Pyrolysis of Carbon-Doped ZnO Nanoparticles for Solar Cell Application

Abstract

It is very important to find new methods for improving the properties of nanostructured materials that can be used to replace the highly expensive and compli-cated techniques of fabricating ZnO nano-powders for solar cell applications. Pneumatic spray pyrolysis method offers a relatively inexpensive way of fabricating ZnO nanomaterials of controllable morphology, good crystallinity and uniform size distribution, which makes it a good candidate for the production of ZnO nanoparticles. Additionally, it has the advantage of producing ZnO NPs in one step directly on the substrate without the need for other wet chemistry processes like purification, drying and calcination. To that end, the present study emphasizes more on the design and optimization of spray pyrolysis system as well as on the pneumatic spray pyrolysis conditions for the production of carbon-doped ZnO nanoparticles. The un-doped and carbon-doped ZnO NPs were prepared using pneumatic spray pyrolysis employing zinc acetate as a precursor solution and tetrabutylammonium as a dopant. The fabricated un-doped and C-ZnO NPs were characterized for their morphological, structural and optical properties using SEMEDX, XRD and DRS. SEM analysis has revealed that the fabricated un-doped and C-ZnO NPs have spherical shape with mesoporous morphology. The cross-sectional SEM has also revealed that the film thickness changes with increasing dopant concentration from 0.31 to 0.41 μ m at higher concentrations. Moreover, the EDX spectra have confirmed the presence of Zn and O atoms in the PSP-synthesized ZnO NPs. XRD analysis of both un-doped and C-ZnO has revealed the peaks belonging to hexagonal Wurtzite structure of ZnO. Additionally, the DRS has revealed a decrease in energy band gap of the synthesized ZnO NPs, with the increase in carbon dopant level.