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.