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Intrinsic femtosecond charge generation dynamics in single crystal CH3NH3PbI3

Valverde-Chavez, David A.; Ponseca, Carlito LU ; Stoumpos, Constantinos C.; Yartsev, Arkady LU ; Kanatzidis, Mercouri G.; Sundström, Villy LU and Cooke, David G. (2015) In Energy & Environmental Science 8(12). p.3700-3707
Abstract
Hybrid metal-organic perovskite solar cells have astounded the solar cell community with their rapid rise in efficiency while maintaining low-cost fabrication. The intrinsic material photophysics related to the generation of free charges, their dynamics and efficiency, however, remains to be understood. As fabrication techniques improve, larger crystal grain sizes have been shown to be a critical factor for improving both the optical and transport properties of the hybrid metal halide perovskites. In this work, we use pulses of multi-THz frequency light in the ultra-broadband 1-30 THz (4-125 meV) range to observe the ac conductivity in large single crystal CH3NH3PbI3. Our spectra reveal the ultrafast dynamics and efficiencies of free... (More)
Hybrid metal-organic perovskite solar cells have astounded the solar cell community with their rapid rise in efficiency while maintaining low-cost fabrication. The intrinsic material photophysics related to the generation of free charges, their dynamics and efficiency, however, remains to be understood. As fabrication techniques improve, larger crystal grain sizes have been shown to be a critical factor for improving both the optical and transport properties of the hybrid metal halide perovskites. In this work, we use pulses of multi-THz frequency light in the ultra-broadband 1-30 THz (4-125 meV) range to observe the ac conductivity in large single crystal CH3NH3PbI3. Our spectra reveal the ultrafast dynamics and efficiencies of free charge creation and extremely high charge carrier mobility as high as 500800 cm(2) V-1 s(-1). While quasi-equilibrium analysis of efficiencies through the Saha equation suggests a binding energy on the order of 49 meV, an observed reflectance feature appearing at high pump fluence occurs at 12 meV and is consistent with an orbital transition of the exciton, indicating a much lower Rydberg energy of 17 meV at room temperature. The signature of the exciton is found to vanish on a 1 ps time scale commensurate with the appearance of mobile carriers, consistent with thermal dissociation of the exciton to the continuum in the room temperature tetragonal phase. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Energy & Environmental Science
volume
8
issue
12
pages
3700 - 3707
publisher
Royal Society of Chemistry
external identifiers
  • wos:000365412300027
  • scopus:84948395832
ISSN
1754-5706
DOI
10.1039/c5ee02503f
language
English
LU publication?
yes
id
05a3e0f7-0ac6-4e34-9fcd-f05a19c0f17b (old id 8539846)
date added to LUP
2016-01-20 09:58:10
date last changed
2017-11-19 03:17:46
@article{05a3e0f7-0ac6-4e34-9fcd-f05a19c0f17b,
  abstract     = {Hybrid metal-organic perovskite solar cells have astounded the solar cell community with their rapid rise in efficiency while maintaining low-cost fabrication. The intrinsic material photophysics related to the generation of free charges, their dynamics and efficiency, however, remains to be understood. As fabrication techniques improve, larger crystal grain sizes have been shown to be a critical factor for improving both the optical and transport properties of the hybrid metal halide perovskites. In this work, we use pulses of multi-THz frequency light in the ultra-broadband 1-30 THz (4-125 meV) range to observe the ac conductivity in large single crystal CH3NH3PbI3. Our spectra reveal the ultrafast dynamics and efficiencies of free charge creation and extremely high charge carrier mobility as high as 500800 cm(2) V-1 s(-1). While quasi-equilibrium analysis of efficiencies through the Saha equation suggests a binding energy on the order of 49 meV, an observed reflectance feature appearing at high pump fluence occurs at 12 meV and is consistent with an orbital transition of the exciton, indicating a much lower Rydberg energy of 17 meV at room temperature. The signature of the exciton is found to vanish on a 1 ps time scale commensurate with the appearance of mobile carriers, consistent with thermal dissociation of the exciton to the continuum in the room temperature tetragonal phase.},
  author       = {Valverde-Chavez, David A. and Ponseca, Carlito and Stoumpos, Constantinos C. and Yartsev, Arkady and Kanatzidis, Mercouri G. and Sundström, Villy and Cooke, David G.},
  issn         = {1754-5706},
  language     = {eng},
  number       = {12},
  pages        = {3700--3707},
  publisher    = {Royal Society of Chemistry},
  series       = {Energy & Environmental Science},
  title        = {Intrinsic femtosecond charge generation dynamics in single crystal CH3NH3PbI3},
  url          = {http://dx.doi.org/10.1039/c5ee02503f},
  volume       = {8},
  year         = {2015},
}