Observation of Positive Effects of Freestanding Scattering Film in Dye-Sensitized Solar Cells

Abstract

Dye-sensitized solar cells (DSSCs) with a nanocrystalline TiO(2) as a anode incorporating a free-standing and Flexible light-scattering film composed of sub-micrometer-sized Al(2)O(3) particles with a small amount of ion-transportable polymeric binder were prepared and compared to DSSCs composed of a nanocrystalline TiO(2)/sub-micrometer-sized TiO2 bilayer as an anode. The cell efficiency of the former was higher than that of the latter. This implies that the enhancement of the light absorption as that obtained with a general DSSC with light-scattering layer (sub-micrometer-sized TiO(2)) is possible by combining a high-surface-area layer of nanocrystalline TiO(2) and free-standing light scattering him. The novel DSSCs with the free-standing light scattering him showed an additional resistance, which was characterized by the electrochemical impedance analysis. However, the cell performance was not seriously influenced by the additional resistance. When the free-standing scattering film was assembled with Flexible type DSSCs, not only a greatly enhanced power conversion efficiency but also better long-term stability than the DSSC without the light scattering film were observed.