Nano Archive

Uniaxial alignment of liquid-crystalline conjugated polymers by nanoconfinement

Zheng, Zijian and Yim, Keng-Hoong and Saifullah, Mohammad S. M. and Welland, Mark E. and Friend, Richard H. and Kim, Ji-Seon and Huck, Wilhelm T. S. (2007) Uniaxial alignment of liquid-crystalline conjugated polymers by nanoconfinement. NANO LETTERS, 7 (4). pp. 987-992.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/nl070022k

Abstract

We demonstrate the uniaxial alignment of a liquid-crystalline conjugated polymer, poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) by means of nanoconfinement during nanoimprinting. The orientation of the conjugated backbones was parallel to the nanolines imprinted into the polymer film. Polarized UV-vis absorption and photoluminescence spectra were measured to quantify the degree of alignment, showing that the polarization ratio and uniaxial molecular order parameter were as high as 66 and 0.97, respectively. The aligned F8BT film was used as the active layer in a PLED, which resulted in polarized electroluminescence with a polarization ratio of 11. Ambipolar PFET in a top-gate configuration with aligned F8BT as the active semiconducting layer showed mobility enhancement when the chains were aligned parallel to the transport direction. Mobility anisotropies for hole and electron transport were 10-15 and 5-7, respectively, for current flow parallel and perpendicular to the alignment direction.

Item Type:Article
Subjects:Material Science > Functional and hybrid materials
Material Science > Nanofabrication processes and tools
ID Code:2461
Deposited By:Farnush Anwar
Deposited On:07 Jan 2009 12:57
Last Modified:09 Jan 2009 11:35

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