Browsing by Author "Shikangala, Ingrid Panduleni"

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    Synthesis and characterisation of thiophene based metal free dye sensitisers for solar cells, their photo-response and chemosensing properties
    (University of Namibia, 2020) Shikangala, Ingrid Panduleni
    In 1991, Michael Grätzel and co-workers developed a new photovoltaic cell known as Dye Sensitized solar cells (DSSCs); these photovoltaic semiconductor devices convert solar radiation directly into electricity [1]. Metal-free sensitizers such as organic dyes and natural dyes have received attention as alternative DSSC applications and have been extensively developed [2]. Two metal free dyes were reported. These dyes were prepared through Schiff base synthetic methods, which are easy to follow. The dyes absorb light in the visible light region. The interaction with ionic other species (sensing) properties were studied, with dye I1 (sensor A) and dye I2 (sensor B) designations. These recognition properties towards various ions were investigated firstly by naked eye observation and secondly by spectroscopic methods such as UVvis in water-soluble DMSO. As a result, the addition of mercury (Hg2+) to sensor A displayed a clearly visible “naked eye” detectable colorimetric activities (from yellow to pale yellow), while the addition of fluoride (F-) and cyanide (CN-) to sensor B also displayed "naked eye" detectable colorimetric activities (from pink to purple), in DMSO at ambient temperature. Thus each dye possesses a duality function, as an organic DSSC as well as a colorimetric sensors for discriminating specific ionic species in a given environment.