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Natural dye sensitizers were extracted from Terminalia catappa (R), Azadirachta indica (G), and Clitoria ternatea (B) using water as a solvent to sensitize the bare photo-anodes of N-DSSCs. The average crystalline size of a bare TiO2-based photo-anode was compared with a composite photo-anode which includes 1 wt% of MoO3. The anchoring capability of extracted sensitizers (R, G, and B) toward metal oxides was confirmed with a favorable functional group. Through UV–Vis–DRS Spectra, the light-harvesting capability to collect light was compared for each composite and a TiO2-based photo-anode that had been sensitized with respective sensitizer R, G, and B. The photo-catalytic performance of dye-anchored pure TiO2 and composite-based photo-anodes have been analyzed through recombination rate. Photovoltaic parameters of assembled N-DSSCs were calculated from the J–V graph. The overall efficiency of N-DSSCs incorporated with 1wt% MoO3 -based photo-anode sensitized with Terminalia catappa (as RB), Azadirachta indica (as GB), and Clitoria ternatea (as BB) shows diminished results than that of respective pure TiO2-incorporated photo-anode-based N-DSSCs. [ABSTRACT FROM AUTHOR]

Three different natural dyes, such as Terminalia kattapa (Red, fruit), Azadirachia indica (Green, leaf), and Clitoria ternatea (Blue, flower), were extracted to fabricate natural dye-sensitized solar cell (N-DSSC) with standard TiO2 nanoparticles (p25) on the FTO base layer. A comparative study was carried out on the performance of RA, GA, and BA-based DSSCs based on optical and electrical properties. The anatase and rutile phases on bare TiO2 film have been confirmed along with the formation of titanium sub-oxides due to the annealing process confirmed by X-ray diffraction. Significant absorption in the visible region has been attained in photo-anodes, which was confirmed with an optical band gap reported from UV reflectance spectra. For the proper electron injection process, a specific functional group has been identified in extracted sensitizer using Fourier transform infrared spectra to ensure the adsorption capability of dye molecules toward TiO2 particles. Photocatalytic properties of photo-anode have been analyzed using photoluminescence (PL) spectra by investigating the rate of recombination via PL intensity. J-V characteristics of fabricated N-DSSC with extracted natural dyes show that the N-DSSC with GA photo-anode offered the highest efficiency (0.79%) among other dyes used in this investigation, such as RA (0.51%) and BA-based photo-anode (0.29%). DSSCs fabricated using photo-anodes RA, GA, and BA (using water as solvent) show excellent outstanding stability and decent efficiency than the ethanol-based cells. [ABSTRACT FROM AUTHOR]