Abstract
This study investigates the electrochemical properties of electrolyte-impregnated micro-porous ceramic (Al2O3) films as framework supports in dye-sensitized solar cells (DSSCs). A field-emission scanning electron microscope (FE-SEM) is used to characterize the morphology on both surfaces of the ceramic membranes, which exhibit high porosity (41-66%) and an open cylindrical pore structure. Electrochemical impedance analysis reveals that the conductivity of the electrolyte-impregnated ceramic membrane is lower (6.24-9.39 mS cm-1) than the conductivity of the liquid electrolyte (25 mS cm-1), with an Archie's relationship by a power of 1.81 to the porosity value. The diffusivity of tri-iodide ions (I3-) is slowed from 1.95 × 10-5 to 0.68 × 10-5 cm2 s -1 in the ceramic-containing cells. The exchange current density at the Pt-electrolyte interface decreases slightly (less than 5%) when the Al 2O3 membranes were used in the symmetric cells, implies that the contact of the denser ceramic top structure on the Pt electrode does not interfere with the I3- charge transfer. The ceramic films can prevent solvent evaporation and maintain conductivity. The long-term cell efficiencies are evaluated up to 1248 h under alternating light soaking and darkness (3 days/4 days) cycles. The cells containing the ceramic films outperform the control cells.
Original language | English |
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Pages (from-to) | 4162-4172 |
Number of pages | 11 |
Journal | Journal of Power Sources |
Volume | 196 |
Issue number | 8 |
DOIs | |
State | Published - 15 04 2011 |
Keywords
- Cell performance
- Electrolyte-filled micro-porous framework
- Limiting current density
- Porosity
- Tri-iodide diffusion coefficient