Analysis on nanoparticles induced alignment stability of dye doped liquid crystal at varying temperatures

In this paper, an analysis on the stability of zinc oxide (ZnO) nanoparticles (NPs) induced homeotropic alignment (HA) of dichroic dye doped nematic liquid crystal (NLC) at varying temperatures has been carried out. Three sample cells, namely conventional PI coated homeotropically aligned liquid crystal (HALC) (S1), NPs induced HALC (S2), and dye doped NPs induced HALC (S3) were prepared. Further, their morphological and electro-optical (E-O) characteristics were determined between temperature ranges from 20 °C to 60 °C. Findings illustrate that there are no observable textural changes in terms of background consistency, phase transitions, and uniformity in coloration across all the cells. Also, with increasing electric field, the liquid crystal (LC) molecules exhibit uniform switching behavior up to 60 °C, confirming that the performance of the HALC device remains unaffected under elevated thermal conditions. Comparatively, cell S1 shows larger threshold and operating voltages, whereas cell S3 exhibits the most thermally stable alignment with low threshold and operating voltages with highest contrast ratio (CR) at all temperatures. Thus, NPs induced dichroic dye doped HALC cells have potential to contribute to the development of thermally reliable LC based devices.