Investigation on the properties of La-doped and Dy-doped ZnO nanorods and their enhanced photovoltaic performance of Dye-Sensitized Solar Cells

Pure ZnO nanorods with various times, La-doped ZnO NRs and Dy-doped ZnO NRs were synthesized through two steps: seed layer by spin coating method and growing of nanorods by hydrothermal method. X-ray diffraction, field emission scanning electron microscopy, dispersive X-ray spectroscopy, photoluminescence spectroscopy and ultraviolet-visible spectrometer were used to investigate the structure composition and the optical properties of the products. The optical measurements indicated an enhancement in absorption and emission intensity, when the length of nanorods and impurities concentration were increased and furthermore, the band gap of ZnO nanorods was decreased. Dye-Sensitized Solar Cells were fabricated using ZnO nanorods grown on the porous TiO2 nanoparticles film (TiO2 NPs/ZnO NRs) as the photoanodes. The effect of different growth time and various dopants were investigated on the performance of DSSCs. The optimum performance of DSSC was achieved by ZnO NRs grown for 300 min. The performance of DSSC based TiO2 NPs/ZnO NRs decorated with TiO2 NPs was obtained 5.99% and cell efficiency was improved more than twice compared with the undecorated photoanode. The power conversion efficiency of DSSCs doped with Lanthanum and Dysprosium was also increased by 63.6% and 71.5%, respectively, in comparison with the conventional TiO2 NPs photoanode.