TY - JOUR
T1 - Two-Dimensional Electronic Spectroscopy Reveals Excitation Energy-Dependent State Mixing during Singlet Fission in a Terrylenediimide Dimer
AU - Mandal, Aritra
AU - Chen, Michelle
AU - Foszcz, Eileen D.
AU - Schultz, Jonathan D.
AU - Kearns, Nicholas M.
AU - Young, Ryan M.
AU - Zanni, Martin T.
AU - Wasielewski, Michael R.
N1 - Funding Information:
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DE-FG02-99ER14999 (M.R.W., synthesis, data acquisition and analysis) and by the National Science Foundation under Grant CHE-1665110 (M.T.Z. instrument design and data analysis). M.C. gratefully acknowledges support from the Ryan Fellowship and the Northwestern University International Institute for Nanotechnology.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/12/26
Y1 - 2018/12/26
N2 - Singlet fission (SF) is a spin-allowed process in which a singlet exciton, 1 (S 1 S 0 ), within an assembly of two or more chromophores spontaneously down-converts into two triplet excitons via a multiexciton correlated triplet pair state, 1 (T 1 T 1 ). To elucidate the involvement of charge transfer (CT) states and vibronic coupling in SF, we performed 2D electronic spectroscopy (2DES) on dilute solutions of a covalently linked, slip-stacked terrylene-3,4:11,12-bis(dicarboximide) (TDI) dimer. This dimer undergoes efficient SF in nonpolar 1,4-dioxane and symmetry-breaking charge separation in polar dichloromethane. The various 2DES spectral features in 1,4-dioxane show different pump wavelength dependencies, supporting the presence of mixed states with variable 1 (S 1 S 0 ), 1 (T 1 T 1 ) and CT contributions that evolve with time. Analysis of the 2DES spectra in dichloromethane reveals the presence of a state having largely 1 (T 1 T 1 ) character during charge separation. Therefore, the 1 (T 1 T 1 ) multiexciton state plays an important role in the photophysics of this TDI dimer irrespective of solvent polarity.
AB - Singlet fission (SF) is a spin-allowed process in which a singlet exciton, 1 (S 1 S 0 ), within an assembly of two or more chromophores spontaneously down-converts into two triplet excitons via a multiexciton correlated triplet pair state, 1 (T 1 T 1 ). To elucidate the involvement of charge transfer (CT) states and vibronic coupling in SF, we performed 2D electronic spectroscopy (2DES) on dilute solutions of a covalently linked, slip-stacked terrylene-3,4:11,12-bis(dicarboximide) (TDI) dimer. This dimer undergoes efficient SF in nonpolar 1,4-dioxane and symmetry-breaking charge separation in polar dichloromethane. The various 2DES spectral features in 1,4-dioxane show different pump wavelength dependencies, supporting the presence of mixed states with variable 1 (S 1 S 0 ), 1 (T 1 T 1 ) and CT contributions that evolve with time. Analysis of the 2DES spectra in dichloromethane reveals the presence of a state having largely 1 (T 1 T 1 ) character during charge separation. Therefore, the 1 (T 1 T 1 ) multiexciton state plays an important role in the photophysics of this TDI dimer irrespective of solvent polarity.
UR - http://www.scopus.com/inward/record.url?scp=85058860384&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85058860384&partnerID=8YFLogxK
U2 - 10.1021/jacs.8b08627
DO - 10.1021/jacs.8b08627
M3 - Article
C2 - 30501193
AN - SCOPUS:85058860384
VL - 140
SP - 17907
EP - 17914
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 51
ER -