Intrachain Energy Migration to Weak Charge-Transfer State in Polyfluorene End-Capped with Naphthalimide Derivative
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
20/10/2012
20/10/2012
2010
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Resumo |
Polyfluorene end-capped with N-(2-benzothiazole)-1 8-naphthalimide (PF-BNI) is a highly fluorescent material with fluorescence emission modulated by solvent polarity Its low energy excited state is assigned as a mixed configuration state between the singlet S(1) of the fluorene backbone (F) with the charge transfer (CI) of the end group BNI The triexponential fluorescence decays of PF-BNI were associated with fast energy migration to form an intrachain charge-transfer (ICCT) state polyfluorene backbone decay and ICCT deactivation Time-resolved fluorescence anisotropy exhibited biexponential relaxation with a fast component of 12-16 ps in addition to a slow one in the range 0 8-1 4 ns depending on the solvent showing that depolarization occurs from two different processes energy migration to form the ICCT state and slow rotational diffusion motion of end segments at a longer time Results from femtosecond transient absorption measurements agreed with anisotropy decay and showed a decay component of about 16 ps at 605 nm in PF BNI ascribed to the conversion of S(1) to the ICCT excited state From the ratio of asymptotic and initial amplitudes of the transient absorption measurement the efficiency of intrachain ICCT formation is estimated in 0 5 which means that on average, half of the excited state formed in a BNI-(F)(n)-BNI chain with n = 32 is converted to its low energy intrachain charge-transfer (ICCT) state Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) FAPESP CNPq Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) CAPES Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) |
Identificador |
JOURNAL OF PHYSICAL CHEMISTRY A, v.114, n.47, p.12384-12390, 2010 1089-5639 http://producao.usp.br/handle/BDPI/31653 10.1021/jp108168f |
Idioma(s) |
eng |
Publicador |
AMER CHEMICAL SOC |
Relação |
Journal of Physical Chemistry A |
Direitos |
restrictedAccess Copyright AMER CHEMICAL SOC |
Palavras-Chave | #SUBSTITUTED 1,8-NAPHTHALIMIDE DERIVATIVES #CONJUGATED POLYMERS #EXCITED-STATE #PHOTOPHYSICAL BEHAVIOR #COPOLYMERS #DYE #FLUORENONE #DEPENDENCE #DYNAMICS #Chemistry, Physical #Physics, Atomic, Molecular & Chemical |
Tipo |
article original article publishedVersion |