Indium-free back-contacted silicon heterojunction solar cells approaching 27% conversion efficiency

Shi Yin, Chengjian Hong, Chunxiu Li, Ze Zhang, Miao Yang, Xiaoning Ru, Fuguo Peng, Minghao Qu, Qishu Xu, Po Fang, Hua Wu, Liang Fang, Junxiong Lu, Xixiang Xu Central R&D Institute, LONGi Green Energy Co., Ltd., Xi’an, Shaanxi, --, China

Heterojunction technology (HJT) exhibits high efficiency in silicon solar cells, thanks to the superior passivation quality of intrinsic amorphous silicon, but the debate regarding the impact of limited indium resources on its large-scale production has never stopped, especially when considering the future terawatt-scale. Following our previous 26.81% HJT record, all-back-contacted heterojunction solar cells (HBC) have been successfully developed due to its potential for higher efficiency and indium-free strategy was also considered to alleviate the anxiety for its scale production. X/Y-oxide (for proprietary reason) bilayer was adopted to substitute conventional tin-doped indium oxide for transparent conductor. After optimization on the process parameters and the thickness, 26.95%-efficiency HBC solar cell was produced with ISFH certification.