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 polymeri...
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 a
slight 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.