Browsing by Author "Kovalska, Evgeniya"

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    2D material liquid crystals for optoelectronics and photonics
    (Royal Society of Chemistry, 2017) Hogan, Ben T.; Kovalska, Evgeniya; Craciun, Monica F.; Baldycheva, Anna
    The merging of the materials science paradigms of liquid crystals and 2D materials promises superb new opportunities for the advancement of the fields of optoelectronics and photonics. In this review, we summarise the development of 2D material liquid crystals by two different methods: dispersion of 2D materials in a liquid crystalline host and the liquid crystal phase arising from dispersions of 2D material flakes in organic solvents. The properties of liquid crystal phases that make them attractive for optoelectronics and photonics applications are discussed. The processing of 2D materials to allow for the development of 2D material liquid crystals is also considered. An emphasis is placed on the applications of such materials; from the development of films, fibers and membranes to display applications, optoelectronic devices and quality control of synthetic processes. © 2017 The Royal Society of Chemistry.
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    Multispectral graphene-based electro-optical surfaces with reversible tunability from visible to microwave wavelengths
    (Nature Publishing Group, 2021-04-05) Ergoktas, M. S.; Bakan, G.; Kovalska, Evgeniya; Le Fevre, L. W.; Fields, R. P.; Steiner, P.; Yu, X.; Salihoğlu, Ömer; Balcı, S.; Fal’ko, V. I.; Novoselov, K. S.; Dryfe, R. A. W.; Kocabas, C.
    Optical materials with colour changing abilities have been explored for use in display devices1, smart windows2,3 or in the modulation of visual appearance4,5,6. The efficiency of these materials, however, has strong wavelength dependence, which limits their functionality to a specific spectral range. Here, we report graphene-based electro-optical devices with unprecedented optical tunability covering the entire electromagnetic spectrum from the visible to microwave. We achieve this non-volatile and reversible tunability by electro-intercalation of lithium into graphene layers in an optically accessible device structure. The unique colour changing capability, together with area-selective intercalation, inspires the fabrication of new multispectral devices, including display devices and electro-optical camouflage coating. We anticipate that these results provide realistic approaches for programmable smart optical surfaces with a potential utility in many scientific and engineering fields such as active plasmonics and adaptive thermal management.