Comparative Study of ZnO Nanomaterials Synthesized by Green and Electrospinning Methods

Abstract

This article presents a comparative study between the ZnO nanocone and nanofibers. ZnO nanocones were synthesized through the green route, using Azadirachta indica leaf extract media, and ZnO nanofibers were synthesized by the electrospinning process. The microstructural parameters of the prepared nanomaterials were investigated using powder X-ray diffractometer (XRD) and Rietveld refinement analysis. The XRD patterns confirmed the formation of single-phase ZnO with hexagonal wurtzite structure having an average crystallite size of 21 nm and 54 nm for the conical and fibrous nanoparticles, respectively. The field emission scanning electron microscopy revealed that the mean radius of nanofibers was 25-30 nm while the mean height and mean base radius of nanocones were 181 nm and 91 nm respectively. Elastic properties were estimated using elastic compliances S11 (6.0678×10-12 m2N-1), S12 (-2.2602×10-12 m2N-1), S13 (-1.3579×10-12 m2N-1), S33 (5.5196×10-12 m2N-1) and S44 (22.6833×10-12 m2N-1) which were calculated using the THERMO-PW code, based on the density functional theory. The calculated elastic constants of the two nanostructures yielded similar values as expected. However, the elastic limit of the two nanostructures differs due to their morphological anomaly. Moreover, the optical bandgap of nanofibrous ZnO was lower than that of nanoconical ZnO.