CdS quantum dots sensitized single- and multi-layer porous ZnO nanosheets for quantum dots-sensitized solar cells

The photoelectrodes of quantum dots-sensitized solar cells (QDSCs) combining porous ZnO nanosheets and CdS quantum dots (QDs) were constructed and examined. The single- and multi-layer porous ZnO nanosheets were in situ grown on ITO conducting glass by electrodeposition at the deposition potentials of -0.5 and -0.8 V (vs. SCE), respectively, followed by a heat treatment. CdS QDs attached on porous ZnO nanosheets were synthesized by successive ionic layer adsorption and reaction method. The conversion efficiency achieved by the QDSC based on CdS QDs-sensitized multi-layer porous ZnO nanosheets (M-ZnO/CdS electrode) was 1.16% which was much higher than that based on CdS QDs-sensitized single-layer porous ZnO nanosheets (S-ZnO/CdS electrode). This was due to the more intense absorption of visible light by the M-ZnO/CdS electrode than that by the S-ZnO/CdS electrode. (C) 2011 Elsevier B.V. All rights reserved.