Reflection reduction in silicon solar cells by means of laser and plasma treatment

Abstract

In order to ensure the competitiveness of photovoltaic systems in comparison to conventional fossil fuels, the production costs of the PV modules must be reduced and the efficiency of the solar cells increased. Therefore, silicon solar cells are structured for efficiency enhancement through absorption optimization by means of laser and plasma treatment.Anti-reflect layers on silicon solar cells lead to reduced reflections on the cell surface and thus to an increase in the efficiency of solar cells. In order to exploit the energy potential of solar radiation, reflection on solar cells must be further minimized and absorption maximized. To achieve minimum reflection and maximum absorption in silicon solar cells, surfaces of solar cells are processed by means of laser radiation and plasma etching methods. Processing with laser radiation allows a defined periodic microstructuring of the surface, which promotes the absorption of the energy-intensive components of the solar radiation. In a subsequent plasma etching process, a nanostructure is applied on this microstructure, which reduces the reflection. Together, this is a combination of superficial structures that increase the efficiency of silicon solar cells, without the need of anti-reflect layers. To achieve a minimum reflection and maximum absorption, polycrystalline silicon wafers sliced by slurry paste and diamond wire were treated with laser and plasma analyzed by UV/VIS spectroscopy and scanning electron microscopy.