A quasi solid-state dye-sensitized solar cell containing binary ionic liquid and polyaniline-loaded carbon black

摘要

A quasi solid-state dye-sensitized solar cell (DSSC) is fabricated using 1-propyl-3-methylimidazolium iodide (PMI1) and polyaniline-loaded carbon black (PACB) as the composite electrolyte. The electrolyte without added iodine is sandwiched between TiO_2 working electrode and platinum counter electrode (CE). A power conversion efficiency (η) of 5.81% is achieved with this type of cell. With the addition of l-ethyl-3-methylimidazolium thiocyanate (EMISCN), a low-viscosity ionic liquid (IL), the cell with the binary ionic liquid (bi-IL) renders an efficiency of 6.15%, the best for any quasi solid-state DSSC without the addition of iodine. To fabricate a low cost DSSC using the bi-IL, the platinum layer of the counter electrode is replaced with a polymer layer, 3,3-diethyl-3,4-dihydro-2H-thieno-[3,4-b][1,4] dioxepine (PProdot-Et_2) through electrodeposition, and the corresponding DSSC shows an efficiency of 5.27%. At-rest stability of the quasi solid-state DSSC with bi-IL is compared with that of a liquid electrolyte DSSC at room temperature; the power conversion efficiency of the former shows a decrease of hardly 3% after 1000 h, while that of the latter shows a decrease of about 30%. The quasi solid-state cell shows unfailing durability at 70℃.