The fabrication of ZnO solar cells double-sensitized by CdS@CdSe quantum dots through anion exchange method

CdS@CdSe QDs were introduced onto the interface of ZnO nanorods by SILAR and anionic replacement process. A wide light absorption spectrum was obtained in the CdS@CdSe QDs double-sensitized solar cells. The conversion efficiency of the ZnO solar cell is 1.06% (Voc = 0.58 V, Jsc = 5.90 mA/cm2, FF = 0.31). Band alignment was investigated by UPS pattern. The consequence implies that the energy level structure of CdS@CdSe QDs double-sensitized solar cell varied compared with a single-sensitized one. This new appearance of CdSe can not only work efficiently on broadening the absorption wavelength, but also promote the efficiency of charge injection. Ultimately, photovoltaic performance of the CdS@CdSe double-sensitized device was improved.