RP-Department of Physics

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Browsing RP-Department of Physics by Subject "Absorption"

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    Effect of the use of inorganic- based photoluminescent materials in solar energy devices application
    (WJAETS, 2023) Kimemia, D. Njoroge; Njoroge, W. K.; Mwangi, I.W.; Tonui, M
    The dynamic processes that take place in life require energy. The main convenient source of energy even in living tissue are hydrocarbons. This is due to the high-carbon based energy source that eventually converts fossil fuels. The preferred fuels as the primarily and industrial fuel contribute to the observed negative effects which emit pollutants to our environments and result to global warming. To mitigate such energy dependence, solar radiation has been exploited to produce clean energy through the use of photovoltaic cells. Nevertheless, natural radiation varies depending on the season of the year. This study investigated the properties of inorganic materials that support fluorescence after the source of light has been withdrawn. The minerals Sb/Ca/Mn/Ag were prepared hydrothermally to cultivate luminescent properties. The resulting products were characterized using Fourier Transformed Infrared (FTIR) spectroscopy and then applied to extend radiation in a photoactive material of a photocell. Optimal values of the prepared luminescent substance were established to produce the best generated potential in the fabricated solar cells when the natural radiation was withdrawn. Established receptive layer composites (KI/I2: CX) were inserted into a molding dice on top of the photosensitive layer and joined together by pressing. The ensued inorganic luminescent cells optical characteristics were observed under UV radiation (320 - 400 nm) wavelength which produced sequential varying colorations from brown, light blue, blue to red before diminishing gradually as the incident radiation was removed. The open circuit potential voltage (VOC) and current density (JSC) generated parameters were observed. The (0.45, 0.4, and 0.086) V residue potential resulted due to shifting of IR by SbNO3, Sb-PO4, Sb-CO3 and Sb-O luminescent materials. The dopants had promising properties for radiation delay in photo voltaic devices application.
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    Influence of Localized Surface Plasmon Polaritons on Silver Nanoparticles
    (ABC Journal of Advanced Research, 2020) Mosiori, Cliff Orori; Njoroge, Walter Kamande; Ochoo, Lawrence Otieno
    In this article, we present a theoretical study on localized surface Plasmon of spherical Ag nanoparticles (NPs) done by numerical simulation. A plane EM wave was used to determine absorption cross-section and results showed that excitation of LSPPs produced an electric field on the surface of the nanoparticle. This field causes a large cross sectional area that influences higher scattering of incident photon at the surface of an absorber layer. It was concluded that LSPPs excitations in small size spherical particles can be utilized in low-cost solar cells to increase PCE of solar panels and can be expanded to many other fields of optoelectronic technologies ranging from solar cells, through photo diodes to optical bio-sensing applications.