title: Harvesting singlet fission for solar energy conversion via triplet energy transfer.
abstract: The efficiency of a conventional solar cell may be enhanced if one incorporates a molecular material capable of singlet fission, that is, the production of two triplet excitons from the absorption of a single photon. To implement this, we need to successfully harvest the two triplets from the singlet fission material. Here we show in the tetracene (Tc)/copper phthalocyanine (CuPc) model system that triplets produced from singlet fission in the former can transfer to the later on the timescale of 45±5 ps. However, the efficiency of triplet energy transfer is limited by a loss channel due to faster formation (400±100 fs) and recombination (2.6±0.5 ps) of charge transfer excitons at the interface. These findings suggest a design principle for efficient energy harvesting from singlet fission: one must reduce interfacial area between the two organic chromophores to minimize charge transfer/recombination while optimizing light absorption, singlet fission and triplet rather than singlet transfer.
authors.affiliation: 1] Texas Materials Institute, University of Texas, 102 E. 24th Street, Austin, Texas 78712, USA [2].
authors.forename: John R
authors.initials: JR
authors.lastname: Tritsch
authors.forename: Wai-Lun
authors.initials: WL
authors.lastname: Chan
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Wu
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Monahan
authors.forename: X-Y
authors.initials: XY
authors.lastname: Zhu