Quasi-solid-state Dye-sensitized Solar Cells Employing Fibers Stacked Paper Carbons as Efficient Counter Electrodes

Three types of paper carbons (PCs) were introduced into quasi-solid-state dye-sensitized solar cells (QDSCs) as counter electrodes. The PCs were respectively prepared using printed paper, filter paper and facial tissue as raw materials by one-step pyrolysis. Results show that each PC consists of carbon fibers with radial size of similar to 10 mu m, and has low crystallinity as well as well-developed porous structure. As a result, each type of PC displays more excellent catalytic activity for tri-iodide (I-3(-)) reduction than graphite, which brings about higher efficiency for use in QDSCs. In three PCs, PC fabricated from printed paper possesses the highest surface area and the most outstanding catalytic activity. This is mainly attributed to unique carbonaceous ramentums on carbon fibers in printed paper derived PC. Each type of PC in QDSCs not only provides catalytic active sites for I-3(-) reduction, but also serves distinctive function to improve the ion conductivity of quasi-solid-state electrolyte. Consequently, PCs based QDSCs have higher short-circuit current density (J(sc)) and open-circuit voltage (V-oc) compared with traditional Pt based QDSCs. The higher J(sc) and V-oc cover the insufficiency of fill factor, resulting in comparable efficiencies with traditional Pt based QDSCs.