Reconfiguring the Band-Edge States of Lead-Halide Perovskite Semiconductors
Feb. 25, 2021
We report a π-conjugation-induced extension of electronic states of A-site cations that impacts perovskite frontier orbitals. The π-conjugated pyrene-containing A-site cations electronically contribute to the surface band edges and impact the carrier dynamics with a properly tailored intercalation distance between the inorganic framework. The ethylammonium pyrene increased hole mobilities, improved power conversion efficiencies relative to a reference perovskite, and also improved device stability.
Scientific Achievement
We showed that appropriately functionalized pyrene organic cations contribute to the band-edge states in lead (Pb)-halide perovskite semiconductors and improves surface carrier dynamics.
Significance and Impact
Surfaces and interfaces drive photoconversion and help protect the underlying bulk material. Molecules that can couple electronically to the underlying material provide additional design rules for controlling opto-electronic behavior.
Research Details
- Three pyrene derivatives with different ammonium anchor groups
- Photoelectron spectroscopy and theory demonstrate coupling of band-edge states with perovskite states
- Measured impact on carrier dynamics and solar cells
Related People
Kai Zhu
National Renewable Energy Laboratory
Matthew Beard
National Renewable Energy Laboratory
Yanfa Yan
University of Toledo
Three A-site pyrene derivatives terminate perovskite films with different length of the anchor ammonium functional group. Both photoelectron and spectroscopy theory show that different anchoring groups modifies how pyrene moiety couples to the inorganic lattice.
