Ameliorating the photovoltaic conversion efficiency of ZnO nanorod based dye-sensitized solar cells by strontium doping

摘要

Strontium doped ZnO nanorods with various concentrations were grown by a simple and low-cost reflux method. The structure and morphology of the prepared samples were studied by X-ray diffraction and scanning electron microscopy. The results demonstrate the hexagonal wurtzite structure and the presence of strontium atoms in the ZnO lattice. Transmission emission mi-croscopy, diffuse reflectance, and photoluminescence studies were also performed to characterize the prepared samples. The optical measurements revealed the shrinkage in the band gap from 3.24 to 3.18 on 3:97 M Sr:ZnO doping. Dye-sensitized solar cells (DSSCs) were fabricated by using the undoped and Sr~(2+) doped ZnO based photoanodes. Electrochemical impedance spectroscopic studies revealed the charge transfer properties of the prepared DSSCs. An increased short-circuit current density of 1.93 mAcm~(-2) and photovoltaic conversion efficiency of 1.02% were obtained with 3:97 M Sr: ZnO based DSSC, while undoped ZnO based DSSC exhibited a current density of 1.37 mAcm~(-2) and efficiency of 0.80%. The morphological changes and the improved light scattering ability of the doped ZnO have resulted in the enhanced photovoltaic performance.