Harnessing Nature’s Colours: Experimental and Computational Insights into Bixa orellana Pigments for Next-Generation Dye-Sensitized Solar Cells

The potential of Bixa orellana (annatto) pigments, specifically bixin and norbixin, as sensitizers for dye-sensitized solar cells (DSSCs) was investigated. The pigments were extracted using various solvents (acetone, methanol, ethanol, and hexane), and their optical and photo-electrical properties were investigated using UV-Vis spectroscopy and photoelectrical analysis. Results indicate that acetone extract (a-AP) exhibited the highest power conversion efficiency (PCE) of 0.786%, attributed to its broad absorption spectrum and optimal electronic properties. Quantum chemical calculations revealed that both bixin and norbixin exhibit favourable frontier orbital energies and energy gaps, making them well-suited for efficient electron injection and light absorption. These findings position Bixa orellana pigments as promising, eco-friendly alternatives to conventional synthetic sensitizers, offering a pathway toward more sustainable, locally adaptable, and efficient solar energy harvesting.