Highly polarized light emission from uniaxially aligned thin films of biphenyl/thienothiophene co-oligomer

Polarized light emission has various potential uses in electro-optic applications such as providing backlighting for liquid crystal displays without a loss of brightness. This study examined the highly polarized light emission of a thienothiophene-based oligomer, 2,5-bis-(4-biphenylyl)-thieno[3,2-b]thiophene (BPTT), deposited on a friction-transferred polymer film. The BPTT film showed a high polarization ratio of more than 6 by alignment of the backbone of the molecule along the friction-transfer direction of the polymer chain. A strong correlation between the photoluminescent spectrum and the morphology of the film also was observed.