Investigating the effect of sol–gel solution concentration on the efficiency of silicon solar cells: role of ZnO nanoparticles as anti-reflective layer

Abstract

In this research, the use of ZnO thin films, as anti-reflective layers of solar cells, is presented. The thin films were synthesized through a sol–gel method and then deposited on a P–N silicon substrate using the spin-coating technique. The effect of the ZnO thin films on the efficiency of a solar cell piece was then investigated. To synthesize the ZnO films, zinc acetate dihydrate was used as the precursor, monoethanolamine (MEA) was employed as the stabilizer, and 2-methoxyethanol was used as the solvent. Moreover, to investigate the effect of the sol–gel solution concentration on the formation of ZnO nanoparticles, samples with various concentrations were prepared, and after deposition, the solar cell piece was fabricated. The ZnO thin films prepared were characterized using X-ray diffraction and field-emission-scanning electron microscopy, and a four-point probe was used to measure the surface resistance of the sample. The obtained results indicated that the nano-structured ZnO films with hexagonal crystallites and 30–50 nm particle sizes were successfully formed on the silicon substrate. In addition, the observations unraveled that the coated ZnO films could act as anti-reflection films improving the efficiency of silicon solar cells. All in all, it was concluded that the concentration of the sol–gel solution could have a considerable effect on the efficiency of the silicon solar cell.