Excitations Partition into Two Distinct Populations in Bulk Perovskites
Abstract
Organolead halide perovskites convert optical excitations to charge carriers with remarkable efficiency in optoelectronic devices. Previous research predominantly documents dynamics in perovskite thin films; however, extensive disorder in this platform may obscure the observed carrier dynamics. Here, carrier dynamics in perovskite single‐domain single crystals is examined by performing transient absorption spectroscopy in a transmissive geometry. Two distinct sets of carrier populations that coexist at the same radiation fluence, but display different decay dynamics, are observed: one dominated by second‐order recombination and the other by third‐order recombination. Based on ab initio simulations, this observation is found to be most consistent with the hypothesis that free carriers and localized carriers coexist due to polaron formation. The calculations suggest that polarons will form in both CH3NH3PbBr3 and CH3NH3PbI3 crystals, but that they are more pronounced in CH3NH3PbBr3. Single‐crystal CH3NH3PbBr3 could represent the key to understanding the impact of polarons on the transport properties of perovskite optoelectronic devices.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 09, 2018
- Source ID
- 10.1002/adom.201700975
Entities
People
- David M Tiede
- Giulia Galli
- Gregory S. Engel
- John P Otto
- L. Wang
- Márton Vörös
- Nicholas E. Williams
- Nicholas P Brawand
- Peter D. Dahlberg
Organizations
- Air Force Office of Scientific Research
- Alfred P. Sloan Foundation
- Argonne National Laboratory
- Defense Threat Reduction Agency
- Division of Materials Research
- National Institute of Biomedical Imaging and Bioengineering
- National Institutes of Health
- The Camille and Henry Dreyfus Foundation
- United States Department of Energy
- University of Chicago