Green Synthesis, characterization of Zinc oxide nanoparticles using Chromolaena odorata extract and evaluation of its properties for photoanode of solar cells

Abstract

Synthesis of Zinc oxide nanoparticles (ZnONPs) using plant extract was carried out in this work because of its advantages over other method of synthesis namely; simplicity, environmental friendliness and elimination of toxic chemicals. Fresh Siam leaf extract was characterized over a period of 10 days to study the effect of time on the optical photon energy absorption properties. ZnONPs was synthesized and deposited on substrate by spin-coating method and characterized by UV-vis spectroscopy, Fourier transform infra-red spectroscopy, Scanning Electron microscopy, and Energy Dispersive X-ray. ZnONPs thin film device was then fabricated to study the electrical properties. From UV-vis spectroscopic result, as the time (day) increased, there was an increase in the value of the transmittance and corresponding reduction in photon energy absorption. FTIR result gives the functional groups and absorption number at 3448.04cm⁻¹ O-H single bond, 2524.85cm⁻¹ C-H bond, 1437.15 cm⁻¹, 880.59 cm⁻¹, 729.06 cm⁻¹, 433.44 cm⁻¹ Zn-OH and Zn-O variety of single bond. The surface morphology shows large grain size. Energy band gap of ZnONPs was approximately 3.7 eV. The fabricated ZnONPs thin film device under illumination has efficiency of 2.01⁰/₀. From the morphology, optical, and electrical properties of the ZnONPs thin film and device, it could be a suitable material for crystalline solar cells as photoanode.