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

Abstract

The TiO 2 electrode has a key role in dye sensitized solar cell (DSSC) technology in the charge generation and charge transportation. The properties of TiO 2 layer affect resulting efficiency of DSSC and can be controlled by printing process and chemical composition of printing paste. TiO 2 pastes with different compositions of TiO 2 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 TiO 2 pastes for screen printing were characterized by rheological measurements and screen printed TiO 2 electrodes by atomic force microscopy and UV-Vis spectroscopy. The photocurrent - voltage characteristics and efficiencies of DSSC were evaluated and compared. All prepared TiO 2 pastes were suitable for screen printing with ideal rheological characteristics. The highest efficiency 0.68 % and current density I SC = 1.21 mA/cm 2 reached by the DSSC based on TiO 2 electrode with thickness 1.5 μm, with amount of absorbed dye 1.1 × 10 -8 mol/cm 2 and without visible cracks and particles aggregation. This TiO2 electrode was prepared from the paste containing 5.4 wt. % of TiO 2 , 65.3 wt. % of ethanol, 1.8 wt. % of ethyl cellulose, 23 wt. % of H 2 O and 4.5 wt. % of CH 3 COOH.