Enhanced photovoltaic performance of dye-sensitized solar cells-based Carica papaya leaf and black cherry fruit co-sensitizers

• Published in: Chemical physics impact 2021-06, Vol.2, p.100024, Article 100024
• Main Authors: Ossai, Amarachukwu N., Ezike, Sabastine C., Timtere, Pascal, Ahmed, Abubakar D.
• Format: Article
• Language: English
• Subjects: Black cherry fruit; Carica papaya leaf; Co-sensitizers; Dye-sensitized solar cells; Photovoltaic performance
• ISSN: 2667-0224; 2667-0224
• DOI: 10.1016/j.chphi.2021.100024

•Single and mixed dyes were extracted from Carica papaya leaf and black cherry fruit for use as photosensitizers.•The electron-injection barriers of the dyes with respect to the electrodes were obtained from cyclic voltammetry measurement.•The mixed dyes of black cherry fruit (B) and Carica papaya leaf (P) were obtained at different volume concentration ratios of B:P = 1:3, B:P = 1:1 and B:P = 3:1 for co-sensitization.•Optimized dye extract from b and p at B:P = 3:1 deployed in solar cell yielded power conversion efficiency (PCE) of 0.56% to compare single dye of p with PCE of 0.29%. Natural dye sensitizers are attractive as an alternative to expensive and rare organic sensitizers in dye-sensitized solar cells. The partial absorption of solar spectrum by solar cell-based natural dye negates its usefulness as the power conversion efficiency (PCE) is poor. Co-sensitization of two or more natural dyes with variant absorption spectra could be a feasible solution. Herein, Carica papaya leaf (P) and black cherry (B) fruit dye extracts were prepared and used as co-sensitizers at different volume concentration ratios (B:P=1:3, B:P=1:1 and B:P=3:1). The optical performance analysis shows that the light-harvesting ability of the device optimized after the co-sensitization at B:P=3:1 significantly improved. The DSSCs-based B and P show PCEs of 0.25% and 0.29%, respectively. The DSSC-based B:P=3:1 shows the highest PCE of 0.56%. Further investigation using cyclic voltammetry (CV) shows that DSSC-based B:P=3:1 has the smallest electron-injection barrier (ΔEe) among all the fabricated DSSCs while DSSC-based B has the highest ΔEe. Also, electrochemical impedance spectroscopy (EIS) reveals that the DSSC-based B:P=3:1 has the least charge flow resistance, thereby reducing charge recombination in the device. Meanwhile, the radius of the DSSCs-based B arc is the largest depicting presence of high charge flow resistance thereby increasing charge recombination in the device. The co-sensitizer, (B:P=3:1), compensates for absorption defects of single dye ((B or P) and improves the photo-response current. Also, it suppresses the charge recombination in the device and improves the PCE of the device. [Display omitted]