Journal Article

Carrier lifetimes of >1 μs in Sn-Pb perovskites enable efficient all-perovskite tandem solar cells

Palmstrom, Axel F., Li, Zhen, Zhao, Dewei, van Hest, Maikel F. A. M., Beard, Matthew C., Kim, Dong Hoe, Chen, Cong, Shaheen, Sean E., Reese, Matthew O., Christensen, Steven T., Chen, Xihan, Berry, Joseph J., Zhu, Kai, Reid, Obadiah G., Dunfield, Sean P., Tong, Jinhui, Harvey, Steven P., Zhang, Fei, Ndione, Paul F., Teeter, Glenn, Liu, Jun, Song, Zhaoning, Al-Jassim, Mowafak M., Yan, Yanfa

2019

Overview

All-perovskite–based polycrystalline thin-film tandem solar cells have the potential to deliver efficiencies of >30%. However, the performance of all-perovskite–based tandem devices has been limited by the lack of high-efficiency, low–band gap tin-lead (Sn-Pb) mixed-perovskite solar cells (PSCs). We found that the addition of guanidinium thiocyanate (GuaSCN) resulted in marked improvements in the structural and optoelectronic properties of Sn-Pb mixed, low–band gap (~1.25 electron volt) perovskite films. The films have defect densities that are lower by a factor of 10, leading to carrier lifetimes of greater than 1 microsecond and diffusion lengths of 2.5 micrometers. These improved properties enable our demonstration of >20% efficient low–band gap PSCs. When combined with wider–band gap PSCs, we achieve 25% efficient four-terminal and 23.1% efficient two-terminal all-perovskite–based polycrystalline thin-film tandem solar cells.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science,AAAS
• Subject: Carrier lifetime / carrier lifetimes / Charge efficiency / Current carriers / Energy gap / Lead / MATERIALS SCIENCE / Micrometers / Optoelectronics / perovskite films / Perovskites / Photovoltaic cells / Polycrystals / Silicon / Solar cells / SOLAR ENERGY / Thin films / Thiocyanates / Tin