Ionic Interface-effects in Electro-optical LC-cells

The work discusses ionic electrode processes in LC-cells driven by voltage. Ions in LC-material are generated by dissociation of residual impurities or (dye) additives, but by ageing of LC-material as well. Therefore even in carefully purified electro-optical cells temporal decomposition of the base material causes slow, but permanent increase of ion concentration. It is apparently manifesting in non-linear electrical response of LC-cell in the case of quick switching by pulse driving. Every change of voltage on cell electrodes induces re-charging process and causes flow of the space-charge limited current across LC-layer. Existence of the ions influences electro-optical performance of LC-cell. The ionic flow changes field distribution in LC-layer and can temporary distort molecular ordering. Ionic processes may superimpose an undesired intrusion on optical switching response of LC-cell and may result either in faster or in slower switching, depending on driving source parameters. In this paper we propose...