Enhancing the photovoltaic performances of dye-sensitized solar-cells by modifying the TiO2 electrode-sensitized dye interface

Enhanced photovoltaic performances of N719 dye-sensitized solar-cells were achieved by modifying the titanium oxide (TiO2) electrode-sensitized dye interface. Surface of TiO2 thin film electrode was coated with a calcium oxide (CaO) or lithium fluoride (LiF) thin layer, respectively, in a thermal deposition chamber. As compared to a cell using a bare TiO2 nanoparticle (NTP) electrode, the solar energy conversion efficiency (η) was enhanced by 15.1% and 12.8% for the surface of a NTP electrode coated with CaO and LiF, respectively. Moreover, for the surface of a TiO2 nanotube electrode respectively coated with CaO and LiF, the efficiency was enhanced by 4.8% and 11.6%. This increase in efficiency is attributed to an increase in the adsorption of N719 dye on the CaO or LiF coated TiO2 thin film electrodes, and the formation of a potential barrier by a CaO or LiF interlayer at the TiO2 electrode-sensitized dye interface.