Carbon Black and Titanium Interlayers Between Zinc Oxide Photo Electrode and Fluorine-Doped Tin Oxide for Dye-Sensitized Solar Cells.

Carbon black and titanium interlayers were deposited on fluorine-doped tin oxide (FTO) anode layers using radio frequency magnetron sputtering method. On top of them, Zinc oxide (ZnO) photo anode layers were prepared using plasma enhanced chemical vapor deposition technique. ZnO high binding energy as well as good breakdown strength, cohesion, and stability used as a photo electrode material for dye-sensitized solar cells (DSSC), but it does not have a good electrical contact to the FTO anode. To solve this problem, the carbon black and titanium interlayers were deposited. The effect of interlayers on the power conversion efficiency (PCE) of DSSCs was investigated. The PCE of the devices with 120-nm-thick interlayers of carbon black or titanium was 5.21 or 4.45%, respectively, which were larger than the PCE of the devices without such interlayers (3.25%). The smooth interface of the carbon black interlayer reduced the interface impedance of the ZnO photo anode effectively. On the other hand, the titanium interlayer with TiO₂ on the ZnO side increased the impedance, and decreased the PCE.