Quantum Dot-Sensitized Solar Cells - Low-cost Nanomaterials: Toward Greener and More Efficient Energy Applications - page 110

Fig. 15 a and c SEM images of pure and QDs-sensitized Si/ZnO hierarchical structure,
respectively; b and d, corresponding TEM images; e diffused reflectance spectra and f IPCE
spectra of Si/ZnO hierarchical anode based QDSCs; g J-V performance of conventional ZnO
nanowire array and Si/ZnO hierarchical anode-based QDSCs compared with corresponding
schematic anode structure (Sudhagar et al. [ 70 ] Reprint permission from ACS Publishers)
the Si backbone nanowire played an important role in the performance: the ZnO NR
had a J sc of 8.0 mA/cm 2 and efficiency of 2.7 %, whereas the 3-D pine tree QDSC
resulted in J sc of 11.00 mA/cm 2 and efficiency of 3.00 % (Fig. 15 g). It is indicated,
pine tree structures have the additional advantage of the fast electron transport
through n-Si NWs. More importantly, we demonstrated that it is possible to obtain
higher V oc QDSCs with an appropriate treatment of the recombination process,
highlighting the fact that QDSCs have to be rethought, separately of DSCs, to
optimize their performance.