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2011
Conference Paper
Titel
Electrical and photoelectrical measurements on ZnO-Nanowires coated with PEDOT:PSS for dye-sensitized solar cells
Abstract
Dye-sensitized solar cells composed of an n-doped ZnO nanowire array and a p-doped polymer layer appears to be a promising candidate for low-cost production of environment-friendly solar cells. In this work, we investigate hybrid devices consisting of a transparent conducting oxide (TCO) substrate, ZnO-nanowires (ZnO-NW) or a sol-gel prepared ZnO layer, a ruthenium dye (N719) and a PEDOT:PSS or P3HT layer. The dense polycrystalline ZnO layer is able to prevent short circuits, which have a strong effect on the performance of the solar cells. This is demonstrated by the use of only the ZnO layer which improves the open circuit voltage by a factor of 2 and the efficiency by a factor of 1.7 compared to cells with nanowires. That indicates that the system combined with a thin but dense ZnO layer and NW grown on it will show further improvement. Furthermore three different TCO substrates were investigated. Impedance spectroscopy (IS) reveals at least one additional Schottky b arrier formed with ZnO:Al substrates. Spectral photovoltage measurements clearly show distinct absorption features correlated with the ZnO and N719 dye.