Effect of Anisotropic Confinement on Electronic Structure and Dynamics of Band Edge Excitons in Inorganic Perovskite Nanowires
Abstract
Inorganic lead halide perovskite nanostructures show promise as the active layers in photovoltaics, light emitting diodes, and other optoelectronic devices. They are robust in the presence of oxygen and water, and the electronic structure and dynamics of these nanostructures can be tuned through quantum confinement. Here we create aligned bundles of CsPbBr3 nanowires with widths resulting in quantum confinement of the electronic wave functions and subject them to ultrafast microscopy. We directly image rapid one-dimensional exciton diffusion along the nanowires, and we measure an exciton trap density of roughly one per nanowire. Using transient absorption microscopy, we observe a polarization-dependent splitting of the band edge exciton line, and from the polarized fluorescence of nanowires in solution, we determine that the exciton transition dipole moments are anisotropic in strength. Our observations are consistent with a model in which splitting is driven by shape anisotropy in conjunction with long-range exchange.
Additional Information
© 2020 American Chemical Society. Received: December 28, 2019; Revised: January 18, 2020; Published: February 25, 2020. Published as part of The Journal of Physical Chemistry virtual special issue "Time-Resolved Microscopy". We thank Eran Rabani for valuable discussion. Nanowire synthesis and characterization were supported under the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract No. DE-AC02-05-CH11231, within the Physical Chemistry of Inorganic Nanostructures Program (KC3103). TA and TAM measurements were supported by the Center for Computational Study of Excited State Phenomena in Energy Materials (C2SEPEM), which is funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract No. DE-AC02-05CH11231, as part of the Computational Materials Sciences Program. stroboSCAT measurements were supported by the "Photonics at Thermodynamic Limits" Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, under Award DE-SC0019140. Theoretical calculations of exciton fine structure, long-range exchange interaction, and polarization memory effect were supported as part of the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE), an Energy Frontier Research Center funded by the Office of Basic Energy Sciences, Office of Science within the U.S. Department of Energy. J.L.L., N.B., and A.L.E. also acknowledge support from the U.S. Office of Naval Research through the U.S. Naval Research Laboratory's core research program. The work of A.L.E. and J.L.L. was supported by the Laboratory-University Collaboration Initiative of the DoD Basic Research Office. B.D.F. acknowledges a National Science Foundation Graduate Research Fellowship (DGE 1106400). N.S.G. acknowledges an Alfred P. Sloan Research Fellowship, a David and Lucile Packard Foundation Fellowship for Science and Engineering, and a Camille and Henry Dreyfus Teacher-Scholar Award. The authors declare no competing financial interest.Additional details
- Eprint ID
- 101550
- DOI
- 10.1021/acs.jpca.9b11981
- Resolver ID
- CaltechAUTHORS:20200225-135943971
- DE-AC02-05-CH11231
- Department of Energy (DOE)
- DE-SC0019140
- Department of Energy (DOE)
- Naval Research Laboratory
- Department of Defense
- DGE-1106400
- NSF Graduate Research Fellowship
- Alfred P. Sloan Foundation
- David and Lucile Packard Foundation
- Camille and Henry Dreyfus Foundation
- Created
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2020-02-26Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field