Light trapping and reflection control with tilted pyramids and grooves

Texturing the surface of a cell to produce crystallographically defined pyramids and grooves is a well-established technique for improving the performance of crystalline solar cells. The double bounce experienced by reflected light with such textured surfaces reduces reflection to low levels even without antireflection coatings. A simply implemented approach based on tilting these geometrical features is shown to produce quadruple bounces in encapsulated cells. This reduces reflection from the cell surface from 3-4% without antireflection coatings to below 0.2%. Tilting of the geometrical features allows very effective light trapping within the cell when combined with a planar rear surface. The improved reflection properties are relevant to all cells which use texturing, regardless of their design.