Laser-doped metal-plated bifacial silicon solar cells

In this paper we report on the fabrication of laser-doped p-type bifacial cells using self-aligned metal-plating with energy conversion efficiencies as high as 19.2%. A key fabrication step for these cells is recognising that the p-type silicon regions can be made cathodic by forward biasing the p–n junction in a process which we call here field-induced plating (FIP). Used in conjunction with light-induced plating (LIP) in the same plating apparatus, FIP can be used to form low cost nickel/copper grids on both surfaces of a cell. Furthermore, the simplicity of the FIP process means that it can potentially be performed using the same plating equipment and chemistry as used for LIP. Plating rates similar to LIP were achieved (i.e., ~10 µm of copper in 10 min), however there is potential to plate at much faster rates with FIP because the junction is forward-biased. This bifacial cell plating method could be adapted to metallise a range of bifacial cells including heterojunction cells.