CDS Quantum Dots Induced Surface Modification of ZnO Nanorods for Dye Sensitized Solar Cells
Abstract:
In this study, zinc oxide nanorods (ZnO NRs) were fabricated utilizing a straightforward sol-gel process at ambient temperature. A novel approach was reported to enhance the photovoltaic performance of dye-sensitized solar cells (DSSCs) by surface modifying ZnO NRs with CdS quantum dots (QDs). The CdS QDs-induced surface modification leads to improved light absorption, charge separation, and transfer efficiency. The ZnO-CdS nanostructures were characterized using XRD, TEM, and UV-Vis spectroscopy, revealing uniform decoration of CdS QDs on ZnO nanorods. An optical investigation showed that the sensitization of CdS QDs on to ZnO NRs led to a red-shift in the material. At the same time, the absorbed N719 dye molecule further boosts the visible light, which can significantly increase the overall efficiency of a solar device. The modified ZnO-CdS photoanode exhibited a significant enhancement in power conversion efficiency (PCE) of 26.57 % compared to bare ZnO nanorods. The improved performance is attributed to the enhanced electron injection and reduced recombination rate. The ZnO - N719 dye showed an efficiency of power conversion of 1.79 %, while the ZnO -CdS QDs showed an efficiency of 0.57 %. In addition to this, the ZnO: CdS: N719 co-sensitized device had a conversion efficiency of 2.07 %. This study demonstrates a promising strategy for designing high-efficiency DSSCs using semiconductor nanostructures.
