Electrophoretically deposited TiO2 compact layers using aqueous suspension for dye-sensitized solar cells

Abstract

TiO₂ compact layers (CLs) prepared by electrophoretic deposition (EPD) from an aqueous nanoparticle suspension were used in dye-sensitized solar cells (DSSCs) to prevent charge recombination at the interface between the transparent fluorine-doped tin oxide (FTO) substrate and the electrolyte. The TiO₂ nanopowder (ca. 4.5 nm diameter) suspension used in the EPD process was prepared via a continuous hydrothermal flow synthesis pilot plant (at a production rate of ca. 0.38 kg h⁻¹). The optimal thickness of the TiO₂ CL for DSSCs is about 115 nm. Compared to the DSSCs without a CL, the optimal cell has shown improved short-circuit current density (J_SC) and solar energy conversion efficiency by 13.1% and 15.0%, respectively. The mechanism for improved performance has been studied by the measurements of dark current and electrochemical impedance spectra. The interfacial charge transfer resistance at the FTO/electrolyte interface is increased after fabricating a CL in the cell, indicating inhibited electron recombination at the interface.