Simple prism pyramids: a new light trapping texture for silicon solar cells

A new light trapping front surface geometry for solar cells, the simple prism pyramid (SPP) texture, is introduced and numerically analyzed with the newly developed ray tracing program SUNRAYS. The SPP texture is applicable to polycrystalline cells because it can be prepared by mechanical grooving. The SPP texture achieves the maximum average path length of rays that is theoretically possible under isotropic illumination. Encapsulated, 300 μm thick silicon solar cells with a grooving period of 100 μm and a flat aluminum back surface reflector are considered. The light trapping properties of symmetric upright grooves and pyramids are studied systematically as a function of facet orientation. The SPP texture is superior to both symmetric upright grooves and pyramids