Modelling isotextured silicon solar cells and modules

Abstract

We describe a one dimensional model for isotextured silicon solar cells.Combined optical and recombination analyses provide the tools required to predict the performance of isotextured cells; the utility of these tools is demonstrated by comparison with industrially fabricated screenprinted cells with full area back surface field. In this particular demonstration, inaccurate predetermination of front surface recombination reduces the predictive capability of the model. We measure the angular distribution of light from isotextured surfaces, showing that, when encapsulated with typical pottants beneath glass, current generation in isotextured cells approaches 99% of that achieved in random pyramid textured equivalents. This represents a reduction in the performance difference between the two textures when operating in air (not encapsulated); in this case, current generation in an isotextured device is 96% of that calculated beneath random pyramids. We calculate the short circuit current of photovoltaic modules comprising cast-mono silicon solar cells; when encapsulated beneath glass and EVA, isotexturing, rather than alkaline etching, maximises photogeneration in cells with less than 84% monocrystalline (<100>) surface area.