Fabrication of 25.1% Efficient Hetero Junction Back Contact Si Solar Cells by Mass-Production Process

We have developed a mass-production process of high efficiency hetero junction back contact (HBC) solar cell by using interdigitated back contact (IBC) solar cell patterning technology innovated by Sharp Corporation. A HBC solar cell with conversion efficiency (Eff) of 25.09% has been confirmed at a full cell size of 240.6cm ² , short circuit current density ($J _{sc}$) of 41.19 mA/cm ² , open circuit voltage ($V _{oc}$) of 738.5 mV and 82.48% fill factor (FF) are achieved. As a result of analyzing the current density-voltage (J-V}) data by a standard one diode equation, the series resistance as low as 0.107 $\Omega {\bf cm^{2}}$ was extracted. The surface mount technology (SMT) used for modularization of HBC contributes to the low series resistance. By using the IBC patterning process, the production cost of HBC solar cells is reduced. We have successfully established mass-production process for low-cost and high-efficiency HBC solar cells.