Integrated Electronic, Optical, and Structural Features in Pseudo-3D Mesoporous TiO2-X Delivering Enhanced Dye-Sensitized Solar Cell Performance.

ABSTRACT

The performance of a dye-sensitized solar cell (DSSC) is strongly affected by optical, structural, and electronic features of a photoanode. In this article, meso-TiO2-X was prepared by a solution combustion method and hydrogenation at high pressure. The properties of DSSCs with meso-TiO2-X photoanodes were investigated by photocurrent-voltage, incident photon-to-current conversion efficiency, and electrochemical impedance spectroscopy (EIS) measurements. The meso-TiO2-X materials exhibit new electronic states and aided to absorb in the visible region because of the narrow band gap. Facile charge transfer from the N719 dye to the TiO2 photoanode was assisted by low-lying mid-gap states. Electrically integrated nanoparticles, with a small-channel mesoporous framework, facilitates fast charge transport across the material. Furthermore, EIS has shown that chemical capacitance, recombination resistance, and electron lifetime were affected by hydrogenation, thus indicating an effect on the photoanode material charge dynamics of DSSCs. An η of 7.2% under AM 1.5G illumination is obtained and an improvement by 75.6% over Degussa P25 titania. This is attributed to improved light harvesting and charge collection by the meso-TiO2-X photoanode obtained via simple combustion synthesis.