Modification of solvolytic sol-gel synthesis for low temperature TiO₂ DSSC photoelectrode

Solvolytic sol-gel synthesis was applied for the low temperature production of photoelectrode for dye-sensitized solar cell (DSSC). In this study, commercial TiO₂ standard (Degussa P25) was used as the main component in the preparation of photoelectrode film. Addition of TiO₂ gel prepared from a solvolytic sol-gel method reduced cracking in the dry film while still maintains porosity. Further modification by simply adding hydrofluoric acid (HF) and ammonia (NH₃) increase porosity and improve interconnection between fluorine doped tin oxide (FTO) layer on the substrate and the coated TiO₂ layer even under low temperature baking condition (<150°C). The modified TiO₂ electrode showed significantly better electrical and electrochemical properties. Furthermore, the DSSC cell with modified TiO₂ film also showed higher cell efficiency when compared with the controlled cell that used only Degussa P25.