<p>The study aims to investigate an eco-friendly approach for synthesizing metal oxide (MO) nanoparticles by using banana peels (bp) as a sustainable and natural source. In this research, banana peel extract was used to synthesize copper oxide (CuO), nickel oxide (NiO), zinc oxide (ZnO), iron oxide (Fe₃O₄), and magnesium oxide (MgO) nanoparticles. The prepared materials were sintered in a muffle furnace at 400&#xa0;°C for 4&#xa0;h. The structural characterization of the synthesized materials was carried out using X-ray diffraction (XRD), Fourier transfer-infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). The results indicates the successful formation of metal oxides with crystallite size ranging from 9 to 16&#xa0;nm. Additionally, the calculated values of optical band gaps derived from UV–visible spectroscopy (UV–Vis), along with color rendering index (CRI) and correlated color temperature (CCT) values obtained from fluorescence spectroscopy (FL) demonstrated their potential for applications in optoelectronics and photosynthetically active radiation (PAR). The results also highlighted the impedance spectroscopy where the Nyquist plot indicates the contribution of grain and grain boundary resistance. The plots of AC conductivity reveal with NiO exhibiting high conductivity compared to other metal oxides making the material also suitable for energy storage application.</p> Graphical abstract <p></p>