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Real-time observation of multiexcitonic states in ultrafast singlet fission using coherent 2D electronic spectroscopy.

Bakulin, Artem A; Morgan, Sarah E; Kehoe, Tom B; Wilson, Mark W B; Chin, Alex W; Zigmantas, Donatas LU ; Egorova, Dassia and Rao, Akshay (2016) In Nature Chemistry 8(1). p.16-23
Abstract
Singlet fission is the spin-allowed conversion of a spin-singlet exciton into a pair of spin-triplet excitons residing on neighbouring molecules. To rationalize this phenomenon, a multiexcitonic spin-zero triplet-pair state has been hypothesized as an intermediate in singlet fission. However, the nature of the intermediate states and the underlying mechanism of ultrafast fission have not been elucidated experimentally. Here, we study a series of pentacene derivatives using ultrafast two-dimensional electronic spectroscopy and unravel the origin of the states involved in fission. Our data reveal the crucial role of vibrational degrees of freedom coupled to electronic excitations that facilitate the mixing of multiexcitonic states with... (More)
Singlet fission is the spin-allowed conversion of a spin-singlet exciton into a pair of spin-triplet excitons residing on neighbouring molecules. To rationalize this phenomenon, a multiexcitonic spin-zero triplet-pair state has been hypothesized as an intermediate in singlet fission. However, the nature of the intermediate states and the underlying mechanism of ultrafast fission have not been elucidated experimentally. Here, we study a series of pentacene derivatives using ultrafast two-dimensional electronic spectroscopy and unravel the origin of the states involved in fission. Our data reveal the crucial role of vibrational degrees of freedom coupled to electronic excitations that facilitate the mixing of multiexcitonic states with singlet excitons. The resulting manifold of vibronic states drives sub-100 fs fission with unity efficiency. Our results provide a framework for understanding singlet fission and show how the formation of vibronic manifolds with a high density of states facilitates fast and efficient electronic processes in molecular systems. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Nature Chemistry
volume
8
issue
1
pages
16 - 23
publisher
Nature Publishing Group
external identifiers
  • pmid:26673260
  • wos:000366675400007
  • scopus:84951035994
ISSN
1755-4330
DOI
10.1038/nchem.2371
language
English
LU publication?
yes
id
2a139cba-3b8f-40e3-b14f-81962389c1d6 (old id 8504611)
date added to LUP
2016-01-13 11:22:18
date last changed
2017-10-29 03:15:56
@article{2a139cba-3b8f-40e3-b14f-81962389c1d6,
  abstract     = {Singlet fission is the spin-allowed conversion of a spin-singlet exciton into a pair of spin-triplet excitons residing on neighbouring molecules. To rationalize this phenomenon, a multiexcitonic spin-zero triplet-pair state has been hypothesized as an intermediate in singlet fission. However, the nature of the intermediate states and the underlying mechanism of ultrafast fission have not been elucidated experimentally. Here, we study a series of pentacene derivatives using ultrafast two-dimensional electronic spectroscopy and unravel the origin of the states involved in fission. Our data reveal the crucial role of vibrational degrees of freedom coupled to electronic excitations that facilitate the mixing of multiexcitonic states with singlet excitons. The resulting manifold of vibronic states drives sub-100 fs fission with unity efficiency. Our results provide a framework for understanding singlet fission and show how the formation of vibronic manifolds with a high density of states facilitates fast and efficient electronic processes in molecular systems.},
  author       = {Bakulin, Artem A and Morgan, Sarah E and Kehoe, Tom B and Wilson, Mark W B and Chin, Alex W and Zigmantas, Donatas and Egorova, Dassia and Rao, Akshay},
  issn         = {1755-4330},
  language     = {eng},
  number       = {1},
  pages        = {16--23},
  publisher    = {Nature Publishing Group},
  series       = {Nature Chemistry},
  title        = {Real-time observation of multiexcitonic states in ultrafast singlet fission using coherent 2D electronic spectroscopy.},
  url          = {http://dx.doi.org/10.1038/nchem.2371},
  volume       = {8},
  year         = {2016},
}