Electrospun TiO2 nanofiber based hierarchical photoanode for efficient dye-sensitized solar cells

The development of effective photoanode materials with hierarchical architecture provides a promising scheme to fabricate efficient energy conversion devices. In this manuscript, we report the synthesis of a novel hierarchical nanorod-branched TiO2 nanofiber non-woven fabric film and its photoelectric performance as photoanode material for dye-sensitized solar cells (DSSCs) is investigated. The synthesis process involves transferring electrospun TiO2 nanofibers film completely to the surface of fluoride-doped tin oxide (FTO) glass substrate first, and a followed hydrothermal treatment to grow hierarchical TiO2 nanorod branches. The photovoltaic tests reveal that the DSSCs based on such hierarchical photoelectrode exhibit an impressive power conversion efficiency (eta) of 6.26% under AM 1.5 G one sun illumination with greatly improved short-circuit current density (J(sc)) compared to pristine TiO2 nanofibers film. The enhanced efficiency is a direct consequence of the synergistic effect of improved light harvesting efficiency induced by high dye loading and superior broadband light scattering effect and fast charge transport of composite structure, which are characterized in detail by UV-vis diffuse reflectance spectra, electrochemical impedance spectra (EIS), open-circuit voltage-decay (OCVD) measurement, intensity-modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS). These results indicate the electrospun non-woven fabric films based nanomaterials can work as excellent photoelectrode candidates for DSSCs, or other photoelectric applications. (C) 2015 Elsevier Ltd. All rights reserved.