Natural Waste to Electricity: Engineering Pomegranate Peels and Ag-Doped ZnO for Photovoltaic Applications

Abstract

Utilization of natural waste for energy conversion offers the method for clean energy production with sustainable development. The pomegranate peels are the natural waste generated every day and we describe the conversion of this waste into electricity by a simple and cost-effective method. Dye Sensitized Solar Cells (DSSCs) offer simple and cost-effective method for the preparation of solar cells. The advantages include easy to fabrication, lower cost of the materials and electricity generation under low illumination indoor conditions. DSSCs involve two Transparent Conducting Oxide (TCO) photoelectrodes acting as photoanode and photocathode. In one photoelectrode, Semiconducting oxide (TiO2/ZnO) and dye (Natural/Organometallic) are coated that acts as photo-absorbing materials. The role of dyes and semiconducting material play an important role in determining the photovoltaic conversion efficiency of fabricated solar cells. In this work, hydrothermal method has been adopted for the preparation of pure and silver doped ZnO nanoparticles using polyethylene glycol (PEG) as capping agent via wet chemical route. The structural and optical properties of the prepared samples were studied using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Analysis (EDAX) and UV-Visible absorption spectra. A Natural dye from the peels of pomegranate was extracted and dye sensitized solar cells were fabricated with pure and Ag-doped nanoparticles. Both the materials showed the photovoltaic conversion capabilities and showed photoconversion efficiencies. The solar cell fabricated with Ag-doped ZnO semiconducting nanoparticle showed higher short circuit current density as compared to the pure ZnO-nanoparticle synthesized in this study. The photoconversion efficiency of the DSSC based on Ag-doped ZnO showed 30% more conversion efficiency than the cell without silver doping.