Low temperature preparation of TiO2 films by cold isostatic pressing for flexible dye-sensitized solar cells

The flexible TiO2 photoelectrodes were fabricated by coating P25 (TiO2 nanoparticles; Degussa, Germany, a mixture of ca. 30% rutile and 70% anatase) paste on ITO-PEN substrates using doctor-blade method. The photoelectrodes were treated by cold isostatic pressing method under different pressure. The interconnection of nanoparticles and mechanical adhesion between the films and the substrates were improved under high pressure. The photovoltaic performances of the flexible dye-sensitized solar cells (DSSCs) were remarkably correlative to pressure. The DSSCs employing the flexible 300MPa-pressed TiO2 photoelectrodes achieved conversion efficiency as high as 2.06% under AM 1.5 simulated sunlight. By replacing the solvents of the paste, the efficiency of the cell was improved to 2.87%. ► The flexible TiO2 photoelectrodes were treated by cold isostatic pressing method. ► The interconnection of nanoparticles and mechanical adhesion between the films and the substrates were improved under high pressure. ► The solar cell achieved conversion efficiency as high as 2.87%.