All-plastic dye-sensitized solar cells (DSSCs) using TiO2 paste (SP-210), indium tin oxide-coated polyethylene naphthalate (PEN/ITO) film and a Pt-coated PEN/ITO film counter electrode, were fabricated with 1.0 wt% kappa-carrageenan solid electrolyte containing the redox electrolytes (I-/I-3(-)) solution. The cell performance of the all-plastic cell using 1.0 wt% kappa-carrageenan solid electrolyte was investigated in comparison with liquid type one, showing that the values of V-oc (open circuit voltage) and ff (fill factor) were the same, but J(sc) (short circuit current) and eta (conversion efficiency) were slightly larger for the liquid type electrolyte cell than the solid type one. A higher conversion efficiency was exhibited by UN-irradiation. before heat treatment of the PEN/ITO/TiO2(SP-210) film than that after heat treatment. The effect of heat treatment conditions was investigated according to a modified hydrothermal treatment of the PEN/ITO/TiO2(SP-210) film, showing that the ff values become high (> 0.7) by hydrothermal treatment. The electrochemical impedance spectroscopy (EIS) has shown the important comparison of each charge transport processes between the all-plastic and the conventional cells. (c) 2006 Elsevier B.V. All rights reserved.