Abstract: A photovoltaic solar cell module comprises a plurality of bifacial solar cells and electrical conductors. Each bifacial solar cell comprises a plurality of bus-bar contacts. A phosphorous silicon glass layer is formed on one side of the bifacial cell by phosphorous diffusion, and a boron silicon glass layer is formed on the other side of the bifacial cell by boron diffusion. The phosphorous diffusion and the boron diffusion are conducted by a face-to-face diffusion method. The combination of the two gettering methods substantially increases the minority carrier life time of the bifacial solar cell.

Abstract: It is an object of the present invention to provide a silicon solar cell with n+pp+ BSF structure using solar grade silicon substrate, having a life time close to the initial level of the substrate. The solar cell of the present invention is produced by a back side boron diffusion step for diffusing boron on a back side of the substrate, a front side phosphorus diffusion step for diffusing phosphorus on a front side of the substrate, a low-temperature annealing step for annealing the substrate at 600° C. or lower for 1 hour or more, and an electrode firing step carried out at a peak temperature of 700° C. or lower for 1 minute or less, carried out in this order.

Abstract: It is an object of the present invention to provide a silicon solar cell with n+pp+ BSF structure using solar grade silicon substrate, having a life time close to the initial level of the substrate. The solar cell of the present invention is produced by a back side boron diffusion step for diffusing boron on a back side of the substrate, a front side phosphorus diffusion step for diffusing phosphorus on a front side of the substrate, a low-temperature annealing step for annealing the substrate at 600° C. or lower for 1 hour or more, and an electrode firing step carried out at a peak temperature of 700° C. or lower for 1 minute or less, carried out in this order.