title: Direct Observation of a Charge-Transfer State Preceding High-Yield Singlet Fission in Terrylenediimide Thin Films.
abstract: Singlet exciton fission (SF) in organic chromophore assemblies results in the conversion of one singlet exciton (S1) into two triplet excitons (T1), provided that the overall process is exoergic, i.e., E(S1) > 2E(T1). We report on SF in thin polycrystalline films of two terrylene-3,4:11,12-bis(dicarboximide) (TDI) derivatives 1 and 2, which crystallize into two distinct π-stacked structures. Femtosecond transient absorption spectroscopy (fsTA) reveals a charge-transfer state preceding a 190% T1yield in films of 1, where the π-stacked TDI molecules are rotated by 23° along an axis perpendicular to their π systems. In contrast, when the TDI molecules are slip-stacked along their N-N axes in films of 2, fsTA shows excimer formation, followed by a 50% T1yield.
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Margulies
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Jenna L
authors.initials: JL
authors.lastname: Logsdon
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Miller
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Lin
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Ethan
authors.initials: E
authors.lastname: Simonoff
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Ryan M
authors.identifier: 0000-0002-5108-0261
authors.initials: RM
authors.lastname: Young
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: George C
authors.identifier: 0000-0001-5837-4740
authors.initials: GC
authors.lastname: Schatz
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Michael R
authors.identifier: 0000-0003-2920-5440
authors.initials: MR
authors.lastname: Wasielewski