Electrophoretic deposition of TiO2 coatings for use in all-plastic flexible dye-sensitized solar cells

• Electrophoretic deposition of TiO2 photoanode was performed at a low electric field of only 20 V cm− 1.
• Based on the deposition kinetics, the structure of the TiO2 photoanode was engineered.
• The photoanode structure was optimized for the optical properties and cell performance.
• Efficiency reached a peak of 5.23% for the resulting flexible dye-sensitized solar cell.
• An ultrafast electron diffusion time as rapid as 0.34 ms is demonstrated.

For the use in all-plastic flexible dye-sensitized solar cells (DSSCs), various TiO2 photoanodes having different structures were prepared using commercial P25 and ST41 powders. The photoanodes were deposited using an electrophoretic deposition (EPD) technique, followed by a mechanical compression. The deposition kinetics of the EPD photoanode formation was first studied. Based on the deposition kinetics, various photoanode structures consisting of P25, ST41, or a mixture of P25 and ST41 powders were made and characterized. The photoanodes were then evaluated for use in all-plastic flexible DSSCs. The effect of the photoanode structure on the cell performance, including electron transport property, was investigated and discussed. Optimized photoanode structure is reported as a result.