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Cholesteric phase liquid crystal films capable of selectively reflecting incident light over a wide range of wavelengths have significant potential for optical applications. However, the preparation of cholesteric phase liquid crystal films which reflect a wider broadband using simple methods has been a technical challenge. In this study, we have successfully fabricated a bilayer liquid crystal film with chiral and non-chiral layers by simply superimposing a layer of nematic liquid crystals to a cholesteric phase liquid crystal layer. Due to the synergistic effect between the diffusion rate and the polymerization rate of the polymerizable monomer in the bilayer structure, the pitch distribution of the polymerized bilayer liquid crystal film is not uniform, and the final cholesteric-phase liquid crystal film obtained can reflect circularly polarized light over a wide wavelength range of more than 1500 nm. We briefly tested the infrared shielding performance of this bilayer-structured liquid crystal film. The glass with the bilayer structured cholesteric phase liquid crystal film was heated up significantly slower than the unsampled blank glass. The final temperature difference between the two glasses reaches 33 °C within the same irradiation time (10 min). This result indicates that the film has excellent IR reflective properties for IR light. This study not only provides a new strategy for the preparation of cholesteric phase liquid crystal films, but also offers a new idea for the preparation of smart windows with IR shielding properties for optical applications. [ABSTRACT FROM AUTHOR]

Polymer dispersed liquid crystals (PDLC) and polymer stabilised cholesteric liquid crystals (PSCLC) are an indispensable class of electrically switchable materials, which have been widely applied in the fabrication of efficient and systematic smart windows. And doping nanoparticles in PDLC films can greatly improve their properties. In this study, PDLC films doped with zirconia nanoparticles were prepared by polymerisation-induced phase separation (PIPS) method, PSCLC films with nematic liquid crystals as the main part (reflecting wavelengths in the range of 400–600 nm) were prepared by UV curing method, and a novel optical switch was developed by combining these two liquid crystal films. The optimal bilayer sample was developed through a comparative analysis of properties among samples with varying formulations for each liquid crystal layer. This study represents a novel advancement in PSCLC and nanoparticle-doped PDLC bilayer structures, showcasing fully actuatable properties in the visible wavelength range. These structures exhibit excellent electro-optical properties and demonstrate stable, sustainable performance that can be regenerated. The findings underscore the potential of PDLC and PSCLC for applications in smart curtains and flexible materials, opening up new avenues for innovative technological applications. [ABSTRACT FROM AUTHOR]

Organic ultra-long room temperature phosphorescence (OURTP) has been widely used in applications including encryption and anti-counterfeiting. However, little research has focused on circularly polarised luminescence (CPL) with RTP materials. In order to construct circularly polarised room temperature phosphorescent (CP-RTP) materials with highly efficient luminescent properties, we report on the synthesis of a novel chiral phosphorescent molecule and its immobilization in a dynamically crosslinked Vitrimer film. The lifetime and quantum yield of the green persistent RTP are 895 ms and 9.70%, respectively, and the dissymmetry factor (glum) is up to 0.014. In addition, it exhibits good thermal stimulus response properties, which remain unchanged under repeated multiple cycles of heating/cooling, and it can be further widely used in the field of encryption of optical information and other applications. [ABSTRACT FROM AUTHOR]

Electrically driven multi-stable cholesteric liquid crystals can be used to adjust the transmittance of incident light. Compared with the traditional liquid crystal optical devices, the multi-stable devices only apply an electric field during switching and do not require a continuous electric field to maintain the various optical states of the device. Therefore, the multi-stable devices have low energy consumption and have become a research focus for researchers. However, the multi-stable devices still have shortcomings before practical application, such as contrast, switching time, and mechanical strength. In this article, the latest research progress on electrically driven multi-stable cholesteric liquid crystals is reviewed, including electrically driven multi-stable modes, performance optimization, and applications. Finally, the challenges and opportunities of electrically driven multi-stable cholesteric liquid crystals are discussed in anticipation of contributing to the development of multi-stable liquid crystal devices. [ABSTRACT FROM AUTHOR]