Phase behaviors of polymer blend(PEO-PPO) electrolyte/KI/I2 systems in dye-sensitized solar cells

초록

Photoelectrochemical solar cells based on Dye-ensitized TiO2 are considered to be promising alternatives to conventional silicon solar cells because of their low cost. Liquid DSSCs (Dye-Sensitized Solar Cells) and quasi-solid DSSCs have been studied by many groups up to now. However, Liquid DSSCs have had some draw backs like leakage and evaporation of electrolyte during long-term operation. On the other hand, solid state DSSCs have an advantage such as long-term stability. but they are known to result with insufficient performance, especially due to low ionic conductivity. Researches on the electrochemical applications of SPEs, Polymer Blends electrolytes have therefore focused on the ionic conductivity for each complex. Polymer blend (poly(ethylene oxide) (PEO)-poly(propylene oxide) (PPO)) systems with different mole ratios, complexed with KI/I2 redox couple, have been characterized at various temperatures and compositions using a thermo-optical analysis (TOA) technique. We also developed a new melting point depression theory based on the modified perturbed hard sphere chain model to interpret phase behavior of polymer blend electrolyte systems.