In-situ formation of polymer-stabilized/-free cholesteric bi-layer photonic crystal

IF 4.3 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Chemistry and Physics Pub Date : 2024-10-30 DOI:10.1016/j.matchemphys.2024.130093

Kuan-Wu Lin, Chun-Chuan Wang, Yu-Chieh Chang, Yu-Chieh Li, Chun-Ta Wang

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引用次数: 0

Abstract

Tunable photonic crystals based on cholesteric liquid crystals (CLCs) have attracted considerable attention due to their tunable optical properties and self-assembly capabilities. Despite the rapid development of various CLC-based devices, the narrow bandwidth of the photonic bandgap in CLCs limits their use in some practical applications. This paper presents a method for forming polymer-stabilized and polymer-free cholesteric bilayer photonic crystals in polymer-stabilized cholesteric liquid crystals (PSCLCs). By tuning the concentration of reactive monomers and controlling the UV polymerization conditions, two different PBGs can be formed within a single PSCLC cell. As the concentration of RM257 increases to 40 % and the intensity of UV light is used at 22 mW/cm², the distance between the two reflectance bands can reach 200 nm, reflecting green and red light. The dynamic formation process and the tunability of these cholesteric bilayer structures under electric fields and temperature variations are investigated. By controlling the temperature and electric field, the reflectance of the liquid crystal layer can be reduced from 50 % to 15 %, resulting in a single-band reflection. In addition, we have proposed a tunable polarization volume grating based on the cholesteric bi-layer photonic crystal, which can diffract two specific light colors.

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原位形成聚合物稳定/无胆固醇双层光子晶体

基于胆甾型液晶（CLC）的可调谐光子晶体因其可调谐的光学特性和自组装能力而备受关注。尽管各种基于胆甾型液晶的器件发展迅速，但胆甾型液晶的光子带隙带宽较窄，限制了它们在某些实际应用中的使用。本文介绍了一种在聚合物稳定胆固醇液晶（PSCLCs）中形成聚合物稳定和无聚合物胆固醇双层光子晶体的方法。通过调整反应性单体的浓度和控制紫外聚合条件，可以在单个 PSCLC 单元中形成两种不同的 PBG。当 RM257 的浓度增加到 40%、紫外光强度达到 22 mW/cm2 时，两条反射带之间的距离可达 200 nm，分别反射绿光和红光。研究了这些胆固醇双层结构在电场和温度变化下的动态形成过程和可调性。通过控制温度和电场，液晶层的反射率可从 50% 降低到 15%，从而实现单波段反射。此外，我们还提出了一种基于胆甾双层光子晶体的可调偏振体光栅，它可以衍射出两种特定的光色。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Materials Chemistry and Physics 工程技术-材料科学：综合

CiteScore

8.70

自引率

4.30%

发文量

1515

审稿时长

69 days

期刊介绍： Materials Chemistry and Physics is devoted to short communications, full-length research papers and feature articles on interrelationships among structure, properties, processing and performance of materials. The Editors welcome manuscripts on thin films, surface and interface science, materials degradation and reliability, metallurgy, semiconductors and optoelectronic materials, fine ceramics, magnetics, superconductors, specialty polymers, nano-materials and composite materials.