Strong light–matter coupling to form exciton– and vibropolaritons is increasingly touted as a powerful tool to alter the fundamental properties of organic materials. It is proposed that these states and their facile tunability can be used to rewrite molecular potential energy landscapes and redirect photophysical pathways, with applications from catalysis to electronic devices. Crucial to their photophysical properties is the exchange of energy between coherent, bright polaritons and incoherent dark states. One of the most potent tools to explore this interplay is transient absorption/reflectance spectroscopy. Previous studies have revealed unexpectedly long lifetimes of the coherent polariton states, for which there is no theoretical explanation. Applying these transient methods to a series of strong-coupled organic microcavities, we recover similar long-lived spectral effects. Based on transfer-matrix modeling of the transient experiment, we find that virtually the entire photoresponse results from photoexcitation effects other than the generation of polariton states. Our results suggest that the complex optical properties of polaritonic systems make them especially prone to misleading optical signatures and that more challenging high-time-resolution measurements on high-quality microcavities are necessary to uniquely distinguish the coherent polariton dynamics.
REFERENCES
1.
D. J.
Tannor
and S. A.
Rice
, “Control of selectivity of chemical reaction via control of wave packet evolution
,” J. Chem. Phys.
83
(10
), 5013
–5018
(1985
).2.
P.
Brumer
and M.
Shapiro
, “Laser control of molecular processes
,” Annu. Rev. Phys. Chem.
43
(1
), 257
–282
(1992
).3.
W. S.
Warren
, H.
Rabitz
, and M.
Dahleh
, “Coherent control of quantum dynamics: The dream is alive
,” Science
259
(5101
), 1581
–1589
(1993
).4.
H.
Rabitz
, R.
De Vivie-Riedle
, M.
Motzkus
, and K.
Kompa
, “Whither the future of controlling quantum phenomena?
,” Science
288
, 824
–828
(2000
).5.
V. I.
Prokhorenko
, A. M.
Nagy
, and R. J. D.
Miller
, “Coherent control of the population transfer in complex solvated molecules at weak excitation. An experimental study
,” J. Chem. Phys.
122
(18
), 184502
(2005
).6.
V. I.
Prokhorenko
, A. M.
Nagy
, S. A.
Waschuk
, L. S.
Brown
, R. R.
Birge
, and R. J. D.
Miller
, “Coherent control of retinal isomerization in bacteriorhodopsin
,” Science
313
(5791
), 1257
–1261
(2006
).7.
J.
Holcman
, A.
Al Choueiry
, A.
Enderlin
, S.
Hameau
, T.
Barisien
, and L.
Legrand
, “Coherent control of the optical emission in a single organic quantum wire
,” Nano Lett.
11
(10
), 4496
–4502
(2011
).8.
M.
Delor
, P. A.
Scattergood
, I. V.
Sazanovich
, A. W.
Parker
, G. M.
Greetham
, A. J. H. M.
Meijer
, M.
Towrie
, and J. A.
Weinstein
, “Toward control of electron transfer in donor-acceptor molecules by bond-specific infrared excitation
,” Science
346
(6216
), 1492
–1495
(2014
).9.
M.
Liebel
and P.
Kukura
, “Lack of evidence for phase-only control of retinal photoisomerization in the strict one-photon limit
,” Nat. Chem.
9
, 45
–49
(2016
).10.
F.
Herrera
and F. C.
Spano
, “Cavity-controlled chemistry in molecular ensembles
,” Phys. Rev. Lett.
116
(23
), 238301
(2016
).11.
F.
Herrera
and F. C.
Spano
, “Dark vibronic polaritons and the spectroscopy of organic microcavities
,” Phys. Rev. Lett.
118
(22
), 223601
(2017
).12.
J.
Fregoni
, G.
Granucci
, M.
Persico
, and S.
Corni
, “Strong coupling with light enhances the photoisomerization quantum yield of azobenzene
,” Chem
6
(1
), 250
–265
(2020
).13.
J.
Flick
, M.
Ruggenthaler
, H.
Appel
, and A.
Rubio
, “Atoms and molecules in cavities, from weak to strong coupling in quantum-electrodynamics (QED) chemistry
,” Proc. Natl. Acad. Sci. U. S. A.
114
(12
), 3026
–3034
(2017
).14.
F.
Herrera
and F. C.
Spano
, “Absorption and photoluminescence in organic cavity QED
,” Phys. Rev. A
95
(5
), 053867
(2017
).15.
F.
Herrera
and F. C.
Spano
, “Theory of nanoscale organic cavities: The essential role of vibration-photon dressed states
,” ACS Photonics
5
(1
), 65
–79
(2018
).16.
R. F.
Ribeiro
, L. A.
Martínez-Martínez
, M.
Du
, J.
Campos-Gonzalez-Angulo
, and J.
Yuen-Zhou
, “Polariton chemistry: Controlling molecular dynamics with optical cavities
,” Chem. Sci.
9
(30
), 6325
–6339
(2018
).17.
J.
del Pino
, J.
Feist
, and F. J.
Garcia-Vidal
, “Quantum theory of collective strong coupling of molecular vibrations with a microcavity mode
,” New J. Phys.
17
(5
), 053040
(2015
).18.
C.
Gonzalez-Ballestero
, J.
Feist
, E.
Gonzalo Badía
, E.
Moreno
, and F. J.
Garcia-Vidal
, “Uncoupled dark states can inherit polaritonic properties
,” Phys. Rev. Lett.
117
(15
), 156402
(2016
).19.
J. A.
Ćwik
, P.
Kirton
, S.
De Liberato
, and J.
Keeling
, “Excitonic spectral features in strongly coupled organic polaritons
,” Phys. Rev. A
93
(3
), 033840
(2016
).20.
M. A.
Zeb
, P. G.
Kirton
, and J.
Keeling
, “Exact states and spectra of vibrationally dressed polaritons
,” ACS Photonics
5
(1
), 249
–257
(2018
).21.
J.
Feist
, J.
Galego
, and F. J.
Garcia-Vidal
, “Polaritonic chemistry with organic molecules
,” ACS Photonics
5
(1
), 205
–216
(2018
).22.
J.
Galego
, F. J.
Garcia-Vidal
, and J.
Feist
, “Suppressing photochemical reactions with quantized light fields
,” Nat. Commun.
7
, 13841
(2016
).23.
J.
Galego
, F. J.
Garcia-Vidal
, and J.
Feist
, “Cavity-induced modifications of molecular structure in the strong coupling regime
,” Phys. Rev. X
5
, 041022
(2015
).24.
D. M.
Coles
, Y.
Yang
, Y.
Wang
, R. T.
Grant
, R. A.
Taylor
, S. K.
Saikin
, A.
Aspuru-Guzik
, D. G.
Lidzey
, J. K.-H.
Tang
, and J. M.
Smith
, “Strong coupling between chlorosomes of photosynthetic bacteria and a confined optical cavity mode
,” Nat. Commun.
5
, 5561
(2014
).25.
D.
Coles
, L. C.
Flatten
, T.
Sydney
, E.
Hounslow
, S. K.
Saikin
, A.
Aspuru‐Guzik
, V.
Vedral
, J. K. H.
Tang
, R. A.
Taylor
, J. M.
Smith
, and D. G.
Lidzey
, “A nanophotonic structure containing living photosynthetic bacteria
,” Small
13
(38
), 1701777
(2017
).26.
A.
Thomas
, L.
Lethuillier-Karl
, K.
Nagarajan
, R. M. A.
Vergauwe
, J.
George
, T.
Chervy
, A.
Shalabney
, E.
Devaux
, C.
Genet
, J.
Moran
, and T. W.
Ebbesen
, “Tilting a ground-state reactivity landscape by vibrational strong coupling
,” Science
363
(6427
), 615
–619
(2019
).27.
B.
Xiang
, R. F.
Ribeiro
, M.
Du
, L.
Chen
, Z.
Yang
, J.
Wang
, J.
Yuen-Zhou
, and W.
Xiong
, “Intermolecular vibrational energy transfer enabled by microcavity strong light–matter coupling
,” Science
368
(6491
), 665
–667
(2020
).28.
J. A.
Hutchison
, T.
Schwartz
, C.
Genet
, E.
Devaux
, and T. W.
Ebbesen
, “Modifying chemical landscapes by coupling to vacuum fields
,” Angew. Chem., Int. Ed.
51
(7
), 1592
–1596
(2012
).29.
R. M. A.
Vergauwe
, A.
Thomas
, K.
Nagarajan
, A.
Shalabney
, J.
George
, T.
Chervy
, M.
Seidel
, E.
Devaux
, V.
Torbeev
, and T. W.
Ebbesen
, “Modification of enzyme activity by vibrational strong coupling of water
,” Angew. Chem., Int. Ed.
58
(43
), 15324
–15328
(2019
).30.
E.
Orgiu
, J.
George
, J. A.
Hutchison
, E.
Devaux
, J. F.
Dayen
, B.
Doudin
, F.
Stellacci
, C.
Genet
, J.
Schachenmayer
, C.
Genes
, G.
Pupillo
, P.
Samorì
, and T. W.
Ebbesen
, “Conductivity in organic semiconductors hybridized with the vacuum field
,” Nat. Mater.
14
, 1123
–1130
(2015
).31.
D. M.
Coles
, N.
Somaschi
, P.
Michetti
, C.
Clark
, P. G.
Lagoudakis
, P. G.
Savvidis
, and D. G.
Lidzey
, “Polariton-mediated energy transfer between organic dyes in a strongly coupled optical microcavity
,” Nat. Mater.
13
(7
), 712
–719
(2014
).32.
X.
Zhong
, T.
Chervy
, L.
Zhang
, A.
Thomas
, J.
George
, C.
Genet
, J. A.
Hutchison
, and T. W.
Ebbesen
, “Energy transfer between spatially separated entangled molecules
,” Angew. Chem., Int. Ed.
56
(31
), 9034
–9038
(2017
).33.
K.
Georgiou
, P.
Michetti
, L.
Gai
, M.
Cavazzini
, Z.
Shen
, and D. G.
Lidzey
, “Control over energy transfer between fluorescent BODIPY dyes in a strongly coupled microcavity
,” ACS Photonics
5
(1
), 258
–266
(2018
).34.
K.
Stranius
, M.
Hertzog
, and K.
Börjesson
, “Selective manipulation of electronically excited states through strong light–matter interactions
,” Nat. Commun.
9
(1
), 2273
(2018
).35.
S.
Takahashi
, K.
Watanabe
, and Y.
Matsumoto
, “Singlet fission of amorphous rubrene modulated by polariton formation
,” J. Chem. Phys.
151
(7
), 074703
(2019
).36.
A. M.
Berghuis
, A.
Halpin
, Q.
Le‐Van
, M.
Ramezani
, S.
Wang
, S.
Murai
, and J.
Gómez Rivas
, “Enhanced delayed fluorescence in tetracene crystals by strong light‐matter coupling
,” Adv. Funct. Mater.
29
, 1901317
(2019
).37.
D.
Polak
, R.
Jayaprakash
, T. P.
Lyons
, L. Á.
Martínez-Martínez
, A.
Leventis
, K. J.
Fallon
, H.
Coulthard
, D. G.
Bossanyi
, K.
Georgiou
, A. J.
Petty
II, J.
Anthony
, H.
Bronstein
, J.
Yuen-Zhou
, A. I.
Tartakovskii
, J.
Clark
, and A. J.
Musser
, “Manipulating molecules with strong coupling: Harvesting triplet excitons in organic exciton microcavities
,” Chem. Sci.
11
(2
), 343
–354
(2020
).38.
D. G.
Lidzey
, D. D. C.
Bradley
, M. S.
Skolnick
, T.
Virgili
, S.
Walker
, and D. M.
Whittaker
, “Strong exciton-photon coupling in an organic semiconductor microcavity
,” Nature
395
, 53
–55
(1998
).39.
D. G.
Lidzey
, D. D. C.
Bradley
, T.
Virgili
, A.
Armitage
, M. S.
Skolnick
, and S.
Walker
, “Room temperature polariton emission from strongly coupled organic semiconductor microcavities
,” Phys. Rev. Lett.
82
(16
), 3316
(1999
).40.
D. M.
Coles
, R. T.
Grant
, D. G.
Lidzey
, C.
Clark
, and P. G.
Lagoudakis
, “Imaging the polariton relaxation bottleneck in strongly coupled organic semiconductor microcavities
,” Phys. Rev. B
88
, 121303
(2013
).41.
R. T.
Grant
, P.
Michetti
, A. J.
Musser
, P.
Gregoire
, T.
Virgili
, E.
Vella
, M.
Cavazzini
, K.
Georgiou
, F.
Galeotti
, C.
Clark
, J.
Clark
, C.
Silva
, and D. G.
Lidzey
, “Efficient radiative pumping of polaritons in a strongly coupled microcavity by a fluorescent molecular dye
,” Adv. Opt. Mater.
4
(10
), 1615
–1623
(2016
).42.
J. D.
Plumhof
, T.
Stöferle
, L.
Mai
, U.
Scherf
, and R. F.
Mahrt
, “Room-temperature Bose-Einstein condensation of cavity exciton-polaritons in a polymer
,” Nat. Mater.
13
(4
), 247
–252
(2014
).43.
A.
Graf
, M.
Held
, Y.
Zakharko
, L.
Tropf
, M. C.
Gather
, and J.
Zaumseil
, “Electrical pumping and tuning of exciton-polaritons in carbon nanotube microcavities
,” Nat. Mater.
16
(9
), 911
–917
(2017
).44.
A.
Graf
, L.
Tropf
, Y.
Zakharko
, J.
Zaumseil
, and M. C.
Gather
, “Near-infrared exciton-polaritons in strongly coupled single-walled carbon nanotube microcavities
,” Nat. Commun.
7
, 13078
(2016
).45.
D. M.
Coles
, P.
Michetti
, C.
Clark
, W. C.
Tsoi
, A. M.
Adawi
, J.-S.
Kim
, and D. G.
Lidzey
, “Vibrationally assisted polariton-relaxation processes in strongly coupled organic-semiconductor microcavities
,” Adv. Funct. Mater.
21
, 3691
–3696
(2011
).46.
J.
Keeling
and S.
Kéna-Cohen
, “Bose–Einstein condensation of exciton-polaritons in organic microcavities
,” Annu. Rev. Phys. Chem.
71
(1
), 435
–459
(2020
).47.
V. M.
Agranovich
, M.
Litinskaia
, and D. G.
Lidzey
, “Cavity polaritons in microcavities containing disordered organic semiconductors
,” Phys. Rev. B
67
, 085311
(2003
).48.
M.
Litinskaya
, P.
Reineker
, and V. M.
Agranovich
, “Fast polariton relaxation in strongly coupled organic microcavities
,” J. Lumin.
110
(4
), 364
–372
(2004
).49.
T.
Virgili
, D.
Coles
, A. M.
Adawi
, C.
Clark
, P.
Michetti
, S. K.
Rajendran
, D.
Brida
, D.
Polli
, G.
Cerullo
, and D. G.
Lidzey
, “Ultrafast polariton relaxation dynamics in an organic semiconductor microcavity
,” Phys. Rev. B
83
, 245309
(2011
).50.
T.
Schwartz
, J. A.
Hutchison
, J.
Léonard
, C.
Genet
, S.
Haacke
, and T. W.
Ebbesen
, “Polariton dynamics under strong light-molecule coupling
,” ChemPhysChem
14
(1
), 125
–131
(2013
).51.
C. A.
Delpo
, B.
Kudisch
, K. H.
Park
, S.-U.-Z.
Khan
, F.
Fassioli
, D.
Fausti
, B. P.
Rand
, and G. D.
Scholes
, “Polariton transitions in femtosecond transient absorption studies of ultrastrong light-molecule coupling
,” J. Phys. Chem. Lett.
11
(7
), 2667
–2674
(2020
).52.
A. G.
Avramenko
and A. S.
Rury
, “Quantum control of ultrafast internal conversion using nanoconfined virtual photons
,” J. Phys. Chem. Lett.
11
(3
), 1013
–1021
(2020
).53.
G. G.
Rozenman
, K.
Akulov
, A.
Golombek
, and T.
Schwartz
, “Long-range transport of organic exciton-polaritons revealed by ultrafast microscopy
,” ACS Photonics
5
(1
), 105
–110
(2018
).54.
L.
Mewes
, M.
Wang
, R. A.
Ingle
, K.
Börjesson
, and M.
Chergui
, “Energy relaxation pathways between light-matter states revealed by coherent two-dimensional spectroscopy
,” Commun. Phys.
3
(1
), 157
(2020
).55.
X.
Zhong
, T.
Chervy
, S.
Wang
, J.
George
, A.
Thomas
, J. A.
Hutchison
, E.
Devaux
, C.
Genet
, and T. W.
Ebbesen
, “Non-radiative energy transfer mediated by hybrid light-matter states
,” Angew. Chem., Int. Ed.
55
, 6202
–6206
(2016
).56.
A. D.
Dunkelberger
, B. T.
Spann
, K. P.
Fears
, B. S.
Simpkins
, and J. C.
Owrutsky
, “Modified relaxation dynamics and coherent energy exchange in coupled vibration-cavity polaritons
,” Nat. Commun.
7
, 13504
(2016
).57.
A. D.
Dunkelberger
, R. B.
Davidson
, W.
Ahn
, B. S.
Simpkins
, and J. C.
Owrutsky
, “Ultrafast transmission modulation and recovery via vibrational strong coupling
,” J. Phys. Chem. A
122
(4
), 965
–971
(2018
).58.
B.
Xiang
, R. F.
Ribeiro
, L.
Chen
, J.
Wang
, M.
Du
, J.
Yuen-Zhou
, and W.
Xiong
, “State-selective polariton to dark state relaxation dynamics
,” J. Phys. Chem. A
123
(28
), 5918
–5927
(2019
).59.
B.
Xiang
, R. F.
Ribeiro
, Y.
Li
, A. D.
Dunkelberger
, B. B.
Simpkins
, J.
Yuen-Zhou
, and W.
Xiong
, “Manipulating optical nonlinearities of molecular polaritons by delocalization
,” Sci. Adv.
5
(9
), eaax5196
(2019
).60.
T.
Yagafarov
, D.
Sannikov
, A.
Zasedatelev
, K.
Georgiou
, A.
Baranikov
, O.
Kyriienko
, I.
Shelykh
, L.
Gai
, Z.
Shen
, D.
Lidzey
, and P.
Lagoudakis
, “Mechanisms of blueshifts in organic polariton condensates
,” Commun. Phys.
3
(1
), 18
(2020
).61.
B.
Liu
, V. M.
Menon
, and M. Y.
Sfeir
, “The role of long-lived excitons in the dynamics of strongly coupled molecular polaritons
,” ACS Photonics
7
(8
), 2292
–2301
(2020
).62.
B.
Liu
, V. M.
Menon
, and M. Y.
Sfeir
, “Ultrafast thermal modification of strong coupling in an organic microcavity
,” APL Photonics
6
(1
), 016103
(2021
).63.
Z.
Wang
, Y.
Xie
, K.
Xu
, J.
Zhao
, and K. D.
Glusac
, “Diiodobodipy-styrylbodipy dyads: Preparation and study of the intersystem crossing and fluorescence resonance energy transfer
,” J. Phys. Chem. A
119
(26
), 6791
–6806
(2015
).64.
R. T.
Grant
, R.
Jayaprakash
, D. M.
Coles
, A.
Musser
, S.
De Liberato
, I. D. W.
Samuel
, G. A.
Turnbull
, J.
Clark
, and D. G.
Lidzey
, “Strong coupling in a microcavity containing β-carotene
,” Opt. Express
26
(3
), 3320
(2018
).65.
S. A.
Furman
and A. V.
Tikhonravov
, “Spectral characteristics of multilayer coatings: Theory
,” in Basics of Optics of Multilayer Systems
(Atlantica Séguier Frontières
, Paris
, 1992
), pp. 1
–102
.66.
M.
Liebel
, C.
Schnedermann
, and P.
Kukura
, “Sub-10-fs pulses tunable from 480 to 980 nm from a NOPA pumped by an Yb:KGW source
,” Opt. Lett.
39
(14
), 4112
(2014
).67.
A. J.
Musser
, S. K.
Rajendran
, K.
Georgiou
, L.
Gai
, R. T.
Grant
, Z.
Shen
, M.
Cavazzini
, A.
Ruseckas
, G. A.
Turnbull
, I. D. W.
Samuel
, J.
Clark
, and D. G.
Lidzey
, “Intermolecular states in organic dye dispersions: Excimers vs. aggregates
,” J. Mater. Chem. C
5
(33
), 8380
–8389
(2017
).68.
K.
Georgiou
, R.
Jayaprakash
, A.
Askitopoulos
, D. M.
Coles
, P. G.
Lagoudakis
, and D. G.
Lidzey
, “Generation of anti-Stokes fluorescence in a strongly coupled organic semiconductor microcavity
,” ACS Photonics
5
(11
), 4343
–4351
(2018
).69.
T.
Cookson
, K.
Georgiou
, A.
Zasedatelev
, R. T.
Grant
, T.
Virgili
, M.
Cavazzini
, F.
Galeotti
, C.
Clark
, N. G.
Berloff
, D. G.
Lidzey
, and P. G.
Lagoudakis
, “A yellow polariton condensate in a dye filled microcavity
,” Adv. Opt. Mater.
5
(18
), 1700203
(2017
).70.
C.
Schäfer
, J.
Mony
, T.
Olsson
, and K.
Börjesson
, “Entropic mixing allows monomeric-like absorption in neat BODIPY films
,” Chem. -Eur. J.
26
(63
), 14295
–14299
(2020
).71.
D.
Sannikov
, T.
Yagafarov
, K.
Georgiou
, A.
Zasedatelev
, A.
Baranikov
, L.
Gai
, Z.
Shen
, D. G.
Lidzey
, and P.
Lagoudakis
, “Room temperature broadband polariton lasing from a dye-filled microcavity
,” Adv. Opt. Mater.
7
(17
), 1900163
(2019
).72.
V.
Savona
, L. C.
Andreani
, P.
Schwendimann
, and A.
Quattropani
, “Quantum well excitons in semiconductor microcavities: Unified treatment of weak and strong coupling regimes
,” Solid State Commun.
93
(9
), 733
–739
(1995
).73.
R.
Montero
, V.
Martínez-Martínez
, A.
Longarte
, N.
Epelde-Elezcano
, E.
Palao
, I.
Lamas
, H.
Manzano
, A. R.
Agarrabeitia
, I.
López Arbeloa
, M. J.
Ortiz
, and I.
Garcia-Moreno
, “Singlet fission mediated photophysics of BODIPY dimers
,” J. Phys. Chem. Lett.
9
(3
), 641
–646
(2018
).74.
D. G.
Lidzey
and D. M.
Coles
, “Strong coupling in organic and hybrid-semiconductor microcavity structures
,” in Organic and Hybrid Photonic Crystals
(Springer International Publishing
, Cham
, 2015
), pp. 243
–273
.75.
B. I.
Afinogenov
, V. O.
Bessonov
, I. V.
Soboleva
, and A. A.
Fedyanin
, “Ultrafast all-optical light control with Tamm plasmons in photonic nanostructures
,” ACS Photonics
6
(4
), 844
–850
(2019
).76.
J.
Kuttruff
, D.
Garoli
, J.
Allerbeck
, R.
Krahne
, A.
De Luca
, D.
Brida
, V.
Caligiuri
, and N.
Maccaferri
, “Ultrafast all-optical switching enabled by epsilon-near-zero-tailored absorption in metal-insulator nanocavities
,” Commun. Phys.
3
(1
), 114
(2020
).77.
M.
Ramezani
, A.
Halpin
, S.
Wang
, M.
Berghuis
, and J. G.
Rivas
, “Ultrafast dynamics of nonequilibrium organic exciton-polariton condensates
,” Nano Lett.
19
(12
), 8590
–8596
(2019
).78.
G. S.
Kanner
, S.
Frolov
, and Z. V.
Vardeny
, “Photoinduced strain as a probe of acoustical and electronic properties of conducting polymers
,” Mod. Phys. Lett. B
09
(26n27
), 1701
–1717
(1995
).79.
J. K.
Cooper
, S. E.
Reyes-Lillo
, L. H.
Hess
, C.-M.
Jiang
, J. B.
Neaton
, and I. D.
Sharp
, “Physical origins of the transient absorption spectra and dynamics in thin-film semiconductors: The case of BiVO4
,” J. Phys. Chem. C
122
(36
), 20642
–20652
(2018
).80.
J.
Zhu
, X.
Wu
, D. M.
Lattery
, W.
Zheng
, and X.
Wang
, “The ultrafast laser pump-probe technique for thermal characterization of materials with micro/nanostructures
,” Nanoscale Microscale Thermophys. Eng.
21
(3
), 177
–198
(2017
).81.
E.
Olejnik
, B.
Pandit
, T.
Basel
, E.
Lafalce
, C.-X.
Sheng
, C.
Zhang
, X.
Jiang
, and Z. V.
Vardeny
, “Ultrafast optical studies of ordered poly(3-thienylene-vinylene) films
,” Phys. Rev. B
85
(23
), 235201
(2012
).82.
S.
Albert-Seifried
and R. H.
Friend
, “Measurement of thermal modulation of optical absorption in pump-probe spectroscopy of semiconducting polymers
,” Appl. Phys. Lett.
98
(22
), 223304
(2011
).83.
A.
Rao
, M. W. B.
Wilson
, S.
Albert-Seifried
, R.
Di Pietro
, and R. H.
Friend
, “Photophysics of pentacene thin films: The role of exciton fission and heating effects
,” Phys. Rev. B
84
(19
), 195411
(2011
).84.
A. K.
Le
, J. A.
Bender
, and S. T.
Roberts
, “Slow singlet fission observed in a polycrystalline perylenediimide thin film
,” J. Phys. Chem. Lett.
7
(23
), 4922
–4928
(2016
).© 2021 Author(s). Published under an exclusive license by AIP Publishing.
2021
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