Practical high efficiency bifacial solar cells

In this paper, we present a practical process to obtain bifacial Si solar cells. These cells are made using p⁺nn⁺ structure on high-medium base resistivity, continuous emitters and with a process that maintains high bulk minority carrier lifetime. Efficiencies of 19.1% and 18.1% are achieved under standard conditions when the cell is illuminated by n⁺n high-low junction and when it is illuminated by p⁺n junction, respectively. We show that the n⁺n high-low junction provides a higher current density and a good ratio between generated current of each face is found to be of about 103%