Formation of efficient dye-sensitized solar cells by introducing an interfacial layer of hierarchically ordered macro-mesoporous TiO2 film

Hierarchically ordered macro-mesoporous TiO2 films (Ti-Ma-Me) were fabricated on fluorine-doped tin oxide (FTO) substrates through the confinement self-assembly method. The prepared Ti-Ma-Me possesses periodically ordered structure and a large specific surface area, which was applied as an interfacial layer between the nanocrystalline TiO2 film (P25-TiO2) and FTO electrode in the dye-sensitized solar cell (DSSC). The introduction of a Ti-Ma-Me interfacial layer increased the shortcircuit current density (J (sc)) from 7.49 to 10.65 mA/cm(2) and the open-circuit voltage (V (oc)) from 0.65 to 0.70 V as the result of its improved light harvesting efficiency by allowing for the high roughness factor and enhanced multiple internal reflection or scattering as well as reducing the back-transport reaction by blocking direct contact between the electrolyte and FTO electrode. Therefore, the photovoltaic conversion efficiency (eta) was improved by 83% from 3.04% to 5.55%, as compared to a device using a bare P25 TiO2 photoanode.