27%-efficiency silicon heterojunction cell with 98.6% cell-to-module ratio driving new momentum towards the 29.4% limit
Zhigang Xie, Haiming Lu, Guangtao Yang, Zhan Gao, Kun Zhu, Yongheng Wang, Zibo Meng, Cong Guo, Haiyang Pei, Qianqian Jiang, Hongwei Li, Shu Zhang, Haiyuan Chu, Xue Chen, Yifeng Chen, Jifan Gao
Abstract
Silicon heterojunction technologies based on both-sided nanocrystalline contact layers currently offer the best passivation for commercial solar cells. We further improved this structure with rear-side polishing and progressive RF/VHF PECVD film deposition methods for doping layers, enabling high-pace mass production while maintaining notable passivation quality. Following this optimization, a certified cell efficiency above 27.0% and a fill factor of 87.06% are achieved on a large-area rectangular wafer (210 mm half-cell). With a multibusbar round-ribbon (smart-wire) design, we demonstrate a certified module efficiency of 25.44% and a module fill factor above 86% (for the first time) under a masked area of 1.63 m2, which is on par with the current world record module efficiency typically held by back-contact cell structures. Remarkably, the high VOC × FF value of 0.652–0.655 V was backed by a solid cell-to-module ratio of 98.6%. With respect to silicon single-junction solar cells, this work demonstrates significant progress toward Auger recombination dominance, a factor that is more critical than reducing front-side optical shading to approach the 29.4% efficiency limit. Achieving efficiency by approaching the theoretical limit in silicon heterojunction solar cells remains challenging. Here, the authors fabricate devices using rear-side polishing and progressive RF/VHF PECVD film deposition schemes for doping layers, realizing a certified cell efficiency of 27.0%.