The effect of the number of calcination steps on preparing crack free titania thick templated films for use in dye sensitized solar cells

Crack free titania thick templated films were prepared by evaporation-induced self-assembly (EISA) process and spin coating method with different numbers of calcination steps; then, their application in dye sensitized solar cells (DSSC) was investigated. Wormlike meso-layers prepared at different spin speeds were characterized by TEM analysis. The correlation between spin speed and thickness and porosity of the films were investigated using ellipsometry method. The crystallinity and surface area of the films obtained at a repeated thermal treatment method and different temperatures were investigated by XRD and BET techniques. UV-vis spectroscopy and cross-sectional SEM images were also used to characterize the films. Finally, the mesoporous thick films (5.7 µm) were used in DSSC devices and their photovoltaic performances were examined. The optimum mesoporous film exhibited an open-circuit voltage (VOC) of 0.729 V, short-circuit current density (JSC) of 14.93 mA cm−2, fill factor of 0.68 and a power conversion efficiency of 7.35%.