具有选择性前表面场的p型背结太阳电池

p-Type Back-Junction Solar Cells with Selective Front Surface Field

隧穿氧化物钝化接触(TOPCon)结构由掺杂多晶硅及隧穿氧化层构成,具有出色的钝化及接触特性。将n型TOPCon太阳电池制备理念应用到p型硅片中,利用背面原位掺杂磷多晶硅层充当pn结,并利用印刷纳米硼浆的方法完成选择性前表面场(FSF)的制备。这种具有选择性前表面场的p型背结电池的优势是背面TOPCon发射极的全面积金属接触避免了发射极内的横向电流传输损耗,有助于空穴(主要载流子)向前端的局部前表面场传输,另外正面选择性前表面场的设计形成高低结,极大地减小了表面复合及金属栅线接触电阻。结果表明,相比同结构的n型TOPCon太阳电池,此种结构的p型背结太阳电池光电转换效率高0.34%,填充因子约高1%,说明该结构的背结太阳电池具有一定的电性能优越性和发展潜力。

The tunneling oxide passivation contact(TOPCon)structure is composed of doped polysilicon and tunneling oxide layers,and has excellent passivation and contact characteristics.The preparation concept of the n-type TOPCon solar cell was applied to p-type silicon wafers,the backside in situ doped phosphorus polysilicon layer was used as a pn junction,and the selective front surface field(FSF)was prepared by printing nano-boron paste.The advantage of the p-type back-junction cell with selective front surface field is that the full-area metal contact of the backside TOPCon emitter avoids lateral current transport loss within the emitter,conducing to the transport of holes(primary carriers)to the local front surface field at the front end.Besides,the design of the front selective front surface field forms a high and low junction,thus greatly reducing the surface recombination and metal gate line contact resistance.The results show that the photoelectric conversion efficiency and the fill factor of the p-type back-junction solar cell with the structure are 0.34%and about 1%higher than those of the n-type TOPCon solar cell with the same structure,indicating that the back-junction solar cells with the structure has certain electrical performance superiority and development potential.