A novel antireflective TiO₂ compact layer (arc-TiO₂) that can reduce electron recombination and improve transmittance was deposited by RF magnetron sputtering at the interface between indium tin oxide and porous-TiO₂layer of a dye-sensitised solar cell (DSSC). Effects of the arc-TiO₂ thicknesses on the performance of the arc-TiO₂-based DSSC were investigated by means of incident photon-to-current efficiency (IPCE), open-circuit voltage decay (OCVD) and electrochemical impedance spectroscopy (EIS). The sensitisation effect of N719 dye was remarkably improved due to relatively higher and red-shifted transmittance spectra of the ITO/arc-TiO₂ electrode in a specific region, and evidenced by the IPCE measurement. Meanwhile, the slow decay behaviours of the photo-voltage owed to the compact layer were verified by the OCVD measurement. The adhesion enhancement between the arc-TiO₂ film and porous-TiO₂ layer decreases the interfacial resistance R₁ in the EIS measurement, hence facilitating the charge transfer process of the electrons in the DSSC. A significant improvement in the overall solar energy-to-electrical conversion efficiency, which constituted almost 50% higher compared with the uncoated ITO cell, is mainly attributed to the higher transmittance and reduced recombination of the arc-TiO₂ film employed as the tri-functional compact layer in the DSSC.