MC-silicon solar cells with >17% efficiency

In a study we applied different solar cell processes of varying complexity to several different directionally solidified mc-Si materials. The materials differed with respect to the crystallization velocity, planarity of the crystallization interface, and feedstock quality. In general, higher solar cell efficiencies were observed with increasing process complexity. Emitter passivated solar cells with integrated gettering yielded efficiencies up to 17.4% for materials with planar crystallization interface while materials with strongly bent crystallization interface seem to be more vulnerable to prolonged processing times and higher temperatures. The limiting factor for solar cell efficiency seems to be the grown-in quality of the silicon like homogeneity and defect density rather than the solar cell process itself.