Designing functional Σ13 grain boundaries at seed junctions for high-quality cast quasi-single crystalline silicon

Dislocation clusters and sub-grain boundaries (Sub-GBs) induced by the misorientation between adjacent seeds are destructive to the quasi-single crystal (QSC) Si ingot quality and the solar cell efficiency. Here, we have designed an artificial Sigma 13 GB between two adjacent < 100 > -oriented seeds at the crucible bottom. It is found that the generation of dislocation clusters and sub-GBs from the seed junctions is significantly suppressed owing to the low energy barrier potential of the Sigma 13 GB. Although some twins could generate from the vertical Sigma 13 GB, they will not give a bad influence on the ingot quality. The efficiency of solar cells is absolutely high in industrial circles, with an average value of 20.1%. These results pave a new way to the fabrication of high quality QSC-Si ingots for photovoltaic application.