Increasing photocurrents in dye sensitized solar cells with tantalum-doped titanium oxide photoanodes obtained by laser ablation.

Laser ablation is employed to produce vertically aligned nanostructured films of undoped and tantalum-doped TiO(2) nanoparticles. Dye-sensitized solar cells using the two different materials are compared. Tantalum-doped TiO(2) photoanode show 65% increase in photocurrents and around 39% improvement in overall cell efficiency compared to undoped TiO(2). Electrochemical impedance spectroscopy, Mott-Schottky analysis and open circuit voltage decay is used to investigate the cause of this improved performance. The enhanced performance is attributed to a combination of increased electron concentration in the semiconductor and a reduced electron recombination rate.