OPTICAL BAND GAP EXCITATION AND PHOTOELECTRON GENERATION IN TITANIUM DIOXIDE-BASED SOLID STATE SOLAR CELLS

The properties and optical band gap excitation of nanoporous titanium dioxide (TiO2) and transparent semiconducting copper iodide (CuI) films prepared by a XeCl excimer laser were investigated. The CuI films exhibited optical transmittance over 80% in the wavelength range from 400 to 900 nm with minimum resistivity of about 2 KΩcm. The optical absorption of these films showed a remarkable blue shift compared to that of polycrystalline of CuI, which can be explained from the formation of ultra fine of CuI grains. The properties of pulsed laser deposited CuI and TiO2 in power output of p-CuI|dye|n-TiO2 cells were studied. The photoelectron generation and mechanism in fabricated p-CuI|dye|n-TiO2 cells were also studied. An efficient charge generation was observed through the illumination of the TiO2 layer of the fabricated p-CuI|dye|n-TiO2 cells. The band gap excitation of TiO2 was observed only under illumination through TiO2 layer. The adsorbed dye molecules to the TiO2 surface act as a relay, especially under illumination through TiO2 layer in the wave range region of 300–400 nm.