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Description and importance of interchain excited states in conjugated polymer photophysics
Author(s) -
Jakubiak Rachel,
Yan Ming,
Wan Wai Chou,
Hsieh Bing R.,
Rothberg Lewis J.
Publication year - 2000
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/g4ue-elxc-5ldy-brx8
Subject(s) - photoexcitation , quantum yield , photoluminescence , chemistry , luminescence , stacking , excited state , polaron , polymer , conjugated system , photochemistry , yield (engineering) , optoelectronics , materials science , fluorescence , atomic physics , organic chemistry , optics , physics , quantum mechanics , metallurgy , electron
We compare the photoluminescence (PL) of poly‐ p ‐phenyl‐enevinylene (PPV) to that of one of its soluble derivatives, poly (2‐methoxy, 5‐(2 1 ‐ethylhexoxy)‐ p ‐phenylenevinylene) (MEH‐PPV). We show that excimers due to π‐orbital overlap of adjacent polymer backbones are formed in MEH‐PPV in high quantum yield. They do not emit light at room temperature, potentially explaining the reduction of PL yield in MEH‐PPV films relative to solution. The herringbone packing of polymer chains in PPV prevents π‐π stacking, but low PL yields are observed anyway. We conclude that polymer design to inhibit interchain registration is a questionable strategy to increase luminescence yields. The low PL yield in PPV is ascribed to bound polaron pair formation and preliminary data suggest that these may also form upon photoexcitation of MEH‐PPV films.