A suitable chemical conversion route to synthesize ZnO/CdS core/shell heterostructures for photovoltaic applications

In order to improve the performance of ZnO-based solar cells, ZnO/CdS core/shell heterostructures were synthesized via a facile chemical conversion route. Large area and quasi-aligned ZnO nanowire arrays were firstly fabricated on conductive glass substrates, and then the synthesis of ZnO/ZnS and ZnO/CdS heterostructures were realized by a chemical conversion method. The morphology and structure of the obtained products has been confirmed by field-emission scanning electron microscopy and X-ray diffraction measurements. The synthesized ZnO/CdS core/shell heterostructures were successfully applied in solar cells. The photovoltaic performance investigation demonstrates that the synthesized ZnO/CdS heterostructure-based solar cell shows a higher short-circuit current density compared with the N719 dye-sensitized ZnO nanowire array counterpart. The enhancement in current density may be due to the fact that the surface coverage of the light absorption layer in the ZnO/CdS core/shell heterostructure is very high. These results indicate that the synthesized ZnO/CdS heterostructures by the present method are very suitable for the application as photoelectrode in solar cells.