Investigation of Dye-Sensitized Solar Cell With Photoanode Modified by TiO₂-ZnO Nanofibers

In this study, the zinc oxide (ZnO)-titanium dioxide (TiO₂) composite nanofiber (NF) is prepared and used as an additional layer between TiO₂ layer and electrolyte on the photoanode of dye-sensitized solar cells (DSSC) to improve the power conversion efficiency ( ${\eta }$ ). The various weight ratios of ZnO/TiO₂ in ZnO-TiO₂ NF are manufactured by electrospinning technique. The photovoltaic parameters of DSSC are measured with the solar simulator under air mass 1.5 global (100 mWcm⁻²). The results show that the highest power conversion efficiency of the photoanode modified with ZnO-TiO₂ nanofiber at the weight ratio of ZnO/TiO₂ = 3/97 is 6.33%, which is 16% higher than that of the photoanode without modification. The other photovoltaic parameters such as $\text{J}_{\mathrm{ sc}}$ , $\text{V}_{\mathrm{ oc}}$ , and FF are 12.03 mA cm⁻², 0.79 V, and 0.66, respectively. The incorporation of ZnO allows the electrons to rapidly transfer and inhibit the electron recombination, and also successfully improves power conversion efficiency. The change in impedance between the photoanode and the electrolyte is measured by electrochemical impedance spectroscopy. Improvements in DSSC impedance are related to the decrease of charge recombination.