Investigation of Aloe Vera Latex Used as Natural Dye in TiO₂-Based Heterojunction and Liquid-Electrolyte Dye-Sensitized Solar Cells

The use of naturally extracted compounds as dye sensitizers is a very promising alternative for the manufacture of low-cost solar cells. These directly convert solar energy to electricity. In the present study, aloe latex solid (ALS), which is an orange-yellow solid compound extracted from aloe vera leaves, was deposited on a TiO₂ thin film (TiO₂/ALS) for the construction of two different solar cell configurations. The UHPLC-DAD-ESI-MS analysis, UV–Vis, and FTIR spectroscopic studies were performed for the prepared dye sensitizer. In fact, the performance of the TiO₂/ALS composite was investigated in a heterojunction dye-sensitized solar cell (HJ-DSSC) and a liquid-electrolyte-based dye-sensitized solar cell (LE-DSSC) to identify the architecture with the highest efficiency of sunlight conversion. The solar cells’ photovoltaic performance in terms of short-circuit current, open-circuit voltage, fill factor, and energy conversion efficiency was tested with photocurrent density–voltage measurements. Interesting solar conversion efficiencies were obtained for both architectures with a maximum value of about 1.17% corresponding to the LE-DSSC configuration.