{"id":3941,"date":"2026-05-14T16:28:48","date_gmt":"2026-05-14T14:28:48","guid":{"rendered":"https:\/\/websrv.saske.sk\/uef\/en\/?p=3941"},"modified":"2026-05-14T16:28:48","modified_gmt":"2026-05-14T14:28:48","slug":"critical-dopant-concentration-enables-tunable-control-of-liquid-crystal-helices-for-energy-efficient-technologies","status":"publish","type":"post","link":"https:\/\/websrv.saske.sk\/uef\/en\/critical-dopant-concentration-enables-tunable-control-of-liquid-crystal-helices-for-energy-efficient-technologies\/","title":{"rendered":"Critical dopant concentration enables tunable control of liquid crystal helices for energy- efficient technologies"},"content":{"rendered":"

Liquid crystals are an integral part of modern technology, ranging from displays to advanced sensory systems. In a new study published in Scientific Reports<\/em><\/a>, researchers from the Institute of Experimental Physics of the Slovak Academy of Sciences (IEP SAS) in Ko\u0161ice, in collaboration with international partners, have demonstrated how minute changes in material composition can achieve precise control over behavior in electric and magnetic fields.<\/p>\n

The research focused on cholesteric liquid crystals, which naturally form spiral (helical) structures. These structures provide unique optical properties used in displays, smart windows, and virtual reality devices.<\/p>\n

The team investigated how the addition of a specific substance, a chiral dopant, affects the “unwinding” process of this helix. A key finding was the identification of a critical dopant concentration (approximately 0.6 vol.%), below which the helical structure does not form at all in thin layers. This occurs due to a competition between the material’s natural tendency to form a helical arrangement and the surface anchoring of molecules on the glass plates, which forces them into a perpendicular orientation. Only after exceeding this threshold do unique properties appear, such as discrete structural jumps and significant hysteresis.<\/p>\n

Using capacitance measurements, the researchers monitored the transition between the cholesteric and nematic phases as voltage was gradually increased. The electric field progressively unwinds the helical structure and aligns the molecules in the direction of the field. The study showed that the critical voltage required for this transition increases with higher dopant concentrations, as a tighter helix can only be unwound by a stronger field. At higher dopant concentrations, the scientists also observed pitch jumps (discontinuous changes in the helix rotation) indicating the existence of multiple stable states within the material.<\/p>\n

Similar behavior was observed in magnetic fields. When the field is gradually reduced, the system does not immediately return to its original state. Instead, it exhibits hysteresis- a range of field strengths where two stable optical states can coexist. This phenomenon is crucial for technologies requiring bistability or multistability.<\/p>\n

“Our results show that the concentration of the chiral additive, combined with the cell geometry, determines whether the cholesteric structure unwinds smoothly or in steps, and what field strength is required for this transition,” explains Veronika Lackov\u00e1<\/strong>, the study\u00b4s lead author. “These findings are particularly important for the design of responsive cholesteric materials and for future electro- and magneto-optical applications, where a precise and repeatable change of optical state is desired with minimal energy consumption.”<\/p>\n

The study also establishes a foundation for future research into more complex hybrid systems, including the combination of these liquid crystals with magnetic nanoparticles. These hybrid systems could offer an even more sensitive response to external stimuli, opening doors to innovations in photonics and imaging technologies.<\/p>\n

Author:<\/strong> Veronika Lackov\u00e1, Institute of Experimental Physics of the Slovak Academy of Sciences (IEP SAS)<\/p>\n","protected":false},"excerpt":{"rendered":"

Liquid crystals are an integral part of modern technology, ranging from displays to advanced sensory systems. In a new study published in Scientific Reports, researchers…<\/p>\n","protected":false},"author":11,"featured_media":3942,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-3941","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/posts\/3941","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/comments?post=3941"}],"version-history":[{"count":1,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/posts\/3941\/revisions"}],"predecessor-version":[{"id":3943,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/posts\/3941\/revisions\/3943"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/media\/3942"}],"wp:attachment":[{"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/media?parent=3941"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/categories?post=3941"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/tags?post=3941"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}