In 2019, Fraunhofer ISE increased the efficiency of N-type TOPCon solar panel cells to 25.8%, setting a new efficiency record for N-type TOPCon solar modules cells.

In 2020, Fraunhofer ISE further optimized the recombination loss and lateral transfer resistance loss of the emitter on a 25.8% efficiency cell, placing the n+ TOPCon on the backside of the P-type silicon substrate as the emitter, creating a TOPCon solar panels cell with a conversion efficiency of 26% world efficiency.

During this period, the German Institute for Solar Energy Hamelin (ISFH) also tried to combine the TOPCon structure with good passivation performance with IBC cells in 2014, and first proposed POLO-IBC with 722 mV open circuit voltage and 23.9% conversion efficiency (TOPCon structure IBC) cell [3], and increased the efficiency of POLO-IBC battery to 26.1% in 2018, creating a world efficiency record for TOPCon structure IBC cells.

POLO-IBC cell structure diagram & world efficiency record POLO-IBC cells structure diagram.