Excimer and Aggregate Formations in Poly(fluorene)s

ETRI Journal

关键词: OLED;    PLED;    polymer light emitting diode;    Poly(fluorene);   

Others  :  1184462
DOI  :  10.4218/etrij.02.0102.0001

【 摘 要 】

This paper investigates the absorption and emission changes in poly(di-n-hexylfluorene)s. We prepared the poly(di-n-hexylfluorene)s end capped with 2-bromofluorene, 2-bromo-9,9-di-n-hexylfluorene, and 9-bromoanthracene through Ni (0) mediated polymerization. In addition, we also synthesized a structurally distorted copolymer of 2,7-dibromo-9,9-di-n-hexylfluorene and 9,9-bis(4-bromophenyl) fluorene end capped with 2-bromofluorene through the same polymerization method. The absorption and emission changes of these polymers between before and after thermal annealing in a nitrogen atmosphere clarify the role of aggregate/excimer formation in poly(fluorene)s. The large absorption changes must be attributed to aggregate formation (ground state interaction), which causes only aslight red shift of the vibronically structured emission bands.We assign the additional long wavelength emission as an excimer band (excited state interaction), which is preferably formed at chain ends.

   

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