TY - JOUR
T1 - Site-selective measurement of coupled spin pairs in an organic semiconductor
AU - Bayliss, S. L.
AU - Weiss, L. R.
AU - Mitioglu, A.
AU - Galkowski, K.
AU - Yang, Z.
AU - Yunusova, K.
AU - Surrente, A.
AU - Thorley, K. J.
AU - Behrends, J.
AU - Bittl, R.
AU - Anthony, J. E.
AU - Rao, A.
AU - Friend, R. H.
AU - Plochocka, P.
AU - Christianen, P. C.M.
AU - Greenham, N. C.
AU - Chepelianskii, A. D.
N1 - Publisher Copyright:
© 2018 National Academy of Sciences. All Rights Reserved.
PY - 2018/5/15
Y1 - 2018/5/15
N2 - From organic electronics to biological systems, understanding the role of intermolecular interactions between spin pairs is a key challenge. Here we show how such pairs can be selectively addressed with combined spin and optical sensitivity. We demonstrate this for bound pairs of spin-triplet excitations formed by singlet fission, with direct applicability across a wide range of synthetic and biological systems. We show that the site sensitivity of exchange coupling allows distinct triplet pairs to be resonantly addressed at different magnetic fields, tuning them between optically bright singlet (S = 0) and dark triplet quintet (S = 1, 2) configurations: This induces narrow holes in a broad optical emission spectrum, uncovering exchange-specific luminescence. Using fields up to 60 T, we identify three distinct triplet-pair sites, with exchange couplings varying over an order of magnitude (0.3–5 meV), each with its own luminescence spectrum, coexisting in a single material. Our results reveal how site selectivity can be achieved for organic spin pairs in a broad range of systems.
AB - From organic electronics to biological systems, understanding the role of intermolecular interactions between spin pairs is a key challenge. Here we show how such pairs can be selectively addressed with combined spin and optical sensitivity. We demonstrate this for bound pairs of spin-triplet excitations formed by singlet fission, with direct applicability across a wide range of synthetic and biological systems. We show that the site sensitivity of exchange coupling allows distinct triplet pairs to be resonantly addressed at different magnetic fields, tuning them between optically bright singlet (S = 0) and dark triplet quintet (S = 1, 2) configurations: This induces narrow holes in a broad optical emission spectrum, uncovering exchange-specific luminescence. Using fields up to 60 T, we identify three distinct triplet-pair sites, with exchange couplings varying over an order of magnitude (0.3–5 meV), each with its own luminescence spectrum, coexisting in a single material. Our results reveal how site selectivity can be achieved for organic spin pairs in a broad range of systems.
KW - Exchange coupling
KW - Organic semiconductors
KW - Organic spintronics
KW - Singlet fission
KW - Triplet excitons
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U2 - 10.1073/pnas.1718868115
DO - 10.1073/pnas.1718868115
M3 - Article
C2 - 29720443
AN - SCOPUS:85046939536
SN - 0027-8424
VL - 115
SP - 5077
EP - 5082
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 20
ER -