Effect of nickel oxide concentration on titanium oxide bilayer photoanode for dye-sensitized solar cell application

The mesoporous titanium oxide has attracted significant attention as a photoanode material for Dye-Sensitized Solar Cells (DSSCs). In the present work, we coated a planar NiO layer on the TiO₂ film to minimize charge recombination with the dye and/or electrolyte molecules. The structural, morphological, elemental, optical, and electrical properties of the TiO₂ and bi-layered TiO₂/NiO films were studied using various characterization techniques. DSSCs based on N3 dye-sensitized TiO₂ and bi-layered TiO₂/NiO films were fabricated using PI as the redox electrolyte. The photocurrent density–voltage (J–V) characteristics of the DSSCs were studied using a solar simulator. Various parameters, such as open-circuit voltage (V_oc), short-circuit photocurrent density (J_sc), and fill factor (FF), were calculated from the J–V characteristics. DSSCs based on bi-layered TiO₂/NiO films showed superior performance compared to bare TiO₂ films. The J–V characteristics of bilayer film shows enhanced open-circuit voltage (Voc) ~ 0.56 V, short-circuit current density (Jsc) ~ 2.14 mA/cm², fill factor (FF) ~ 75%, and efficiency (ƞ) ~ 0.91%. The TiO₂/NiO solar cell showed a ~ 28% increase in efficiency compared to TiO₂-based DSSC. Hence, the bi-layered TiO₂/NiO films have potential applications in optoelectronic and photovoltaic devices.