Anodized nanoporous Nb2O5 films are synthesized using two different types of electrolyte compositions onto transparent conductive glasses and their impurities induced during the anodization process are assessed. These films are incorporated as photoanodes in dye sensitized solar cells (DSSCs). The one with no traces of impurity-driven defects exhibits higher current density and longer electron lifetimes, and consequently, an improvement in photoconversion efficiencies compared to the one that contains impurities.