Bridelia ferruginea dye-synthesized zinc oxide nanoparticles and its nitrogen and sulphur doped as a photoanode in photovoltaic cell fabrication

The current global challenges re-emphasized the need to deviate from the use of fossil fuels. Photovoltaics cells with proper and adequate manufacturing processes have consistently shown excellent characteristics capable replacements for the fossil fuels. ZnO nanoparticle was synthesized using Bridelia ferruginea dye and subsequently doped with Nitrogen (N) and Sulphur (S), via thermal annealing. The phytochemical analysis of dyes shows a high presence of the phenolic group, while the quantitative (antioxidant parameters) analysis to identify capping and stabilizing agents confirmed the presence of phenol (9.83 mg g −1 ), flavonoid (171.01 mg g −1 ), FRAP (0.412 mM g −1 ), DPPH (12.63) and Fe chelation ability (7.12%). Trans-Octadec-9-enoic acid, n-hexadecanoic acid and Phytol which are the major compounds in the dye were identified with the aid of GC/MS spectroscopy. The synthesized ZnO and ZnO-N,S were characterized using UV–vis spectroscopy and shows characteristic absorption between 300 and 400 nm. Fourier transform infrared identifies some of the functional groups (N–O, C=O and OH) that actively reduced the bulk material to their nanoform. X-ray diffraction confirmed crystallinity for ZnO nanoparticles and a mixture of amorphous and crystallinity when the nanoparticles were doped with N and S with corresponding grain sizes of 19.02 and 18.98 nm, respectively. BET plot reveals surface areas of 30 and 15 m 2 g −1 for ZnO and ZnO-N,S, respectively. Scanning electron microscopy –energy-dispersive X-ray spectroscopy and transmission electron microscopy confirmed the morphology and the elemental composition of the synthesized nanomaterials. Photoelectrochemical analysis affirmed the alternation of synthesized material from an n-type to a p-type conductivity as the temperature varies. The photovoltaic properties of the fabricated dye-sensitized solar cells (DSSCs) were evaluated using electrochemical impedance spectra, this has proven DSSCs assembled with the ZnO-N,S photoanode to have a better solar to electrical energy conversion (0.67%) when compared with DSSCs with ZnO photoanodes. The relatively high conversion efficiency of ZnO-N,S reveals its suitability for use in high-performance DSSCs. Moreover scaling up the material for public utilization could assist considerably to solve the perennial power crises in developing countries as well as curtain the use of fossil fuel, which is identified as a major source of pollutants to the environment.