Abstract

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Title:: The Research Progress of Cholesteric Liquid Crystals with Broad Reflection band

Author(s):: WANG Menga; SUN Jian; LI Kexuan; SHEN Wenbo; LI Chenyued; LAN ruochen; ZHANG lanying; YANG Huai; School of Mechanical Electronic and Information Engineering, China University of Mining and Technology-Beijing
College of Engineering, Peking University
Department of Applied Statistics and Science, Xijing University
School of Materials Science and Engineering, University of Science and Technology Beijing

Keywords:: liquid crystals; cholesteric phase; selective reflection; broad bandwidth; nonuniform pitch distribution

Abstract:: Cholesteric liquid crystal (ChLC) materials with broad reflection band are witnessing a significant surge in interest due to their unique optical properties and potential applications in areas such as reflective polarizerfree displays, light enhancement films, smart switchable windows, laser protection or IRstealth. In the decades, extensive investigations have been made on broadening the reflection bandwidth. And several effective methods and processing techniques have been developed. In summary, a variation of pitch (whether a pitch gradient or a random distribution in the volume of materials) is integral to obtain a ChLC with a broad reflection band. According to the broadening mechanisms, they are classified to be stacking method, light induced molecular diffusion method, thermal diffusion method, method of external stimuliinduced variation in concentration or helical twisting power of chiral compounds, and fabrication of a architecture that combined Ch and twist grain boundary phase nanostructures. Based on these studies, the reflection bandwidth of ChLC has been greatly broadened in each material system, which makes it possible to practical applications. And there are still much works to be done in the future in making innovations in ChLC materials with excellent optical performance, improving performances of functional devices and developing preparation technologies or procedures for industrial production.