Post-treatment on dye-sensitized solar cells with TiCl4 and Nb2O5

Abstract

Post-treatment of TiCl₄ improves the overall conversion efficiency of dye-sensitized solar cells by enhancing the photocurrent (J_SC) rather than the photovoltage (V_OC), owing to an 80 mV downward shift in the TiO₂ conduction band edge potential. Further treatment with niobium isopropoxide forms a Nb₂O₅ barrier layer that induces an upward shift in the Fermi energy and decreases the recombination rate, resulting in larger V_OC. Quite intriguingly, the incident photon to current conversion efficiency results show that this second treatment also enhances J_SC. Thus, the resulting electrode shows an improved conversion efficiency (by ca. 52%) over that of the non-treated electrode.