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Tuning the optoelectronic properties of polyfluorenes by copolymerisation with thiophene moieties
A series of alternating copolymers of the type A- alt-B, where A is 9,9-bis(2′-ethylhexyl)fluorene and B is a thiophene-based moiety, was synthesised via the palladium-catalysed Suzuki coupling. These copolymers were characterised by optical and electrochemical methods and used in the fabrication of...
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Published in: | Synthetic metals 2002-03, Vol.127 (1), p.251-254 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | A series of alternating copolymers of the type A-
alt-B, where A is 9,9-bis(2′-ethylhexyl)fluorene and B is a thiophene-based moiety, was synthesised via the palladium-catalysed Suzuki coupling. These copolymers were characterised by optical and electrochemical methods and used in the fabrication of light-emitting diodes. We find that upon increasing the conjugation length of the B moiety, from a thiophene unit to 2,5-bis(2′-vinyl thienyl)thiophene, the fluorescence quantum yields are reduced both in solution (from 51 to 11%) and in solid state. Both absorption and emission are red-shifted, with the solid state emission maximum increasing from 476
nm (green) to 600
nm (orange). When the B unit is changed from thiophene to thiophene-
S,
S-dioxide, there is a significant increase in both the ionisation potential and electron affinity, and a concurrent reduction of the solution fluorescence efficiency (down to 16%). These polymers appear promising materials for optoelectronic applications. |
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ISSN: | 0379-6779 1879-3290 |
DOI: | 10.1016/S0379-6779(01)00637-3 |