TiO2 nanocrystalline microspheres as an effective scattering layer in bilayer photoanodes for DSSCs

Among emerging solar technologies, Dye-sensitized solar cells (DSSCs) stand out for their scientific and technological attention for indoor and outdoor light harvesting applications. However, their efficiency is often hindered by limited light harvesting and recombination losses of electrons. To address these challenges, TiO 2 microspheres synthesized by the hydrothermal technique were utilized as a light scattering layer (LSL) in bilayer photoanode configuration. We report on the characterization of TiO 2 along with its utilization in an LSL using the microsphere structure. TiO 2 (P25), which ensures improved dye uptake and efficient electron transport, while the microsphere-based scattering layer redirects unabsorbed photons back into the photoanode. This design significantly improves light-harvesting efficiency using ruthenium-based sensitizing dyes like N3, N719, 520 DN, and Black, resulting in elevated J sc and overall power conversion efficiency (η) compared to conventional single-layer electrodes. Which is in good agreement with the Incident Photon to Current Conversion Efficiency (IPCE) spectra data. The highest J sc of 4.308 mA/cm 2 , 1.59% efficiency, and 43.53 ms mean electron lifetime was achieved for the bilayer photoanodes with N3 dye. These results demonstrate the potential of TiO 2 microspheres to enhance light harvesting in DSSCs and may be explored for future T-DSSC applications.