Electrophoretic deposition of TiO2 nanorods for low-temperature dye-sensitized solar cells

Abstract

The fabrication of low-temperature photoanodes is essential for flexible dye-sensitized solar cells. Electrophoretic deposition (EPD) represents a potential alternative to form photoanodes at low temperature. To optimize the photoanodes fabricated by EPD, TiO₂ nanorod/nanoparticle (labeled as NRP) structures were synthesized. The obtained NRPs have high surface charges and wide size distribution, making them suitable to form binder-free photoanodes with EPD. Compared with reference DSSCs produced with P25 (commercial TiO₂ particles), NRP based DSSCs showed enhanced light-scattering property and decreased recombination. Further, under the same total time, the efficiencies of the devices obtained with multiple EPD are above 2.2 times those of one step devices. Without any calcination or compression, the best device (with multiple EPD and a thin layer of nanoparticles) gives a conversion efficiency of 4.35%, having a short circuit current density, open circuit voltage, and filling factor of 8.41 mA cm⁻², 0.74 V and 69.75%, respectively.