There are various ways to build a solar cell based on crystalline silicon. The main one used to be the “PERC” cell concept, a pragmatic compromise between efficiency and simplicity. However, efficiency was only achieved slowly after a lot of hard work.
One of the most promising candidates is the “TOPCon” cell concept, which improves efficiency levels in mass production.
At first glance, a TOPCon solar cell installed in a module is indistinguishable from its PERC counterpart. The key differences are to be found inside: The TOPCon solar cell is made from n-doped silicon, which poses more of a challenge in the manufacturing process than the p-doped material used for a PERC cell but allows higher degrees of efficiency.
Another major difference is that the passivation process is more laborious for TOPCon solar cells but achieves a greater effect. In particular, passivating the rear side with a layer of polycrystalline silicon requires a lot of technical effort but allows the solar cell to handle higher voltages, thus increasing efficiency.
