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Direct Hot-Injection Synthesis of Lead Halide Perovskite Nanocubes in Acrylic Monomers for Ultrastable and Bright Nanocrystal–Polymer Composite Films
摘要： In recent years, lead halide perovskite nanocrystals (NCs) have attracted significant attention in both fundamental research and commercial applications due to their excellent optical and optoelectrical properties. However, the protective ligands on the surface of the perovskites NCs could be easily removed after the tedious process of centrifugation, separation, and dispersion, which greatly hampers their stability against light, heat, moisture, and oxygen and limits their practical applications. Here we report a new post-processing-free strategy (i.e., without centrifugation, separation, and dispersion process) of using an UV-polymerizable acrylic monomer of lauryl methacrylate (LMA) as the solvent to synthesize CsPbBr3 NCs, and then adding polyester polyurethane acrylates oligomer, monomer (IBOA) and initiator for directly UV polymerization to fabricate NC-polymer composite films. These films exhibited an improved photoluminescence quantum yield (85-90%) than classic NC-film (40-50%), which were processed using octadecene (ODE) as the solvent for NC synthesis and post-processed for UV polymerization. Significantly, the as-fabricated films by post-processing-free strategy exhibited excellent photostability against strong Xe lamp illumination; while the other films using classic methods were quickly photo-degraded. Meanwhile, these NC-polymer composite films showed good stability against moisture and heating when aging in water at 50oC for over 200 hours. These films, along with K2SiF6:Mn4+ (KSF) phosphor emitters, were used as downconverters for blue LEDs in liquid crystal displays with a wide color gamut of 115% in the International Commission on Illumination (CIE) 1931 color space. This work provides a facile and effective strategy for the preparation of ultrastable and bright color-conversion NC films for the development of the next-generation wide color gamut displays.
关键词： display backlight,lead halide perovskite,colloidal nanocrystals,color-conversion optical films,photostability
更新于2025-11-14 17:03:37
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Integration of chiral cellulose nanocrystal films in silica optical fibers
摘要： Cellulose nanocrystals have attracted great attention as new “wonder” materials for photonic applications owing to their unique property of spontaneous self-assembly to form chiral nematic films. Here, the incorporation of chiral cellulose nanocrystal films on a photonic waveguide is demonstrated for the first time – in the form of integrated silica optical fibers with a helicoid nanocrystal film on their input facet. In order to achieve repeatable cholesteric ordering across the fiber core modal area, a fabrication method was developed where several optical fiber facets form part of a larger flat surface, which acts as the substrate for the planar anchoring of the cellulose nanocrystals. The resultant optical fibers exhibit significant circular dichroism (almost 40%) in transmission and act as all-fiber spectral filters. The proposed fabrication technique provides a simple, low-cost method for developing chiral silica optical fibers that remain compatible with standard telecommunication fiber technology. It is envisioned that the incorporation of cellulose nanocrystals in other optical fiber types will enable the development of a new class of fiber devices.
关键词： optical films,optical device fabrication,optical materials,optical polarization,fiber optics,optical fibers,optical fiber devices
更新于2025-09-23 15:19:57
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An Overview of Research into Low Internal Friction Optical Coatings by the Gravitational Wave Detection Community
摘要： The direct detection of gravitational waves by ground-based interferometric gravitational wave detectors in recent years has opened a new window of the universe, allowing the astrophysical observations of previously unexplored phenomena, such as the collisions of black holes and neutron stars. However, small thermodynamic fluctuations of the density of the thin films that compose the mirrors used within the gravitational wave detectors, such as the LIGO and Virgo detectors, give rise to noise which limits these instruments at their most sensitive frequencies. This 'Brownian Thermal Noise' can be related to the inherent internal friction of the mirror materials through the fluctuation-dissipation theorem. Therefore, the improved sensitivity of gravitational wave detectors depends, to some extent, upon the development of optical thin films with low internal friction. The past two decades have therefore seen the growth of internal friction experiments undertaken within the gravitational wave detection community. This article attempts to summarize the results of these investigations and to highlight current research directions in order to foster a stronger dialogue with the larger internal friction and mechanical spectroscopy community.
关键词： LIGO,Optical Films,Internal Friction
更新于2025-09-19 17:15:36