Comparative performances of nature-based dyes extracted from Baobab and Shea leaves photo-sensitizers for dye-sensitized solar cells (DSSCs)

Abstract

Dye-sensitized solar cells (DSSCs) were fabricated using dye extracts from Baobab and Shea leaves as photo-sensitizers. The photoanode was made from spin-coating of titanium dioxide (TiO2) and annealed at 450°C for 1 ​h. The TiO2 shows good optical absorption capability in the ultraviolet region with a band gap of 3.3 ​eV and surface morphology that revealed grains that are spherical and randomly oriented with average particle size of (26±4.0) nm. The Shea and Baobab dyes have shown absorption at the blue-yellow region of the visible light with energy band gap of 1.66 ​eV and 1.89 ​eV respectively. The Shea-based DSSC (SDSSC) yielded power conversion efficiency (PCE) of (0.25±0.13) % with short current density, Jsc, open-circuit voltage, Voc and fill factor, FF of (2.66±1.61)mAcm−2, (0.158±0.0877) V and 0.596 ​± ​0.389, respectively while Baobab-based DSSCs (BDSSCs) gave lower PCE of (0.11±0.028) % with Jsc, Voc and FF of (0.286±0.0483)mAcm−2,0.676±0.0622 V and 0.592±0.0339. Light soaking tests show that SDSSCs are more stable in photoelectric performance than BDSSCs for 5 ​h. Hence, preferred as a sensitizer for better performance in dye-sensitized solar cells than Baobab dye extract.

Keywords

• Baobab dye extract
• Shea dye extract
• Dye-sensitized solar cells
• Photo-sensitizers
• Optical properties
• Natural dyes