Enhancing the performance of dye-sensitized solar cells based on TiO2 nanotube/nanoparticle composite photoanodes

Abstract Improved efficiencies in quasi solid-state and liquid state dye-sensitized solar cells (DSSCs) are achieved by constructing TiO 2 -based photoanodes with nanostructures of nanotubes (NTs) and nanoparticles (NPs). High surface area, high quality, and good crystallinity of TiO 2 NTs were synthesized through a simple reflux method by using commercial P25 NPs as a precursor. The highest conversion efficiency was investigated while the composite photoanode composed of the mixture of 10% (v/v) NTs in NPs, where assembled DSSCs exhibited the conversion efficiency of 2.4% in PEGDME-based electrolyte and 10.27% in DMPII-based liquid electrolyte, with TiO 2 composite thickness of 6 μm and 12 μm, respectively, which showed improved conversion efficiency by 20.6% and 10.5% as compared to that of pure TiO 2 NP DSSC. Electrochemical impedance spectra (EIS) demonstrate that TiO 2 NTs are beneficial to improve the electron transport property as well as possess high charge collection and light harvesting and thus lead to the enhancement of the conversion efficiency.