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Light Management in Thin Crystalline Silicon Solar Cells
E.S. Marstein, J.H. Selj, J. Gjessing, H. Haug, A. Sudbø
Anti-Reflection Coating, Light Trapping, Porous Silicon, Crystalline Silicon
Wafer-Based Silicon Solar Cells and Materials Technology
Subtopic: Silicon Solar Cell Improvements
Event: 27th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2CV.7.22
2049 - 2052
ISBN: 3-936338-28-0
Paper DOI: 10.4229/27thEUPVSEC2012-2CV.7.22
0,00 EUR
Document(s): paper


In order to reduce the costs of solar cells, there is a strong drive towards the use of thinner absorber materials. Crystalline silicon materials have already proven highly attractive as absorbers in mass produced, low cost and efficient solar cells. However as absorbers become thinner, crystalline silicon solar cells increasingly suffer from optical losses related to transmission, which again lead to losses in short circuit current density and efficiency. In this work, recent developments of structures for managing light in co-planar, ultrathin crystalline silicon substrates made in our research group are presented. We show that the light trapping can be dramatically enhanced in ultrathin crystalline silicon wafers by incorporating periodic nanostructures on a solar cell rear side covered with a surface-passivating dielectric material and a metal mirror. To allow for simplified module and solar cell processing with such structures, we have aimed at developing a co-planar solar cell structure. Unfortunately, without proper measures, the resulting increases in front side reflectance will cancel out any gain in light trapping. We will therefore also show that a multilayer thin film anti-reflection coating (ARC) structure with properly designed gradients in refractive index can sufficiently reduce front side reflection in a solar cell and module environment.