Photovoltaic Performance of New-Structure ZnO-nanorod Dye-Sensitized Solar Cells

Abstract

Currently, the photoelectrode of nanorod-based dye-sensitized solar cells (DSSCs) consists of nanorods grown on a transparent conducting layer (TCO) substrate. This work presents a new structure for nanorod DSSCs. ZnO nanorods and a ZnO film were cogrown using a one-step chemical-vapor deposition method. The ZnO film functioned as the TCO of the DSSC. The ZnO nanorod/ZnO film structure was sensitized with D149 or N719 dye and assembled into a DSSC. Two notable features in this new DSSC structure are: (1) the junction between the TCO film and the nanorods is completely eliminated; (2) the TCO and the photoelectrode are made of the same material. Testing showed that under AM1.5 illumination, a short current density of 15.7 mA/cm(2) and a power conversion efficiency eta of 1.82% can be achieved. The eta is more than two times higher than the eta reported earlier for ZnO-nanorod DSSCs with the same structure.