n-type CZ-Si wafers featuring longer minority carrier lifetime and higher tolerance of certain metal contamination can offer one of the best Si-based solar cells. In this study, Si heterojuction （SHJ） solar cells wh...n-type CZ-Si wafers featuring longer minority carrier lifetime and higher tolerance of certain metal contamination can offer one of the best Si-based solar cells. In this study, Si heterojuction （SHJ） solar cells which was fabricated with different wafers in the top, middle and tail positions of the ingot, exhibited a stable high efficiency of〉 22% in spite of the various profiles of the resistivity and lifetime, which demonstrated the high material utilization of n-type ingot. In addition, for effectively converting the sunlight into electrical power, the pyramid size, pyramid density and roughness of surface of the Cz-Si wafer were investigated by scanning electron microscope （SEM） and transmission electron microscope （TEM）. Furthermore, the dependence of SHJ solar cell open- circuit voltage on the surface topography was discussed, which indicated that the uniformity of surface pyramid helps to improve the open-circuit voltage and conversion efficiency. Moreover, the simulation revealed that the highest efficiency of the SHJ solar cell could be achieved by the wafer with a thickness of 100 μm. Fortunately, over 23% of the conversion efficiency of the SHJ solar cell with a wafer thickness of 100 μm was obtained based on the systematic optimization of cell fabrication process in the pilot production line. Evidently, the large availability of both n-type ingot and thinner wafer strongly supported the lower cost fabrication of high efficiency SHJ solar cell.展开更多
文摘n-type CZ-Si wafers featuring longer minority carrier lifetime and higher tolerance of certain metal contamination can offer one of the best Si-based solar cells. In this study, Si heterojuction （SHJ） solar cells which was fabricated with different wafers in the top, middle and tail positions of the ingot, exhibited a stable high efficiency of〉 22% in spite of the various profiles of the resistivity and lifetime, which demonstrated the high material utilization of n-type ingot. In addition, for effectively converting the sunlight into electrical power, the pyramid size, pyramid density and roughness of surface of the Cz-Si wafer were investigated by scanning electron microscope （SEM） and transmission electron microscope （TEM）. Furthermore, the dependence of SHJ solar cell open- circuit voltage on the surface topography was discussed, which indicated that the uniformity of surface pyramid helps to improve the open-circuit voltage and conversion efficiency. Moreover, the simulation revealed that the highest efficiency of the SHJ solar cell could be achieved by the wafer with a thickness of 100 μm. Fortunately, over 23% of the conversion efficiency of the SHJ solar cell with a wafer thickness of 100 μm was obtained based on the systematic optimization of cell fabrication process in the pilot production line. Evidently, the large availability of both n-type ingot and thinner wafer strongly supported the lower cost fabrication of high efficiency SHJ solar cell.
