Potential for Photovoltaic Cell Material by Green Synthesis of Silicon Carbide from Corn Cob through Magnesiothermic Reduction

Abstract

Corn cobs can be processed chemically to generate new products for electricity employing a simple, low-cost, and environment friendly method. In this article, silicon carbide (SiC) and activated carbon can be synthesized from corn cobs via sol–gel and a chemical activation method, respectively. SiC was synthesized by reacting the synthesized silica and activated carbon with magnesium powder, which served as catalyst at 600 oC. The SiC was doped with varying amount of Al2O3 (0.01, 0.015, 0.02 and 0.1 g), a p-type dopant, via solvothermal synthesis. The undoped SiC was characterized using Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX) and Fourier Transform Infrared (FTIR). Then, the band-gap energy and conductivity of undoped SiC and p-doped SiC were determined. SEM-EDX and FTIR analysis confirmed the presence of Si–C bond in the synthesized SiC from corn cob. It was observed that p-doped SiC absorbs higher energy in the visible region than undoped SiC. FTIR analysis confirmed the incorporation of the aluminum in the SiC. UV–vis spectroscopy confirmed that the synthesized p-doped SiC exhibits higher absorbance compared with undoped SiC. Aluminum doping also increased absorption bands on the visible region making it more efficient for potential application in photovoltaic (solar) cells because of the decreased band-gap energy and increase in conductivity of p-doped SiC. The ratio of 1:1–2 (SiC:Al) showed the lowest band-gap and highest conductivity with a value of 1.57–1.58 eV and 0.080–0.082 mS/cm compared with the amount of other p-dopants. Statistically, it was found that the 1:1–2 ratio of SiC:Al can be an effective p-junction for the application in photovoltaic (solar) cells.