Opto-Electrical characterization of Bio-Dye extract from Baobab and Neem Tree Leaves for Dye Sensitized Solar Cell Application

Abstract

Solar power research mainly centers on developing cost-effective, eco-friendly solar cells. Perovskite, Quantum Dot (Q.D), and Dye Sensitized Solar Cells (DSSCs) are prominent subjects. DSSCs with ruthenium-complex dyes exhibit high efficiency, but ruthenium's scarcity, cost, and toxicity drive exploration of natural dye substitutes. This study examines blending multiple natural dyes to alter the optical band gap and subsequently enhance DSSC efficiency. The change in Eg in response to blending at 33%, 50% and 67% by volume of baobab to neem extract has been determined and explored using UV-Vis spectroscopy and Tauc’s approximation method. The individual band gap energies for pure baobab and pure neem extracts were identified as ca.1.65eV and ca.1.76eV, respectively. The Bandgap Energy for the blends obtained were 1.718 eV for 1:1, 1.778eV for 1:2, and 1.693 eV for 2:1 blend. This observed shift in band gap energy signifies an enhancement in the optical characteristics of the resultant dyes. Consequently, the blended extracts exhibit superior optical absorption properties compared to their parent dyes, positioning them as more effective sensitizers for dye-sensitized solar cells. The DSSCs sensitized with 33% Baobab 67% Neem ratio showed a significant enhancement in short-circuit current density (JSC) and open-circuit voltage (VOC). This blending approach also led to a substantial increase in power conversion efficiency (ƞ) for Baobab DSSCs. The findings underscore the potential of these blended bio-dye extracts in advancing the efficiency of solar cell technologies.