Carrier Lifetimes of >1 ms in Sn-Pb Perovskites Enable Efficient All-Perovskite Tandem Solar Cells
May 3, 2019
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- eV) perovskite films.
We demonstrate for the first time extraordinarily long carrier lifetime (>1 µs) and diffusion length (~2.5 µm) in tin-lead (Sn-Pb) mixed low-bandgap (~1.25-eV) perovskite films achieved via novel solution chemistry based on GuaSCN.
Significance and Impact
GuaSCN additive induces formation of 2D barrier on grain surface, which suppresses oxidation of Sn2+, reduces defect density, and enables our demonstration of >20%-efficient Sn-Pb mixed perovskite solar cells and 25%-efficient all-perovskite tandem cells.
- Solution processing to prepare low-bandgap (1.25-eV) (FASnI3)0.6(MAPbI3)0.4 perovskite thin films
- GuaSCN additive to tune perovskite film formation and optoelectronic properties
- Detailed spectroscopic and electrical measurements to understand carrier dynamics and defect properties