Hydrothermal growth and application of ZnO nanowire films with ZnO and TiO 2 buffer layers in dye-sensitized solar cells

Abstract

This paper reports the effects of the seed layers prepared by spin-coating and dip-coating methods on the morphology and density of ZnO nanowire arrays, thus on the performance of ZnO nanowire-based dye-sensitized solar cells (DSSCs). The nanowire films with the thick ZnO buffer layer (~0.8-1 μm thick) can improve the open circuit voltage of the DSSCs through suppressing carrier recombination, however, and cause the decrease of dye loading absorbed on ZnO nanowires. In order to further investigate the effect of TiO 2 buffer layer on the performance of ZnO nanowire-based DSSCs, compared with the ZnO nanowire-based DSSCs without a compact TiO 2 buffer layer, the photovoltaic conversion efficiency and open circuit voltage of the ZnO DSSCs with the compact TiO 2 layer (~50 nm thick) were improved by 3.9-12.5 and 2.4-41.7%, respectively. This can be attributed to the introduction of the compact TiO 2 layer prepared by sputtering method, which effectively suppressed carrier recombination occurring across both the film-electrolyte interface and the substrate-electrolyte interface. © To the authors 2009.