Synthesis of zinc oxide films by sol-gel method and its application to improve the efficiency of silicon solar cells

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. also in order to investigate the effect of concentration of sol-gel solution in formation of ZnO nanoparticles, samples with various concentrations were prepared and after deposition, solar cell piece was fabricated. The ZnO thin films prepared were characterized using X-ray diffraction and field emision-scanning electron microscopy, and a four-point probe was used to measure the surface resistance of the sample. Moreover, to evaluate the electrical properties of the solar cell piece, first, the back and front metal connections of the solar cell were installed using the stencil silk-screen printing method and then a solar simulator was used. 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. Also, the observations unraveled that the coated ZnO films could act as an anti-reflection films and improved the efficiency of silicon solar cells. In addition, the results showed that the concentration of the sol-gel solution can have a considerable effect on the efficiency of the silicon solar cell.