Development of hetero-junction a-Si/c-Si based on metal-wrap through structure solar cells

Abstract

How to further enhance the efficiencies of the silicon solar cells which can be applied into commercial production for the next generation is a most important issue. On the way to achieving higher efficiencies, back contact solar cells and heterojunction solar cells seem to be very promising. Therefore, we proposed a amorphous/crystal hetero-junction with metal-wrap structure (HJ-MWT) which combines the advantages of different high-efficiency concepts such as back contacts, and great heterojunction passivation. The advantages of MWT are less shadowing loss and lower module electrical power losses. It will increase 1.5–3 % module conversion efficiencies compared to conventional silicon solar cells. Furthermore, the other advantage of MWT isn't fully limited by the bulk lifetime and carrier diffusion lengths contrast to IBC solar cells. It doesn't need very-high-quality silicon wafer(minority lifetime> 1ms). We proposed amorphous silicon or insulation materials were designed as electrical insulation layers within the via(wrap-through holes) to avoid shunt current occurring. The fabricating process flow that realizes HJ-MWT solar cells, with only 2–3 additional processes steps compared to conventional HIT solar cells. It's suitable to the mass production associated the cost consideration in the future. Before experiments, we used the software tool to do the two-dimension simulation with HJ-MWT structures. From theoretical calculation, we found HJ-MWT solar cell efficiencies increased up to 0.6% compared with conventional HIT solar cells. We have also done the further experimental investigation on new proposed HJ-MWT structures and corresponding data will be published in this conference. It shows the HJ-MWT solar cell has the potential to further increase the efficiencies of solar cell and solar panels in the future.