Preparation of nanocrystalline TiO2 with mixed template and its application for dye-sensitized solar cells

This work describes a procedure based on a mixed template of copolymer F127 [poly(ethylene oxide)(106)poly(propylene oxide)(70)-poly(ethylene oxide)(106)] and surfactant CTAB (cetyltrimethylammonium bromide) for generating anatase TiO2 nanocrystals. When the particle size is 3-5 nm, the surface area without aggregation is about 300 m(2)/g, but our experimental value is 180 m2/g. This means that not all surfaces of 3-5 nm particles are exposed. Then the prepared TiO2 narocrystals were used to assemble dye-sensitized very thin solar cells of about 6 mum. Its photocurrent-voltage performance was investigated. The mixed template allowed the fabrication of crack-free porous TiO2 film electrodes of various thicknesses by repetitive coating and calcinations. The transparent solar cell obtained with a six-time repetitive coating exhibited an open-circuit potential of V-oc = 760 mV; a short-circuit photocurrent density, J(sc) = 17.2 mA/cm(2); a fill factor, ff = 0.635; and an efficiency of eta = 8.3%. A solar cell using the commercial P25 as the TiO2 film electrode was also assembled for comparison, and the result are analyzed and discussed. (C) 2004 The Electrochemical Society.