Bismuth Borosilicate-Based Thick Film Passivation of Ag Grid for Large-Area Dye-Sensitized Solar Cells

Abstract

A bismuth borosilicate glass-based thick film having a low glass transition temperature of 445 degrees C was investigated as a passivation layer for protecting Ag-grid against corrosive reactions with the common I-/I(3)- electrolyte for large area dye-sensitized solar cells (DSSC). Glass paste was carefully screen-printed and then fired in the temperature range of 480 degrees-540 degrees C to have a final thickness of similar to 4 mu m. The effectiveness of the glass passivation film was related to the degree of densification or porosity, which depended on firing temperature of the glass. A high optical transmittance of similar to 70% and the chemical inertness of the well-densified glass film can be highlighted as promising characteristics for this passivation application. The low electrical resistance of similar to 27 of the fluorine-doped tin oxide-coated substrate, which was obtained by patterning Ag grid, remained stable over the exposure period of similar to 10 days in the electrolyte only when the hermetic protection of Ag was secured by the glass overcoat film after densification at 540 degrees C.