Fabrication and characterization of dye-sensitized solar cells based on hybrid photoanodes consisting of Zr-doped ZnO nanorods and TiO2 nanoparticles

Owing to its bandgap, surface structure, particle size, porosity, and film thickness, TiO2 is a popular photoelectrode in DSSCs. However, the electron mobility of TiO2 is too low to improve the photovoltaic performance of DSSCs further. As a result, much research on DSSCs has concentrated on improving electron transport with various semiconductor materials. Among all these semiconductor materials, ZnO has gotten the most interest because of its similar band gap to TiO2, greater electron mobility, easier tailoring, and easier surface modification than TiO2. As a result, it can be used as a working electrode in DSSCs with or without TiO2. One dimensional nanostructures have a lesser surface area for dye adsorption, and a hybrid film composed of ZnO nanorods (NRs) and TiO2 nanoparticles (NPs) is particularly effective in terms of surface area, light absorption, and charge transport. To further improve electron transport characteristics of ZnO NRs, in this study, they were doped with Zr (0.5, 1, 1.5, 2 and 2.5 wt.%). The current study used a hydrothermal technique to create DSSCs based on undoped and Zr-doped ZnO NRs/TiO2 NPs. XRD, SEM, EDS, and UV-Vis methods were used to characterize the samples. Furthermore, the photovoltaic performance of the devices used as the photoanode in DSSCs was measured. A power conversion efficiency of 3.31%, 4.91% and 8.33% was obtained for the devices assembled with conventional photoanodes of only TiO2 NPs, undoped ZnO NRs/TiO2 NPs and Zr-doped ZnO NRs/TiO2 NPs (at 2 wt.% of Zr), respectively. The results strongly suggest that Zr-doped ZnO NRs/TiO2 NPs-based photoanodes achieve a complementary effect in DSSC devices and consequently can be extended to similar applications.