Monolithic wide band gap perovskite/perovskite tandem solar cells with organic recombination layers

Journal article

We demonstrate a monolithic tandem solar cell by sequentially depositing a higher-bandgap (2.3 eV) CH3NH3PbBr3subcell and a lower-bandgap (1.55 eV) CH3NH3PbI3subcell bandgap perovskite cells, in conjugation with a solution-processed organic charge carrier recombination layer, which serves to protect the underlying subcell and allows for voltage addition of the two subcells. Owing to the low-loss series connection, we achieve a large open-circuit voltage of 1.96 V. Through optical and electronic modeling, we estimate the feasible efficiency of this device architecture to be 25.9%, achievable with integrating a best-in-class CH3NH3PbI3sub cell and a 2.05 eV wide bandgap perovskite cell with an optimized optical structure. Compared to previous reported all-perovskite tandem cells, we solely employ Pb-based perovskites, which although have wider band gap than Sn based perovskites, are not at risk of instability due to the unstable charge state of the Sn2+ion. Additionally, the bandgap combination we use in this study could be an advantage for triple junction cells on top of silicon. Our findings indicate that wide band gap all-perovskite tandems could be a feasible device structure for higher efficiency perovskite thin-film solar cells.

Authors: Sheng, R; Hörantner, M; Wang, Z; Jiang, Y; Zhang, W

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: Journal of Physical Chemistry C
• Volume: 121
• Issue: 49
• Pages: 27256-27262
• Publication date: 2017-09-19
• Acceptance date: 2017-09-19
• DOI: 10.1021/acs.jpcc.7b05517
• EISSN: 1932-7455
• ISSN: 1932-7447
• Keywords: Journal Article