Effi ciency of dye sensitized solar cells with various compositions of TiO2 based screen printed photoactive electrodes

The TiO₂ electrode has a key role in dye sensitized solar cell (DSSC) technology in the charge generation and charge transportation. The properties of TiO₂ layer affect resulting efficiency of DSSC and can be controlled by printing process and chemical composition of printing paste. TiO₂ pastes with different compositions of TiO₂ nanoparticles, ethanol, ethyl cellulose, water, acetic acid, α-terpineol were prepared and screen printed onto the glass substrate with fluorine doped tin oxide (FTO). The TiO₂ pastes for screen printing were characterized by rheological measurements and screen printed TiO₂ electrodes by atomic force microscopy and UV-Vis spectroscopy. The photocurrent - voltage characteristics and efficiencies of DSSC were evaluated and compared. All prepared TiO₂ pastes were suitable for screen printing with ideal rheological characteristics. The highest efficiency 0.68 % and current density I_SC = 1.21 mA/cm² reached by the DSSC based on TiO₂ electrode with thickness 1.5 μm, with amount of absorbed dye 1.1 × 10^-8 mol/cm² and without visible cracks and particles aggregation. This TiO2 electrode was prepared from the paste containing 5.4 wt. % of TiO₂, 65.3 wt. % of ethanol, 1.8 wt. % of ethyl cellulose, 23 wt. % of H₂O and 4.5 wt. % of CH₃COOH.