Capacitive and Bioenzymevoltaic Characteristics of Photosynthetic Chromolena Odorata – Nanostructured Zinc Oxide System

Abstract

Zinc Oxide nanoparticles (ZnO) have been successfully synthesized by a chemical method at a low temperature of 60°C and dried at 80°C. The matching of the observed 2 q value with the JCPDS value of the XRD pattern showed that ZnO was synthesized. The pattern obtained showed high peaks as an indication of crystallinity at low temperature without annealing. The average grain size of the crystal obtained using Debye scherrer formular is 18.6 nm. The crystal structure lattice system is hexagonal wurzite structure. The SEM images obtained showed that the material is made up of agglomerated grains resulting in nanostructured islands. The direct optical band gap was obtained using Tauc’s relationship to be 2.4 eV. A bioenzymevoltaic cell was developed in form of a Dye Sensitized Solar Cell but with a photosynthetic material: Chromolaena Odorata acting as both the dye and the electrolyte. The short circuit current of 1.5 mA and open circuit voltage of 170 mV were obtained for the continuous and residual energy on the system. We found that the device exhibited a bio-capacitive effect, as the photosynthetic material generates electron and the energy is being stored in the system as much as 39 mA with a corresponding voltage of 196 mV.