Tiling of Solar Cell Surfaces: Influence on Photon Management and Microstructure

Microcrystalline silicon thin‐film solar cells prepared on hexagonal tiled surfaces exhibit record short‐circuit current densities and energy conversion efficiencies. However, it remains unclear if hexagonal textured substrates represent the best possible substrate tiling. In this study, hexagonal tiled substrates are compared with square and triangular tiled substrates in terms of photon management and microstructure. The 3D interface morphology of the individual layers of the solar cells is calculated and used as input parameters for the prediction of microcracks in the film and the simulation of 3D optical wave propagation. A comparison of the calculated interface morphologies with experimental results exhibits a good agreement for solar cells on hexagonal textured substrates, permitting calculations for solar cells on square and triangular textured substrates. The investigation of the crack formation process indicates that the square and the triangular textured substrates are superior to the hexagonal textured substrates. Finally, crack‐free triangular textured solar cells exhibit increased short‐circuit current densities compared to hexagonal and square textured solar cells.