title: A design strategy for intramolecular singlet fission mediated by charge-transfer states in donor-acceptor organic materials.
abstract: The ability to advance our understanding of multiple exciton generation (MEG) in organic materials has been restricted by the limited number of materials capable of singlet fission. A particular challenge is the development of materials that undergo efficient intramolecular fission, such that local order and strong nearest-neighbour coupling is no longer a design constraint. Here we address these challenges by demonstrating that strong intrachain donor-acceptor interactions are a key design feature for organic materials capable of intramolecular singlet fission. By conjugating strong-acceptor and strong-donor building blocks, small molecules and polymers with charge-transfer states that mediate population transfer between singlet excitons and triplet excitons are synthesized. Using transient optical techniques, we show that triplet populations can be generated with yields up to 170%. These guidelines are widely applicable to similar families of polymers and small molecules, and can lead to the development of new fission-capable materials with tunable electronic structure, as well as a deeper fundamental understanding of MEG.
authors.affiliation: 1] Energy Frontier Research Center, Columbia University, New York, New York 10027, USA [2] Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Busby
authors.affiliation: 1] Energy Frontier Research Center, Columbia University, New York, New York 10027, USA [2] Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: Jianlong
authors.initials: J
authors.lastname: Xia
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: Jonathan Z
authors.initials: JZ
authors.lastname: Low
authors.affiliation: Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Song
authors.affiliation: Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Miller
authors.affiliation: 1] Energy Frontier Research Center, Columbia University, New York, New York 10027, USA [2] Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: X-Y
authors.initials: XY
authors.lastname: Zhu
authors.affiliation: 1] Energy Frontier Research Center, Columbia University, New York, New York 10027, USA [2] Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Campos
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Matthew Y
authors.initials: MY
authors.lastname: Sfeir