TY - JOUR
T1 - Substituent effects on singlet exciton fission in polycrystalline thin films of Cyano-substituted diaryltetracenes
AU - Margulies, Eric A.
AU - Kerisit, Nicolas
AU - Gawel, Przemyslaw
AU - Mauck, Catherine M.
AU - Ma, Lin
AU - Miller, Claire E.
AU - Young, Ryan M.
AU - Trapp, Nils
AU - Wu, Yi Lin
AU - Diederich, Francois
AU - Wasielewski, Michael R.
N1 - Funding Information:
This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, U.S. Department of Energy (DOE), under Grant No. DE-FG02-99ER14999 (M.R.W.) and the Swiss National Science Foundation (SNF 200020_159802). This work made use of the J. B. Cohen X-ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-1121262) at the Materials Research Center of North-western University and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205), as well as the Keck-II facility of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN.
PY - 2017/10/5
Y1 - 2017/10/5
N2 - Cyano-substituted tetracenes (5,11-dicyano-6,12-diphenyltetracene, Tet) undergo exoergic singlet fission (SF), a spin-allowed photophysical process that generates a pair of triplet excitons from one singlet exciton. To elucidate substituent effects on SF, we have measured the SF dynamics and triplet yields of thin films, formed by Tet bearing hydrogen (H), methyl (Me), fluoro (F), and trimethylsilyl (TMS) substituents on the p-phenyl positions and on the 3 and 9 positions of the tetracene core, by time-resolved spectroscopy in the vis-NIR and IR regions. The H-, Me-, and F-Tet display strong intramolecular electronic coupling (π-π distances <4 Å), and SF gives high triplet exciton yields up to 200% (quantitative). In addition, a charge-transfer state mediates SF in F-Tet films, while H-Tet and Me-Tet show no evidence for such a state. Correlations between the SF yields and the crystal structure show that chromophore slippage along both their short and long axes allows efficient SF and that a large degree of π contact between the chromophores is not necessary for rapid and efficient SF in the solid state. As expected, the large interchromophore distance in TMS-Tet (>4 Å) reduces its SF triplet yield to about 60%.
AB - Cyano-substituted tetracenes (5,11-dicyano-6,12-diphenyltetracene, Tet) undergo exoergic singlet fission (SF), a spin-allowed photophysical process that generates a pair of triplet excitons from one singlet exciton. To elucidate substituent effects on SF, we have measured the SF dynamics and triplet yields of thin films, formed by Tet bearing hydrogen (H), methyl (Me), fluoro (F), and trimethylsilyl (TMS) substituents on the p-phenyl positions and on the 3 and 9 positions of the tetracene core, by time-resolved spectroscopy in the vis-NIR and IR regions. The H-, Me-, and F-Tet display strong intramolecular electronic coupling (π-π distances <4 Å), and SF gives high triplet exciton yields up to 200% (quantitative). In addition, a charge-transfer state mediates SF in F-Tet films, while H-Tet and Me-Tet show no evidence for such a state. Correlations between the SF yields and the crystal structure show that chromophore slippage along both their short and long axes allows efficient SF and that a large degree of π contact between the chromophores is not necessary for rapid and efficient SF in the solid state. As expected, the large interchromophore distance in TMS-Tet (>4 Å) reduces its SF triplet yield to about 60%.
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U2 - 10.1021/acs.jpcc.7b07870
DO - 10.1021/acs.jpcc.7b07870
M3 - Article
AN - SCOPUS:85032841270
VL - 121
SP - 21262
EP - 21271
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 39
ER -