Preparation of dye sensitized solar cell by using supercritical carbon dioxide drying

Dye-sensitized solar cells (DSSC) derived from TiO₂ aerogel film electrodes were fabricated. TiO₂ aerogels were obtained by using sol–gel method and supercritical carbon dioxide (sc-CO₂) drying. First, TiO₂ wet gels were obtained by sol-gel method. Then, the solvents in the TiO₂ wet gels were replaced by acetone. The TiO₂ aerogels were obtained by using sc-CO₂ drying from the TiO₂ wet gels. The conditions of sc-CO₂ drying were at 313, 323 K and 7.8–15.5 MPa. The electrodes with TiO₂ aerogel films were obtained by deposition of the aerogels on glass substrates. The electrodes with TiO₂ aerogel films and a commercial particle film of various thickness were obtained by repetitive coatings and calcinations. The amount of dye adsorbed on the TiO₂ films with sc-CO₂ drying was higher than that of commercial particle film. The amount of dye adsorbed on the TiO₂ films increased with increasing surface area of the TiO₂ film. DSSCs were assembled by using the TiO₂ aerogel film electrodes and their current–voltage performance was measured. The power performance of DSSC made by supercritical drying was higher than that of commercial particles. The DSSC with the film electrode made at 313 K and 15.5 MPa showed the best power performance (J_sc = 7.30 mA/cm², V_oc = 772 mV, η = 3.28%).