Advanced Optical Materials最新文献

Multi-Analyte Gas Sensor Array using Zirconium-Organic Frameworks

This cover image features a toxic gas flow interacting with sensing films (polyvinylidene fluoride membranes) containing the fluorescent metal-organic frameworks (porous interpenetrated zirconium-organic frameworks) that have been studied by Francisco G. Moscoso, José María Pedrosa, and co-workers in article number 2401081. This interaction produces distinct fluorescence changes in the films, which, once processed, give rise to unique recognition patterns.

Nanocolumnar Metamaterial Platforms

Ufuk Kilic, Mathias Schubert, and co-workers (see article number 2302767) report the general scaling rules for the optical anisotropy of nanocolumnar structures using the Mueller matrix spectroscopic ellipsometry technique. Their findings demonstrate the extreme sensitivity of optical anisotropy to the changes in the critical dimensions of nanocolumns, potentially paving the way for a transformative new class of nano-metrology. As an outlook, the research highlights the significant potential of these metamaterial platforms in advancing nanoparticle sensing and infiltration mechanisms.

Lead halide perovskite nanocrystals are attractive for light emitting devices both as electroluminescent and color-converting materials since they combine intense and narrow emissions with good charge injection and transport properties. However, while most perovskite nanocrystals shine at green and red wavelengths, the observation of intense and stable blue emission still remains a challenging target. In this work, a method is reported to attain intense and enduring blue emission (470–480 nm), with a photoluminescence quantum yield (PLQY) of 40%, originating from very small CsPbBr₃ nanocrystals (diameter < 3 nm) formed by controllably exposing Cs₄PbBr₆ to humidity. This process is mediated by the void network of a mesoporous transparent scaffold in which the zero-dimensional Cs₄PbBr₆ lattice is embedded, which allows the fine control over water adsorption and condensation that determines the optimization of the synthetic procedure and, eventually, the nanocrystal size. The approach provides a means to attain highly efficient transparent and stable blue light-emitting films that complete the palette offered by perovskite nanocrystals for lighting and display applications.

Hybrid Resonant Metasurfaces with Configurable Structural Colors

In article number 2401501, Jelena Wohlwend and co-workers introduce a novel type of hybrid metasurface, based on non-primitive amorphous silicon nanocups. This innovative design enables the generation of configurable structural colors with extra ordinary resolution, showcasing the advanced capabilities of hybrid metasurfaces.

Motheye-Like Metastructures with Broadband Infrared Antireflectivity

Materials possessing broadband antireflective properties benefit applications of military camouflage, photovoltaic devices, and highly transparent windows. In this work (see article number 2401341 by Zeyu Zhao, Xiangang Luo, and co-workers), large-area subdiffraction-limited motheye-like metastructures with broadband infrared antireflectivity are realized by dual-beam overexposure shrinking strategy and controllable anisotropic reactive ion etching process. A reflectivity across the overall spectrum of 3–12 µm lower than 2.0% is demonstrated.

Free carrier absorption (FCA) is established to be the cause of nonlinear losses in plasma-enhanced chemical vapor deposition (PECVD) silicon-rich nitride (SRN) waveguides. To validate this hypothesis, a photo-induced current is measured in SRN thin films with refractive indices varying between 2.5 and 3.15 when a C-band laser light is illuminating the SRN films at various powers, indicating the generation of free carriers. Furthermore, nonlinear loss dynamics is, for the first time, measured and characterized in detail in SRN waveguides by utilizing high peak power C-band complex shape optical pulses for estimation of free carrier generation (FCG) and free carrier recombination (FCR) lifetimes and their dynamics. Both FCG and FCR are found to decrease with an increase in the refractive index of SRN, and, specifically, the FCR lifetimes are found (92 ± 7) ns, (39 ± 3) ns, and (31 ± 2) ns for the SRN indices of 2.7, 3, and 3.15, respectively. Lastly, nonlinear losses in high refractive index SRN waveguides are demonstrated to be minimized and altogether avoided when the pulse duration reduced below the free carrier generation lifetime, thus providing a way of taking a full advantage of the large inherent SRN nonlinear properties.

Environment-benign ZnSeTe quantum dots (QDs) are regarded promising blue electroluminescent (EL) emitters alternative to Cd-based ones for the next-generation QD-display platform. Herein, the core/shell heterostructural variation of blue-emitting ternary ZnSeTe QDs by manipulating ZnSeTe core size (small versus large) and ZnSe inner shell thickness (thin versus thick), while ZnS outer shell thickness remains unaltered, is explored. EL outcomes of the resulting core/shell QDs having photoluminescence quantum yields of 59−80% within the blue color regime (454−463 nm) are found to be dependent on their heterostructural dimension, exhibiting the highest performances of 31709 cd m⁻² in luminance and 11.4% in external quantum efficiency (EQE) from large-ZnSeTe/thick-ZnSe/ZnS QDs. Furthermore, to address the chronic issues of excessive electron injection and exciton quenching at emitting layer/electron transport layer (ETL) interface, the surface of ZnMgO (ZMO) nanoparticle (NP) is modified by bicarbonate functional species. Bicarbonate passivation not only leads to the effective reduction of defective sites on the ZMO NP surface toward the suppression of exciton quenching but induces the upshift of ETL band alignment in favor of charge balance. As a result, the optimized blue device incorporated with bicarbonate-functionalized ZMO NPs delivers a peak luminance of 39739 cd m⁻² and a maximum EQE of 17.1%.

Efficient Molecular Array Control and Vapochromic Behavior Changes

The study by Kyung-Ryang Wee and co-workers in article number 2401305 introduces a strategy to control molecular arrays by modifying the shapes of donor–acceptor–donor building blocks via positional isomerism. Molecular shape variations lead to distinct arrays, affecting intermolecular interactions and void volumes, influencing the macrostructure and resulting in different vapochromic behaviors.