Optical Design of Inverted Pyramid Textured PERC Solar Cells

Single side optical design of solar cells has limitations. In this paper, we studied the optical properties of inverted pyramid textured passivated emitter and rear cell (PERC) solar cells, considering different combinations of front and rear inverted pyramid angles. Ray tracing simulations were conducted to obtain a macro insight, and then experiments were performed under the conditions of practical applications. According to an analysis of the results, the overall optical properties are shown to be positively correlated to the front side inverted pyramid angle, and the influence of the rear side inverted pyramid angle strongly depends on the front side inverted pyramid angle. In practical applications, double-sided inverted pyramids with an angle of 54.74° can be efficiently fabricated on silicon wafers etched by the metal catalysis chemical etching (MCCE) method. Maintaining the front surface morphology as etched, wafers with small-angle (10°-20°) inverted pyramids at the rear side has an ∼1.66% improvement in optical gain compared with totally planarized rear side wafers; meanwhile, the rear side passivation effect does not change much. Thus, it is a better choice to have small-angle structures on the rear side. Our results could serve as a guide for the texturization and rear side polishing of inverted pyramid textured PERC solar cells.