Single- and double-layered mesoporous TiO2/P25 TiO2 electrode for dye-sensitized solar cell

Nanocrystalline mesoporous titania (MP-TiO₂) was synthesized by surfactant-assisted templating method using tetraisopropyl orthotitanate modified with acetylacetone and laurylamine hydrochloride as template. The short-circuit photocurrent density (J_sc) of the cell made from MP-TiO₂ was much higher than that of the cell made from commercial P25 titania. The incident photon to current conversion efficiency (IPCE) spectra of thin MP-TiO₂ cell were higher than that of thick P25 cell in the region between 400 and 475 nm but lower than that of thick P25 cell in the red region, because the thickness of thin transparent MP-TiO₂ film was not enough to scatter the light leading to low absorbed spectra in red region. IPCE spectra of MP-TiO₂ can be improved by using the cell made from blended MP-TiO₂ with P25. The cell performance was improved with increasing sintering temperature. Double-layered titania cells were also fabricated to further improve the cell performance by increasing light scattering and amount of adsorbed dye. The solar energy conversion efficiency (η) up to 8.1% was obtained by using the double-layered titania cell sintered at 450 °C for 2 h.