High efficiency 4-terminal perovskite/c-Si tandem cells

The perovskite/c-Si tandem technology is considered as a cost-effective approach to realize a cell efficiency beyond the limit of single-junction (SJ) c-Si cells. Compared to its counterpart of 2-terminal (2T) configuration, 4-terminal (4T) tandem has the advantages such as no constraint of current matching and potentially simple mechanical stacking. But one of the largest challenges is the limited near-infrared (NIR) transmission of the semi-transparent perovskite solar cell (ST-PSC), which has been a bottleneck to the c-Si bottom cell performance and eventually the whole tandem cell performance. The highest NIR transmittance that has been reported is about 84%. In this contribution, we demonstrate a p-i-n planar ST-PSC with an efficiency as high as 15.7% and with a record NIR transmittance of about 92%. It is realized by optimization of the tin-doped indium oxide (ITO) material properties and light management. This NIR-transparent and high-efficiency ST-PSC leads to a 4T tandem cell efficiency of 25.7%, using an interdigitated-back-contact (IBC) c-Si bottom cell.