed to have compression for all precursor solution conspicuously revealing the effect of varied concentration on NiO films properties