Natural Anthocyanin-Sensitized DSSCs with Optimized TiO₂/Nb₂O₅ Photoanode Architecture

In this study, a functional experimental model of dye-sensitized solar cells (DSSCs) based on natural anthocyanin dyes was developed, optimized, and evaluated under under simulated solar irradiation using a solar simulator. The photoanode architecture was optimized using a nanostructured TiO₂ film deposited on ST-FTO substrates, followed by controlled thermal treatment to improve adhesion, porosity, and electron transport. The influence of the number of TiO₂ layers on photovoltaic performance was investigated by comparing configurations with one, two, and three layers. In addition, a thin Nb₂O₅ interfacial layer was introduced to reduce electron recombination and improve charge transfer at the TiO₂/conductive substrate interface, while also acting as a light-scattering layer. Natural anthocyanin dyes extracted from various plant sources were used as photosensitizers. The assembled DSSC devices were tested using a solar simulator. The results demonstrated that the photovoltaic performance strongly depends on the photoanode architecture and the type of dye used. Increasing the number of TiO₂ layers enhanced the generated power due to improved dye adsorption and larger active surface area, while the introduction of the Nb₂O₅ layer significantly reduced recombination processes and improved charge transport.

The optimized DSSC configuration, consisting of three TiO₂ layers, an intermediate Nb₂O₅ layer, anthocyanin dye extracted from blackberries, an iodide/triiodide electrolyte, and a graphite counter electrode, demonstrated a stable and reproducible photovoltaic response. These results confirm the potential of natural anthocyanin dyes as sustainable sensitizers for environmentally friendly DSSC devices.