Impedance analysis of charge transfer upon nickel doping in Tio 2 -based flexible dye-sensitized solar cell

Flexible dye-sensitized solar cells (FDSSCs) have promoted interest in plastic industries as they are lightweight, flexible, and mechanically robust to accelerate production and reduce cost. However, the plastic substrates have temperature limitations in producing the TiO2 photoanode and degrade the performance of FDSSC. The main reason for this degradation is the low charge transfer in the photoanode layer. Although there is plenty of research on low-temperature fabrication methods, they indirectly increase the operational cost. Therefore, a new approach is necessary for charge transfer improvement without affecting the temperature in a low-cost platform. In this study, we present a photoanode that improves the charge transfer by doping nickel (Ni) in the TiO2 layer. A low amount of Ni doping (15%) exhibited Rct >> Rt, indicating a high charge transport and low electron recombination rate (120.84 s−1). On the other hand, higher amount Ni doping (>> 45%) has Rct << Rt which deteriorates the performance of the cell by causing severe agglomeration issues, indicating a high electron recombination rate (369.75 s−1). Moreover, the high charge transfer in (TiO2)85-Ni15-based FDSSC facilitates the electron lifetime of the cell up to 8.28 ms. Therefore, an optimum doping of Ni in TiO2-based FDSSC is studied in this work.