Abstract
Methylammonium lead iodide (CH3NH3PbI3) hybrid perovskite in the tetragonal and orthorhombic phases have different exciton binding energies and demonstrate different excitation kinetics. Here, we explore the role that crystal structure plays in the kinetics via fluence dependent transient absorption spectroscopy. We observe stronger saturation of the free carrier concentration under high pump energy density in the orthorhombic phase relative to the tetragonal phase. We attribute this phenomenon to small dielectric constant, large exciton binding energy, and weak Coulomb screening, which results in difficult exciton dissociation under high light intensity in the orthorhombic phase. At higher excitation intensities, we observe a coherent phonon with an oscillation frequency of 23.4 cm-1 at 77 K, whose amplitude tracks the increase of the first-order lifetime.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3284-3289 |
| Number of pages | 6 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 7 |
| Issue number | 16 |
| DOIs | |
| State | Published - Aug 18 2016 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Materials Science(all)
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Coulomb Screening and Coherent Phonon in Methylammonium Lead Iodide Perovskites. / Wang, He; Valkunas, Leonas; Cao, Thu; Whittaker-Brooks, Luisa; Fleming, Graham R.
In: Journal of Physical Chemistry Letters, Vol. 7, No. 16, 18.08.2016, p. 3284-3289.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Coulomb Screening and Coherent Phonon in Methylammonium Lead Iodide Perovskites
AU - Wang, He
AU - Valkunas, Leonas
AU - Cao, Thu
AU - Whittaker-Brooks, Luisa
AU - Fleming, Graham R.
PY - 2016/8/18
Y1 - 2016/8/18
N2 - Methylammonium lead iodide (CH3NH3PbI3) hybrid perovskite in the tetragonal and orthorhombic phases have different exciton binding energies and demonstrate different excitation kinetics. Here, we explore the role that crystal structure plays in the kinetics via fluence dependent transient absorption spectroscopy. We observe stronger saturation of the free carrier concentration under high pump energy density in the orthorhombic phase relative to the tetragonal phase. We attribute this phenomenon to small dielectric constant, large exciton binding energy, and weak Coulomb screening, which results in difficult exciton dissociation under high light intensity in the orthorhombic phase. At higher excitation intensities, we observe a coherent phonon with an oscillation frequency of 23.4 cm-1 at 77 K, whose amplitude tracks the increase of the first-order lifetime.
AB - Methylammonium lead iodide (CH3NH3PbI3) hybrid perovskite in the tetragonal and orthorhombic phases have different exciton binding energies and demonstrate different excitation kinetics. Here, we explore the role that crystal structure plays in the kinetics via fluence dependent transient absorption spectroscopy. We observe stronger saturation of the free carrier concentration under high pump energy density in the orthorhombic phase relative to the tetragonal phase. We attribute this phenomenon to small dielectric constant, large exciton binding energy, and weak Coulomb screening, which results in difficult exciton dissociation under high light intensity in the orthorhombic phase. At higher excitation intensities, we observe a coherent phonon with an oscillation frequency of 23.4 cm-1 at 77 K, whose amplitude tracks the increase of the first-order lifetime.
UR - http://www.scopus.com/inward/record.url?scp=84983354796&partnerID=8YFLogxK
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U2 - 10.1021/acs.jpclett.6b01425
DO - 10.1021/acs.jpclett.6b01425
M3 - Article
AN - SCOPUS:84983354796
VL - 7
SP - 3284
EP - 3289
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 16
ER -