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An in-situ neutron reflection measurement is developed that allows the direct relationship between film photoluminescence and structure to be studied. Understanding the effect of physical structure and the role of interfaces is critical for gaining insight into the optoelectronic properties of conjugated polymers.

The optomechanical characteristics of oriented polymer films made from a photopolymerizable liquid crystal diacrylate were examined, with general implications for oriented films of similar materials being used and considered for display-component applications. The results highlight the robustness of fully polymerized reactive mesogen optical films to withstand the moderate strains anticipated during manufacturing processes and in-service deformation caused by bending or impact.

Neutron reflection (NR) is used to study the physical structure of the light-emitting polymer poly[2-(2'-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene) (MEHPPV) films. The photoluminescence spectra of soluble MEHPPV before and after annealing showed that the densification observed in the NR measurements was mirrored in the emission properties of the polymer film and the thermal annealing of insoluble MEHPPV had little effect on the films physical structure.

We demonstrate a method for achieving polarized organic electroluminescence for liquid crystalline conjugated polymers that allows the polymer to be deposited directly onto the anode. The technique utilizes a top-down alignment approach whereby the predeposited polymer was aligned from above using a rubbed polyimide master and a smectic liquid crystal transfer layer. The liquid crystal/polyimide master bilayer was sandwiched with the liquid crystalline polymer that had been deposited onto the electrode. The sandwiched layers were then heated to achieve alignment before the removal of the polyimide master and liquid crystal transfer layer. Using this method, poly[2,7-{9,9-di(2-ethylhexyl)}fluorene] (PF2-6) was aligned to give an anisotropic polymer film. Light emitted from single layer light-emitting diodes containing the aligned PF2-6 had integrated dichroic ratios of up to 9.7. At 100 cd/m[sup 2], the single layer devices had external quantum and power efficiencies of 0.08% and 0.05 lm/W, respectively. Bilayer devices containing an electron transport layer between the PF2-6 and the cathode gave emitted light with good dichroic ratios and with the external quantum and power efficiencies at 100 cd/m[sup 2] being increased to 2.2% and 1.1 lm/W. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]