Applied Surface Science, Vol.469, 821-828, 2019
Enhanced efficiency for dye-sensitized solar cells with ZrO2 as a barrier layer on TiO2 nanofibers
Due to its low cost and high efficiency, dye-sensitized solar cells have been widely studied. As all of known, nanoparticles are not conducive to the separation and transmission of electrons and holes. One-dimensional (1D) TiO2 nanofibers (NF), synthesized via electrospinning method, were used to replace the nanoparticles film. It offered a direct pathway and can absorb dyes to improve the efficiency, which had revealed distinct properties as a photoanode in DSSC. In addition, ZrO2, as a barrier layer on NF, enhanced the efficiency of dye sensitized solar cell. Moreover, the ZrO2 layer can availably enhance the efficiency by preventing recombination of electron-hole between TiO2 and the dye/electrolyte. Electrochemical Impedance Spectroscopy (EIS) measurements provided evidence that the coating ZrO2 reduced recombination losses at the photoanode-TiO2-dye vertical bar I-3(-)/I- electrolyte interface, which passivated localized surface states. Results of photovoltaic measurements of the NP/NF/ZrO2 DSSC revealed that a barrier layer of ZrO2 could improve efficiency. The NP/NF/ZrO2-based devices exhibited a higher efficiency of 6.72% than that of NP/NF (6.14%). This work provides a novel approach for the rational design of the photoanodes in DSSC, which also implies the potential application of this structure in other type of solar cells.