Optical Modeling of Honeycomb Textures for Multicrystalline Silicon Solar Cells
Honeycomb textures provide excellent reflectance reduction for multicrystalline silicon solar cells. Achieved reflectance levels are comparable or even superior to those of pyramidal textures for monocrystalline silicon. Honeycombs were used to achieve record efficiencies for multicrystalline silicon solar cells. In this paper, we present an analytical optical model for the calculation of the front surface reflectance of honeycomb-textured silicon wafer solar cells in air environment and in a module. Reflectance is calculated using an analytical path tracer for a geometric representation of the texture's symmetry. Light trapping in the module is calculated using a retro-reflection model. We evaluate the approach for a selected set bare and antireflection-coated samples against air and for encapsulated samples. For the used samples, we show that as little as 1% of the net incoming photons are reflected at the solar cell-air interface. Compared with state-of-the-art isotextures, the presented honeycomb textures reduce the net reflectance loss in a photovoltaic (PV) module from 0.8 to 0.3 mA/cm2.