Light-emitting properties in liquid-crystal (LC) electrochemiluminescent (ECL) cells doped with an organic
fluorescent dye (rubrene) were investigated. LC-ECL cells function based on the collision (recombination) of
oppositely charged radical ions (anions and cations), which move by an external electric field applied across
the cell. In this work, to obtain large values of luminance and current, a heating stir process was introduced in
a preparation procedure of rubrene-doped LC. It was found that the heating stir process dramatically
improves both of the luminance and current. It is considered that the drastic increase of the luminance and
current density is caused by the increase of the actual dye concentration. Next, to obtain polarized emission
based on the orientational nature of the nematic LC, emission properties of an LC-ECL cell with an
interdigitated electrode were investigated. As a result, the polarized emission from orientating dyes was
confirmed although its polarization ratio was not so high.
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