Performance Enhancement Of Silver-Nanoparticle/Titania (Ag-Np/Tio2) Using Chlorophyll As Dye Sensitizer

ABSTRACT

Titanium dioxide or titania (TiO2) being one of the most promising semiconductors for many photoelectrochemical applications, its utilization remains typically confined to ultraviolet (UV) light absorption because of its wide band gap (3.2 eV for anatase and 3.0 eV for rutile), where by UV only accounts for 4-6% of the solar radiation. There is a need to shift the absorption threshold of the UV-region response of TiO2 into the visible region (accounts for ~45% of the total energy of the solar radiation), which can be achieved by doping TiO2 with dye sensitizers, non-metals, transition metals or through surface plasmon resonance (SPR) using noble metals. To study the absorption spectra of metallic silver nanoparticle/titania/Chlorophyll (Ag-NP/TiO2/Chlorophyll) thin films, sandwich arrangement thin films were fabricated on a quartz glass substrate at 550°C using a spin coater. Respective precursor solutions for Ag-nanoparticles and titania were prepared from Ag salt and a titanium complex using molecular precursor method. The Chlorophyll dye was extracted from the Colophospermum mopane leaves (Mopane tree leaves) and Hyphaene petersiana leaves (Makalani tree leaves) using methanol as a solvent extract. The Ag-nanoparticle/TiO2 (Ag-NP/TiO2) thin films were then immersed in the Chlorophyll dye for 48 hours, to produce Ag-NP/TiO2/Chlorophyll dye composites thin films. A Fourier-transform infrared (FTIR) spectrum was used to confirm whether the dye extract was chlorophyll.