Influence of Molecular Dynamics on the Dielectric Properties of Poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) -Based Devices


Autoria(s): Faria, G. C.; von Seggern, H.; Faria, Roberto Mendonça; Azevêdo, Eduardo Ribeiro de
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

05/11/2013

05/11/2013

2012

Resumo

This paper uses Nuclear Magnetic Resonance (NMR) and Differential Scanning Calorimetry (DSC) techniques to study the molecular relaxations and phase transitions in poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT), which has been extensively studied as the active thin film in organic devices. Besides the identification of the glass transition, beta relaxation and crystal-to-crystal phase transition, we correlate such phenomena with dielectric and transport mechanisms in diodes with F8BT as the active layer. The beta relaxation has been assigned to a transition at about 210 K measured by H-1 and C-13 solid state NMR, and can be attributed to local motions in the side chains. The glass transition has been detected by DSC and H-1 NMR. Dielectric spectroscopy (DS) carried out at low frequencies on diodes made from F8BT show two peaks which are coincident with the above transitions. This allowed us to correlate the electrical changes in the film with the onset of specific molecular motions. In addition, DS indicates a third peak related with a crystal-to-crystal phase transition. Finally, these transitions were correlated with changes in the carrier mobility recorded in thin films and published recently.

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2008/01935-5]

Deutscher Akademischer Austausch Dienst (DAAD) [A/09/72945, 415]

Deutscher Akademischer Austausch Dienst (DAAD)

FAPESP [2009/18354-8, 2007/08688-0]

FAPESP

CNPq

CNPq

MCT/INEO

MCT/INEO

Identificador

IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION, PISCATAWAY, v. 19, n. 4, supl. 1, Part 2, pp. 1181-1185, AUG, 2012

1070-9878

http://www.producao.usp.br/handle/BDPI/41347

10.1109/TDEI.2012.6259987

http://dx.doi.org/10.1109/TDEI.2012.6259987

Idioma(s)

eng

Publicador

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

PISCATAWAY

Relação

IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION

Direitos

restrictedAccess

Copyright IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Palavras-Chave #POLYMER #DIELECTRIC SPECTROSCOPY #MOLECULAR RELAXATION #F8BT #ORGANIC ELECTRONICS #CHARGE-TRANSPORT #CRYSTALLINE POLYMERS #RELAXATION PROCESSES #FILMS #MOBILITY #TRANSITION #ENGINEERING, ELECTRICAL & ELECTRONIC #PHYSICS, APPLIED
Tipo

article

original article

publishedVersion