Plastic dye-sensitized photo-supercapacitor using electrophoretic deposition and compression methods

A plastic photo-rechargeable capacitor is studied using a three-electrode configuration, separating a flexible dye-sensitized solar cell (DSSC) and a supercapacitor by sharing a common Pt electrode. The thick and uniform TiO₂ film is formed by using commercially available TiO₂ nanocrystals, which are treated in an isopropyl alcohol without surfactant by the electrophoretic deposition (EPD) to deposit the mesoporous TiO₂ photoanode film with good adherence onto the plastic substrate. Afterward, a static mechanical compression technique as the post-treatment is employed to the electrophoretic deposited film in order to enhance the particles connection. In addition, a supercapacitor using PEDOT (poly(3,4-ethylenedioxythiophene)), which is potentiostatically electropolymerized to form a thick film, is fabricated to store the energy. The flexible DSSC part is fabricated with a TiO₂ film of 10.9 μm thickness and it can provide photoelectric conversion efficiency up to 4.37% under 1 sun illumination. The photocapacitor is made with such a flexible DSSC and a supercapacitor with ca. 0.5 mm thick PEDOT film, which provides a specific capacitance of 0.52 F cm⁻².