Biogenic synthesis of Zinc oxide nanoparticles for solar cell application and photodegradation of neomycin

Abstract

The biogenic synthesis of zinc oxide nanoparticles (ZnO NPs) using Syzygium malaccense leaf extract offers an eco-friendly approach to nanomaterial fabrication. This study employed Syzygium malaccense leaf extract as a reducing and stabilizing agent for synthesizing ZnO NPs. The ZnO NP was characterized by UV–Vis spectroscopy, FTIR, XRD, and SEM-EDX. UV–Vis spectroscopy revealed a strong absorption peak at 371 nm, corresponding to a bandgap energy of 3.23 eV, determined by Tauc’s plot. FTIR identified characteristic Zn–O, C-O, and C=C bonds at 574 cm⁻¹, 1188 cm⁻¹, and 1643 cm⁻¹, respectively. XRD analysis demonstrated the crystalline nature of ZnO with an average crystallite size of 25 nm and face-centred cubic (FCC) crystal structure. SEM-EDX provided insights into the surface morphology and elemental composition. The photocatalytic efficiency of ZnO NPs was evaluated on Neomycin (NEO) under UV light. The degradation reaction process followed a pseudo-first-order kinetic model with a reaction rate constant (k) value of 0.021 min⁻¹ and R² value of 0.87 (87 %). Additionally, ZnO NPs were incorporated into dye-sensitized solar cells (DSSCs) as a functional layer. Maximum solar-to-electric power conversion efficiency of 6.4 % was achieved by the DSSC fabricated using ZnONP photoanode, which also had an open-circuit voltage of 0.52 V, a short-circuit current of 54 mA/cm², and a fill factor of 0.57. The photovoltaic performance measurements demonstrated promising power conversion efficiency. This study affirms the dual purpose of Syzygium malaccense leaf extract-mediated ZnO NPs for UV-assisted photodegradation of NEO in wastewater and as a photoanode in DSSCs.These findings underscore the multifunctionality of the synthesized nanomaterial for environmental remediation purposes and solar energy harvesting.