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Light–matter interaction in quantum materials presents a new paradigm as light can tip the balance between many competing quantum many-body phases to result in new phenomena. Describing the optical response of such materials requires complex models. Here, we develop a non-local model to describe the optical response of a quantum material, 1T- TaS 2. 1T- TaS 2 is a charge density wave material that supports competing stacking configurations of its charge domains. The presence of various stacking domains results in an inhomogeneity that necessitates a non-local dielectric function. We experimentally measure the non-local optical response of 1T- TaS 2 films under various illumination intensities and validate our model. The non-local parameter extracted from our measurements sheds light on the competition between the two stacking configurations of 1T- TaS 2. Our technique of measuring non-local optical response serves as a quick, simple, and non-invasive method to probe the energy landscape of strong correlations in many such quantum materials. [ABSTRACT FROM AUTHOR]

Physical processes involving hot electrons, including their generation, transport, injection, and relaxation, have been an extensive area of research. The most widely utilized method for actuating the creation of hot electrons involves the excitation of plasmonic modes followed by their non-radiative decay, channeling the energy into these energetic carriers. Since plasmonics has already evolved into a mature field of scientific exploration, active plasmonic devices serve as an ideal platform to study hot-electron physics. In this Perspective article, we will provide the reader with a comprehensive outline of the physics underlying hot-electron dynamics. Emphasis will be placed on the characteristic timescales involved with the lifecycle of hot electrons, the generation and decay mechanisms of surface plasmon-induced hot electrons, and the material platforms suitable for such a study. Then, we will move on to discuss different temperature models used to explain the evolution of hot electrons and the changes in the optical properties of the materials they are generated in or injected into. Finally, we will focus on some of the interesting optical phenomena occurring at ultrafast timescales mediated by hot-carrier dynamics. Such a discussion is expected to incorporate valuable insights into our understanding of the synergistic relationship between hot-electron dynamics and active plasmonics, thereby paving the way for novel applications involving optoelectronics and energy conversion. [ABSTRACT FROM AUTHOR]

We explore piezooptic and photoelastic properties of Ca3Ga2Ge4O14 (CGG) crystals. A Mach–Zehnder interferometry technique is utilized to determine a complete set of the piezooptic tensor constants πim, with particular attention to the measurement accuracy, reliability, and uncertainty resolution in the piezooptic measurements. For these reasons, independent piezooptic constants or their combinations were determined by performing interferometric measurements for different geometries of piezooptic coupling using samples of both principal (direct) and non-principal (X/45°) crystallographic cuts. Basing on the results of piezooptic measurements, a complete set of photoelastic tensor constants pim and the acousto-optic performance (figure of merit M2) of CGG crystals were evaluated. The obtained piezooptic, photoelastic, and acousto-optic characteristics of CGG crystals are compared with those of other crystals of the langasite group, langasite and CTGS (Ca3TaGa3Si2O14). A comparative analysis reveals a correlation between the values of the piezooptic or photoelastic constants and the lattice parameters for this group of crystals. High optical quality and optical transparency in the UV region of the spectrum up to 260 nm together with extremely high mechanical resistance to uniaxial compression (≤2000 kg/cm2) opens up the possibility for specific application of CGG crystal as an optical material for piezooptic sensors of high uniaxial compression. The presented piezooptic interference technique along with methodological and metrological approaches paves the way for accurate and unambiguous characterization of photoelastic crystal materials of trigonal symmetry. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal chalcogenides (2D TMCs) like MoS2, WS2 etc., have established significant dominance in the field of nanoscience and nanotechnology, owing to their unique properties like strong light–matter interaction, high carrier mobility, large photo-responsivity etc. Despite the widespread utilization of these binary TMCs, their potential in the advancement of the optoelectronic research is limited due to the constraints in band tuning and charge carrier lifetime. To overcome these limitations, ternary transition metal chalcogenides have emerged as promising alternatives. Although, the optical properties of these materials have never been explored properly. Herein, we have investigated one such promising member of this group, Cu2MoS4 (CMS) using both steady state and time-resolved spectroscopic techniques. The material exhibits a broad range of visible light absorption, peaking at 576 nm. Photoluminescence spectroscopy confirmed the presence of both band gap emission and trap state-mediated emissions. Transient absorption spectroscopy unraveled the excited state charge carrier dynamics of CMS in sub-ps timescale, upon irradiation of visible light. We found significant influence of the trap mediated recombination, while Auger process being dominant at high charge density. We extended our study in a wide temperature range (5–300 K), which reveals the impact of electron-phonon coupling strength on the band gap and charge carrier dynamics of this material. This detailed study would draw more attention toward the unexplored optical properties of ternary 2D chalcogenides and will open new avenues for the construction of 2D material-based optical devices. [ABSTRACT FROM AUTHOR]

The ability to control the optical properties of a material with an electric field has led to optical memory devices, communication systems, optical signal processing, or quantum cryptography. Understanding electro-optic effects, especially in thin films, would improve the efficiency of these applications. In particular, the influence of epitaxial strains is of prime importance. In addition, the active control of these effects would be of great interest to tailor the material to the desired performance. Here, we demonstrate through first-principle calculations that the linear electro-optic response (Pockels effect) of two silicon-compatible ferroelectrics is stable with respect to bi-axial strain and that the electro-optic response can be strongly enhanced through the electrical control of the polarization. We attribute the former to the lack of optical phonon softening and a weak elasto-optic response and the latter to the externally induced softening of a phonon of symmetry A 1. Our results are readily applicable to other polar materials and show that the electro-optic effect can be efficiently engineered to meet the performance criteria of future technologies. [ABSTRACT FROM AUTHOR]

This study presents a novel hydrothermal method for synthesizing Cu 11 Zn 1 Sb 4 S 13 (tetrahedrite, zincian) nanoparticles at a low temperature of 185 °C for a 6 h annealing at 400 °C for 2 h. CuCl 2 , ZnCl 2 , SbNO 3 , and CH 4 N 2 S, and NaBH 4 were used for the innovative synthesis of Cu 11 Zn 1 Sb 4 S 13 (Tetrahedrite, Zincian) Copper Zinc Antimony Sulfide nanoparticles ink. Structural, morphological and optical properties (optical energy gap) were studied for thin-film Cu 11 Zn 1 Sb 4 S 13 deposited the nanoparticles via drop-casting method onto glass substrates are investigated. The structure and characterization of Cu 11 Zn 1 Sb 4 S 13 by XRD powder diffraction provide evidence for a cubic structure. The optical calculations indicate that the absorption coefficient (α > 104 cm−1) and optical energy gap E g are equivalent to 1.68 eV. Comparative work of Crystalline diameters of synthesis was obtained from XRD diffraction powder. The Debye-Scherrer procedure, modified Scherrer procedure and Williamson–Hall inspection are used to examine the individual participatory of the crystalline diameters, lattice stress and dislocation to isotropic line expansion widening reflection peaks of Cu 11 Zn 1 Sb 4 S 13 nanoparticles. The modified Scherrer approach is appropriate, with all points along the fitting line. The crystallite size estimated from XRD was 5.798 nm and the particle size calculated from the FESEM method 8–9 nm. This slight difference reflects a spherical shape of the nanoparticles. [ABSTRACT FROM AUTHOR]

Europium(III) (Eu3+/Eu(III)) substitution in the hydroxyapatite (HAp) lattice imparts luminescence properties, enabling its application in diagnostics and bioimaging. Despite numerous experimental studies, there has been a lack of comprehensive discussion on the substitution behavior and local structural stability of Eu3+ within HAp. In this study, experimental and first-principles investigations were integrated to explore and understand the substitution of Eu3+ in HAp. Optimization of various HAp models revealed the dependency of Eu3+ substitution site on the charge compensation mechanism. Eu3+ prefers the Ca(2) site when OH is converted to O and the Ca(1) site in the presence of a Ca vacancy. Phonon calculations showed that temperature influences charge compensation and site preference, favoring OH to O compensation and Eu3+ in Ca(2) at higher temperatures and Ca vacancy and Eu3+ in Ca(1) at lower temperatures. Electronic structure simulations explained that the luminescence in Eu(III)-substituted HAp primarily arises from charge transfer between Eu3+ and O atoms, supported by experimental photoluminescence measurements. Correspondence between simulations and experimental photoluminescence data emphasizes the reliability of the computational approach in this study. The integration of insights from experimental and simulation results enhances the understanding of substitution of Eu3+ in the HAp lattice, providing valuable guidance for designing and optimizing HAp-based luminescent and optical materials. [ABSTRACT FROM AUTHOR]

Anisotropy is crucial for birefringence (Δn) in optical materials, but optimizing it remains a formidable challenge (Δn >0.3). Supramolecular frameworks incorporating π‐conjugated components are promising for achieving enhanced birefringence because of their structural diversity and inherent anisotropy. Herein, we first synthesized (C6H6NO2)+Cl− (NAC) and then constructed a halogen‐bonded supramolecular framework I+(C6H4NO2)− (INA) by halogen aliovalent substitution of Cl− with I+. The organic moieties are protonated and deprotonated nicotinic acid (NA), respectively. The antiparallel arrangement of birefringent‐active units in NAC and INA leads to significant differences in the bonding characteristics between the interlayer and intralayer domains. Moreover, the [O⋅⋅⋅I+⋅⋅⋅N] halogen bond in 1D [I+(C6H4NO2)−] chain exhibits stronger interactions and stricter directionality, resulting in a more pronounced in‐plane anisotropy between the intrachain and interchain directions. Consequently, INA exhibits exceptional birefringent performance, with a value of 0.778 at 550 nm, twice that of NAC (0.363 at 550 nm). This value significantly exceeds those of commercial birefringent crystals, such as CaCO3 (0.172 at 546 nm), and is the highest reported value among ultraviolet birefringent crystals. This work presents a novel design strategy that employs halogen bonds as connection sites and modes for birefringent‐active units, opening new avenues for developing high‐performance birefringent crystals. [ABSTRACT FROM AUTHOR]

Assembly of 2D molecules into hierarchical structures opens new avenues for creating multifunctional materials, yet fabricating the optical materials with multiscale structural features, and extending functions in a controllable way remains a challenge. Here, an asynchronous liquid depositing strategy is introduced that enables the asymmetrical growth of 2D covalent organic frameworks (COFs) on a graphene substrate. This results in Janus composite (JC) materials with independently controlled mesoscopic features, such as the COF layer thickness (100–300 nm), and its nanoflake length (0–200 nm), and thickness (0–30 nm). The JCs exhibit impressive light coupling capabilities and display a wide range of angle‐independent structural colors. These colors can be dynamically and reversibly changed in 10 ms when exposed to volatile organic compounds (VOCs). They also demonstrate remarkable tailorability to form both random and ordered patterns which shows excellent information processing potential. These unique properties make JCs highly suitable as novel responsive optical devices for collecting and processing information about their surroundings, as demonstrated by visual and real‐time VOC monitoring and localization in both open and confined spaces. It is believed that the controlled assembly of 2D components into composites with well‐organized hierarchical structures will facilitate the future development of extraordinary materials with extensive applications. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) can self‐assemble to form cholesteric liquid crystal, which make it one of the most promising optical materials at present. CNCs can be produced by sulfuric acid hydrolysis. It is found that hydrolysis conditions influence the existing form of reaction components and their reaction activities, which leads to different reaction routes and mechanisms under varied reaction conditions, with CNCs of varied quality produced. High‐quality CNC with more uniform particle size could be prepared at a critical acid concentration of 64 wt%, which was used to study the formation process of CNC liquid crystal and the structure regulation of cholesteric liquid crystal. By adjusting the drying temperature and adding a small molecule of water‐soluble chitosan (WSC) can well regulate cholesteric liquid crystal and change the pitch of a film, and the reflection wavelength can be redshifted, thus enriching texture patterns and creating distinctive color. Suitable addition of WSC can enhance the multi‐domain effect during liquid crystal formation process and finally creates more colorful film with fine texture. The rich and tunable liquid crystal characteristics endowed by WSC addition is irreplicable and artistic, which helps to realize the great potential application of the composite film in advanced anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Optical imaging is a powerful tool for early disease detection and effective treatment planning, but its accuracy is often compromised by the uptake of imaging materials by the mononuclear phagocyte system (MPS). Herein, we leverage multivalent host-guest interactions between cyanine dyes and ß-cyclodextrin polymers to develop supramolecular probes with enhanced stability, optical, and transport profiles for accurate in vivo imaging. These multivalent interactions not only ensure the stability of the probes but also enhance fluorescence efficiency by minimizing nonradiative decay. Our self-assembly approach effectively modulates probe size and surface properties, enabling evasion of MPS clearance and promoting prolonged bloodstream circulation, thereby improving the signal-to-background ratio for imaging. The effectiveness of our design is demonstrated by substantial advancements in the early diagnosis of acute kidney injury and by providing high-contrast imaging and precise surgical navigation across various tumor models. Our strategy not only advances optical imaging materials toward clinical translation but also establishes a versatile platform applicable to multiple imaging modalities. [ABSTRACT FROM AUTHOR]

Unlike traditional group‐6 transition metal dichalcogenides (TMDs), group‐10 TMDs such as PtSe2 and PdTe2 possess highly tuneable indirect bandgaps, transitioning from semiconducting in the near‐infrared to semimetal behavior with a number of monolayers (MLs). This opens up the possibility of TMD‐based mid‐infrared and terahertz optoelectronics. Despite this large potential, the optical properties of such materials have shown an extremely large disparity between that predicted and measured. For example, simulations show that a few MLs is required for the semiconductor–semimetal transition, whilst tens of MLs is found experimentally. This is a result of widely used optical extrapolation methods to determine bandgaps, such as the Tauc plot approach, that are not adapted here owing to i) nearby direct transitions, ii) the material dimensionality and iii) large changes in the non‐parabolic bandstructure with MLs. Here, uniquely combining optical ellipsometry to determine the complex permittivity, terahertz time resolved spectroscopy for the complex conductivity and in‐depth density functional theory (DFT) simulations, it is shown that the optical properties and bandstructure can be determined reliably and demonstrate clearly that the semiconductor‐semimetal transition occurs for PtSe2 layers ≈5 MLs. The microscopic origins of the observed transitions and the crucial role of the Coulomb interaction for thin semiconducting layers, and that of interlayer van der Waals forces for multilayer semimetallic samples are also demonstrated. This work of combining complimentary experimental techniques and extensive simulations avoids the application of constrained extrapolation methods to determine the optical properties of group‐10 TMDs, and will be of importance for future mid‐infrared and terahertz applications. [ABSTRACT FROM AUTHOR]

Anisotropic optical 2D materials are crucial for achieving multiple‐quanta functions within quantum materials, which enables the fabrication of axially polarized electronic and optoelectronic devices. In this work, multiple excitonic emissions owning polarization‐sensitive orientations are clearly detected in a multilayered quasi‐1D ZrS3 nanoribbon with respect to the nanostripe edge. Four excitons denoted as AS1, AS2, AS, and A2 with E ⊥ b polarized direction and one prominent A1 exciton with E || b polarized emission are simultaneously detected in the polarized micro‐photoluminescence (µPL) measurement of 1.9–2.2 eV at 10 K. In contrast to light emission, polarized micro‐thermoreflectance (µTR) measurements are performed to identify the polarization dependence and verify the excitons in the multilayered ZrS3 nanoribbon from the perspective of light absorption. At 10 K, a prominent and broadened peak on the lower‐energy side, containing an indirect resonant emission (DI) observed by µPL and an indirect defect‐bound exciton peak (AInd) observed by both µPL and µTR, is simultaneously detected, confirming the existence of a quasi‐direct band edge in ZrS3. A van der Waals stacked p‐GaSe/n‐ZrS3 heterojunction solar cell is fabricated, which demonstrates a maximum axially‐polarized conversion efficiency up to 0.412% as the E || b polarized light incident onto the device. [ABSTRACT FROM AUTHOR]

Plasmonic nanoparticles enable manipulation and enhancement of light fields at deep subwavelength scales, leading to structures and devices for diverse applications in optics. Despite hybrid plasmonic materials display remarkable optical properties due to interactions between components in nanoproximity, scalable production of plasmonic nanostructures within a single‐crystalline matrix to achieve an ideal plasmon–crystal interface remains challenging. Here, a novel approach is presented to realize efficient manipulation of in‐lattice plasmonic nanoparticles. Employing ultrafast‐laser‐driven plasmonic nanolithography, metallic nanoparticles with controllable morphology are precisely defined in the crystalline lattice of yttrium aluminum garnet (YAG) crystal. Through direct ion implantation, hybrid plasmonic material composed of nanoparticles embedded in a sub‐surface amorphous YAG layer is created. Subsequently, femtosecond laser pulses guide formation and reshaping of plasmonic nanoparticles from the amorphous layer into the single‐crystalline matrix along direction of light propagation, facilitated by a plasmon‐mediated evolution of laser energy deposition. By tailoring resonance modes and optimizing the coupling between structured particle assemblies, a range of applications including polarization‐dependent absorption and nonlinearity, controllable photoluminescence, and structural color generation is demonstrated. This research introduces a new approach for fabricating advanced optical materials featuring in‐lattice plasmonic nanostructures, paving the way for the development of diverse functional photonic devices. [ABSTRACT FROM AUTHOR]

Optical diamond materials are essential for infrared optical windows, microwave windows, and laser windows due to their exceptional properties. However, dark features inside the diamond are significant factors limiting optical properties, particularly at high deposition rates. This work focuses on adjusting crystallographic parameters to prepare (110) oriented optical-grade polycrystalline diamond films, aiming to mitigate dark features. Diamond films deposited via microwave plasma chemical vapor deposition (MPCVD) exhibit discernible quality stratification. Characterization analysis of diamond film samples with varying levels of black defects reveals a correlation: films with higher dark feature content tend to exhibit a preference for the (111) orientation, accompanied by a significant presence of penetration twins and interstitial voids. Conversely, transparent diamond films demonstrate a prominent (110) orientation, featuring numerous contact twins that alleviate competition from penetration twins and original grains during growth. Electron backscatter diffraction (EBSD) and scanning electron microscope (SEM) results reveal that transparent diamond films cultivated with a pronounced preference for the (110) orientation manifest consistent and seamless contact twins, leading to fewer dark features and improved optical transmittance. In contrast, (111) oriented diamond film exhibits numerous penetration twins, and holes form between them. Based on the analysis, 5-inch optical polycrystalline diamond films with (110) orientation were achieved successfully by suppressing dark features. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting for hydrogen production represents a crucial approach for obtaining green energy through artificial solar energy utilization, offering a sustainable method for energy generation that helps mitigate energy shortages and protect the environment. Among the numerous photocatalytic materials, covalent organic frameworks (COFs) have garnered significant attention and intensive study from researchers due to their distinctive benefits, such as porosity, pre‐design capability, and tunability at the atomic level. Significant advancements are made in the development of materials, enhancement of performance, and comprehension of mechanisms. In this review, recent advancements in COF‐based photocatalytic water splitting are spotlighted, both in half‐reactions and overall reactions, with a particular emphasis on the rational design of COF structures to regulate the materials' optical and electrical properties, as well as the fundamental processes of photocatalysis. Drawing from current research in this field, the existing challenges, and potential opportunities are also discussed for future development. [ABSTRACT FROM AUTHOR]

Despite the rising advances in the field of all-inorganic CsPb2Br5-based materials and their photoelectronic applications, the exploitation of facile synthetic procedures and enhancement of optical properties remain challenging. Herein, we report a facile room-temperature aqueous phase synthesis of orange-red-emitting cation-doped and codoped CsPb2Br5 materials with enhanced photoluminescence (PL) performance and stability. Only a very weak broad PL peak at around 618 nm is observed in the undoped CsPb2Br5 microsheets. However, doping with Cu and codoping with Cu/Mn, Cu/Zn or Cu/Cd significantly enhance the PL intensity of the resulting CsPb2Br5-based samples. The stability of the representative Cu-doped and various codoped CsPb2Br5 samples is evaluated under various conditions such as soaking in water, high temperature up to 150 °C, and an ambient environment at room temperature. This work provides a facile and cost-effective path for large-scale and controlled synthesis of orange-red emissive CsPb2Br5-based materials with enhanced optical performances, excellent environmental stability, and potential in LEDs. [ABSTRACT FROM AUTHOR]

Achieving highly efficient absorption in the short wavelength infrared (SWIR) spectral region is crucial for advancing numerous technologies. SWIR absorption enhances energy harvesting in solar cells, improves the sensitivity of infrared sensors, and enables precise control of thermal radiative properties in thermal emission devices. These advancements are essential for applications such as thermal imaging, night vision, and thermophotovoltaic systems. The study presents a simple, cost‐effective design of a polymer‐coated multilayer perfect absorber (MPA) metamaterial optimized for the SWIR spectral region. The proposed MPA structure is composed of four distinct layers: a top layer made of polymethyl methacrylate (PMMA) polymer, a second layer featuring arrays of circular titanium nitride (TiN) disks, a dielectric middle layer consisting of a pure zinc oxide (ZnO) film, and a bottom metallic layer formed by a thin film of TiN. The results demonstrate that the MPA achieves near‐perfect absorption, with a remarkable 99% efficiency centered at a wavelength of 1.3 µm. The absorption properties are further investigated with respect to various structural parameters to ensure better performance of the absorber. These absorbers hold great promise for applications in energy absorption, infrared sensing, thermal emission, and related fields. [ABSTRACT FROM AUTHOR]

Many non-destructive optical testing methods are currently used for material research, providing various information about material parameters. At RECENDT, a multimodal experimental setup has been designed that combines terahertz (THz) spectroscopy, optical coherence tomography (OCT), infrared (IR), and Raman spectroscopy with a tensile test stage. This setup aims to gather material information such as crystallinity and optical parameters of high-density polyethylene (HDPE) during a tensile test. The setup compares common IR and Raman spectroscopy and the less common optical methods THz and OCT. Complementarity is achieved through different frequency ranges and measurement approaches, resulting in different measured optical material parameters and depths. During tensile testing, HDPE samples with varying crystallinity were analysed, and the determined optical parameters such as refractive index, birefringence, scattering coefficient of decay, and penetration depth can be correlated with the change in crystallinity. These findings demonstrate that the optical methods and their outcomes can be interconnected. With further optimization of the experimental setup, it would be possible to observe the alignment of fibres in fibre composite panels and the stress distribution of polymers effectively. This opens interesting possibilities for polymer characterization in the future, including quality control during moulding processes and material testing. [ABSTRACT FROM AUTHOR]

The exploration of photon avalanching (PA) luminescence in different lanthanide emitters has profound implications in plentiful frontier applications. However, studies for universal mechanisms at the nanoscale to exhibit giant nonlinear responses in various avalanching emitters are limited. Here, record‐breaking nonlinear responses up to 60th‐order in high‐lying emitting levels of various emitters at room temperature are generated by proposing a universal mechanism named energy relay‐mediated photon avalanche (enrePA). By harnessing energy from the avalanching nano‐engine through the energy relay of Yb3+ ions, the brightness of blue emissions from Tm3+ and Ho3+ can be enhanced with giant optical nonlinearity up to 60th and 38th order, respectively. Further incorporating gadolinium‐based systems, more emitters (Tb3+, Eu3+, Dy3+, Nd3+) can be activated with extreme optical nonlinearities up to 48th‐order. By expanding PA into the full‐spectrum range, the enrePA mechanism opens exciting avenues for flexible and high‐efficiency PA modulation in multilayer nanostructures, enabling the applicability of PA in more technologies such as super‐resolution imaging, lithography, and optical detection. [ABSTRACT FROM AUTHOR]

This study explores the modeling, design, simulation, and testing of a new composite material designed for high-strength and high-temperature resistance in in-space optical mining, examining its properties at both the polymer and atomic/molecular levels. At the polymer level, the investigation includes mechanical and thermal performance analyses using COMSOL Multiphysics 6.1, employing layerwise theory, equivalent single layer (ESL) theory, and a multiple-model approach for mechanical modeling, alongside virtual thermal experiments simulating laser heating. Experimentally, porous Polyaniline (PANI) films are fabricated via electrochemical polymerization, with variations in voltage and deposition time, to study their morphology, optical performance, and electrochemical behavior. At the atomic and molecular levels, this study involves modeling the composite material, composed of Nomex, Kevlar, and Spirooxazine-Doped PANI, and simulating its behavior. The significance of this work lies in developing a novel composite material for in-space optical mining, integrating it into optical mining systems, and introducing innovative thermal management solutions, which contribute to future space exploration by improving resource efficiency and sustainability, while also enhancing the understanding of PANI film properties for in-space applications. [ABSTRACT FROM AUTHOR]

In the present research article, the structural, electronic, and optical characteristics of a novel perovskite halide, Mg3AsCl3, for a broad range of applications are thoroughly investigated. The characteristics of Mg3AsCl3 perovskite are investigated via the use of the generalized gradient approximation (GGA), Perdew–Burke–Ernzerhof and Heyd–Scuseria–Ernzerhof (HSE06) functionals, which are employed in conjunction with the linear combination of atomic orbital calculator. The structural, electrical, and optical characteristics of the material are investigated using density‐functional theory. In this study of the electronic characteristics, it is found that Mg3AsCl3 exhibits an indirect energy bandgap of 2.49 eV with GGA and 3.54 eV with HSE06. The complex band structure exhibits characteristics that indicate the presence of evanescent waves, which are characterized by a layer separation of 5 Å. The report in this research presents reflectivity values of 0.06328 and 0.02971 with GGA and HSE06 functionals, respectively. The reported values of the extinction coefficient are 3.36487 × 10−5 and 2.07389 × 10−5 calculated with GGA and HSE06 functionals. The value reported for the real dielectric function Re[ε] is 2.79625 with GGA and 2.00658 with HSE06. Overall, in these findings, an overview is given that Mg3AsCl3 holds potential as a candidate for use in a wide range of electronic device applications. [ABSTRACT FROM AUTHOR]

Responsive chiral optical materials have gained considerable interests from the fields of sensing, display, and optical devices. Materials that are capable of changing chiral optics under harsh conditions such as strong basic/acidic or ultrahigh temperature provides thoughts for the design of materials working at special environments, which however, are still underdeveloped. Here, a proof‐of‐concept design of organogel is reported that acts as matrices for thermal chiroptical switch with critical working temperature above 100 °C. The reversible solution‐to‐gel transition of the specific β‐cyclodextrin/dimethyl formide/LiCl system is initialized at about 130 °C, when the luminophores with aggregation‐induced‐emission property shall be lighted up with transferred chirality from inherent chiral β‐cyclodextrin. It allows for the controlled emergence of circularly polarized luminescence. This delicate design enables successful fabrication of ultrahigh temperature thermal chiroptical switch. [ABSTRACT FROM AUTHOR]

Passive radiative cooling is a zero‐energy consumption approach, which can dissipate heat to outer space by emitting infrared radiation through the transparency window. Traditional cooling materials, such as photonic films, metafabrics, and polymer foams, still suffer from complex preparation processes and high costs. In this work, it is reported that natural cellulose can be converted into a "green" optical metamaterial by rational structure reconfiguration at the micro/nano level via scalable ball milling technology for efficient daytime radiative cooling. Specifically, fine‐tuning the shearing kinetics in the mechanochemistry process, cellulosic optical metamaterial (COM) with ≈98% solar reflectivity and ≈0.97 infrared emissivity has been successfully achieved, which can break through the theoretical value of photonic crystals as well as the conventional synthetic optical materials. The COMSOL simulation reveals that the excellent optical properties of the cellulose metamaterial are explained by the "confined scattering" effect caused by the rearranged heterostructure at the micro/nano level. Outdoor tests demonstrat that the COM‐based coating exhibits a daytime radiative cooling efficiency of 5.7 °C in hot Nanjing. Meanwhile, the COM can be produced into different scattering materials via spray coating, freeze casting, and solution casting technology. This study will facilitate the development of scalable and sustainable optical metamaterials for mitigating energy consumption. [ABSTRACT FROM AUTHOR]

Persistent luminescence (PersL) has attracted considerable attention in the last two decades for its potential applications in the fields of emergency indicators, energy‐saving lighting, biomedical imaging, and dynamic anti‐counterfeiting. However, the wavelengths of PersL reported so far usually fall into the visible and near‐infrared range. The preparation of advanced optical materials bearing UV PersL remains elusive. Here the PersL characteristic of CaF2:Gd3+ is systematically studied. After exposure to X‐ray radiation, CaF2:Gd3+ continues to emit UV­‐B (UVB) PersL peaking at 313 nm, corresponding to the 6P7/2 → 8S7/2 transition of Gd3+. By virtue of X‐ray photoelectron spectroscopy measurements, the valence variation model is excluded to explain the UVB PersL of CaF2:Gd3+. Finally, it is demonstrated that such UVB PersL of CaF2:Gd3+ can be used for static labeling and dynamic tracing. [ABSTRACT FROM AUTHOR]

The films of P(4ClAni)/CuO, which formed of mixing poly 4-chloroaniline P(4ClAni) by CuO, were fabricated by the casting solution method. The XRD confirmed the successful prepration of the P(4ClAni)/CuO films. Additionally, the effect of CuO on the optical characteristics was determined. The CuO increased the refractive index from 1.09 for P(4ClAni) to 1.11 for P(4ClAni)/CuO-1, and 1.19 for P(4ClAni)/CuO-3, respectively, while the oscillation energy E0 dropped from 4.29 eV for P(4ClAni) to 3.57 eV for P(4ClAni)/CuO-1, 3.12 eV for P(4ClAni)/CuO-2, and 3.06 eV for P(4ClAni)/CuO-3. The charge transfer between P(4ClAni) and CuO increased optical conductivity as the CuO ratios increased. This suggests that modifications in the electronic structure of the composite due to the interactions between P(4ClAni) and CuO. Also, the plasma frequency increased from 0.87 x 1012 s−1 to 2.32 x 1012 s−1. These changes in optical parameters occurred when the polarization of the P(4ClAni)/CuO was altered. The study elucidated the advantages of incorporating CuO nanoparticles as fillers in improving the properties of P(4ClAni) structures. The obtained results indicate the P(4ClAni)/CuO composites were sucessfuly fabricated with novel characteristics that can be applied in flexible optical devices. [ABSTRACT FROM AUTHOR]

Liquid phase exfoliation of non-van der Waals materials has generated renewed interest in fundamental optical and electronic materials discovery and processing. However, such approaches can limit access to novel two-dimensional materials due to the chemistry of exfoliation and processing conditions employed (e.g., processing temperature, mechanical energy input, volatile organic compounds, and sensitive redox chemistries). Here, we demonstrate the exfoliation of bulk hematite (α-Fe2O3) powder using a mild bath sonication methodology in liquid monomer media to form stable colloidal dispersions with quasi-two-dimensional hematene nanoflakes. These colloidal dispersions were further processed to form hematene poly(methyl methacrylate) matrix composite substrates. [ABSTRACT FROM AUTHOR]

Persistent luminescence (PersL) materials attract extensive interest in the scientific community nowadays due to their great potential in various fields, such as night‐vision signage, high‐level anticounterfeiting, in vivo bioimaging, and X‐ray extension imaging. However, the majority of PersL materials are synthesized by time‐ and energy‐consuming processes such as high‐temperature solid‐state reactions or hydrothermal synthesis. In this work, a rapid one‐step microwave‐assisted solid state (MASS) synthesis of La2MgGeO6‐based robust double perovskite PersL material is successfully achieved, without any secondary thermal treatment, which limits the total synthesis time to 30 min. Furthermore, this MASS approach is also employed to integrate multimodal luminescence into one single La2MgGeO6 matrix with triple dopants (Mn4+, Yb3+, and Er3+) for light conversion. Impressively, multimodal and multicolor luminescence is obtained with different responsiveness of external stimulations. Notably, the energy transfer among different trapping levels is observed upon photo‐stimulation. This work provides a good example of the feasibility of MASS method to prepare luminescent materials with abundant optical features in an efficient, sustainable, environmentally friendly, and easily manageable way. [ABSTRACT FROM AUTHOR]

Increased energy consumption, driven by climate change and the rise of new industries, has spurred a demand for alternative cooling technologies to replace energy‐intensive systems and mitigate environmental pollution. Radiative cooling, leveraging the optical properties of materials to cool without emitting pollutants or consuming energy, is considered a suitable solution. Among the various form of radiative cooling devices, paint stands out as a practical application for radiative cooling. Hence, a passive daytime radiative cooling (PDRC) paint is developed using a polyurethane binder and zeolitic imidazolate framework (ZIF)‐8. ZIF‐8 is synthesized in an environmentally friendly manner using deionized water as the solvent, resulting in paint with a reflectance of 94.9%, emissivity of 94%, and cooling power of 113 W m−2. Temperature measurements reveal that the paint reduced ambient temperatures by an average of 5.7 °C, reaching up to 8.1 °C during the day. Additionally, with a self‐assembly monolayer coating, the PDRC surface exhibited super‐hydrophobicity and self‐cleaning capabilities. Therefore, the proposed ZIF‐8‐based PDRC paint offers sub‐room temperature cooling potential and is anticipated to reduce energy consumption for cooling, thereby alleviating environmental pollution in various applications, particularly in building exteriors. [ABSTRACT FROM AUTHOR]

Remote detection and mapping of surface materials using optical sensors relies predominantly on analyzing multispectral and hyperspectral imagery employing classification algorithms. The classification process involves comparing the spectra of individual pixels within the image to spectra from reference databases, commonly referred to as spectral libraries. Here, we introduce a comprehensive compilation of spectral libraries specifically tailored for petroleum hydrocarbons (PHC), meticulously crafted under controlled laboratory conditions. This compilation includes reference spectral libraries for various PHC forms, including crude oils, mineral substrate-PHC mixtures (comprising crude oils and fuels), oil-film on water, and oil-water emulsions. Data collection was conducted within the visible, near, and shortwave IR (VNIR-SWIR – 0.35–2.5 µm) spectra and thermal IR (TIR – 3–15 µm) range. The openly accessible spectral libraries presented herein support the scientific community and industry in characterizing field samples or spectral data from onshore and offshore sites. Furthermore, these libraries are instrumental in developing and applying classification algorithms designed for processing spectral images captured by cameras coupled to multiple platforms (e.g., tripods, drones, airborne, orbital satellites). [ABSTRACT FROM AUTHOR]

In this study, we present a novel broadband microwave absorber that is both optically transparent and capable of dynamically adjusting its absorptivity. The absorber is composed of a graphene sandwich structure (GSS), a polyvinyl chloride (PVC) layer, an indium tin oxide (ITO) layer, another PVC layer, and an ITO ground plane, arranged in a top-to-bottom configuration. This unique design allows for a working bandwidth of 6.8 GHz to 14.0 GHz, with absorption levels ranging from 95% to 60%, achieved by varying the impedance of the GSS from 1000 Ω/sq to 200 Ω/sq through tuning the bias voltage. By utilizing materials with high optical transmittance, this nonpatterned device maintains exceptional optical transparency. Furthermore, by incorporating additional ITO layers with different impedances at equal intervals, this multilayer design can be extended to create an ultra-broadband absorber covering a range of 5.28–39.52 GHz. This is made possible due to the dispersionless resistance of nonpatterned graphene and ITO sheets in the microwave spectrum. This transparent wideband microwave absorber, with tunable absorptivity, holds great potential for a wide range of applications in broadband and intelligent stealth technology [ABSTRACT FROM AUTHOR]

To overcome the small sensitivities of luminescent manometers, Mn2+‐activated Zn2GeO4 green‐emitting phosphors with admirable manometric characteristics are synthesized. The structural stability of the studied samples is theoretically and experimentally investigated. Moreover, as pressure elevates, a huge spectral red‐shift and a broadening of the emission band are observed in studied samples, contributing to color‐tunable luminescence, i.e., from green to yellow, and ultimately to orange–red. Specifically, when pressure increases to 6.76 GPa, the emission band centroid shifts from 535.9 to 634.9 nm, leading to a superior sensitivity of dλ/dp = 21.3 nm/GPa. Whereas, in the same operating pressure range, the full width at half maximum (FWHM) of the emission band rises from 32.3 to 102.9 nm, resulting in unprecedentedly high sensitivity of dFWHM/dp = 17.0 nm/GPa. Furthermore, through analyzing the pressure‐dependent color coordinates, a maximum sensitivity of 29.43% GPa−1 is achieved, when x‐coordinate is adopted. Additionally, the applicability of the developed manometer is confirmed by a simple uniaxial pressure experiments to showcase its practical use in industrial and daily‐life purposes. Notably, the designed sensor exhibits the highest pressure sensitivities reported to date in different modes, namely, emission band centroid, FWHM and color coordinate, making supersensitive multimodal optical manometry a reality. [ABSTRACT FROM AUTHOR]

Bandgap is a key property that determines electrical and optical properties in materials. Modulating the bandgap thus is critical in developing novel materials particularly semiconductors with improved features. This study examines the bandgap, highest occupied molecular orbital (HOMO), and lowest unoccupied molecular orbital (LUMO) energy level trends in a metal organic framework, metal–organic framework 5 (MOF‐5), as a function of Hammett substituent effect (with the constant σm in the meta‐position of the benzene ring) and solvent dielectric effect (with the constant ε). Specifically, experimental design and response surface methodologies helped to assess the significance of trends and correlations between these molecular properties with σm and ε. While the HOMO and LUMO decrease with increasing σm, the LUMO exhibits greater sensitivity to the substituent's electron withdrawing capability. The relative difference in these trends helps to explain why the bandgap tends to decrease with increasing σm. [ABSTRACT FROM AUTHOR]

Metamaterial has been captivated a popular notion, offering photonic functionalities beyond the capabilities of natural materials. Its desirable functionality primarily relies on well-controlled conditions such as structural resonance, dispersion, geometry, filling fraction, external actuation, etc. However, its fundamental building blocks--meta-atoms--still rely on naturally occurring substances. Here, we propose and validate the concept of gradient and reversible atomic-engineered metamaterials (GRAM), which represents a platform for continuously tunable solid metaphotonics by atomic manipulation. GRAM consists of an atomic heterogenous interface of amorphous host and noble metals at the bottom, and the top interface was designed to facilitate the reversible movement of foreign atoms. Continuous and reversible changes in GRAM's refractive index and atomic structures are observed in the presence of a thermal field. We achieve multiple optical states of GRAM at varying temperature and time and demonstrate GRAM-based tunable nanophotonic devices in the visible spectrum. Further, high-efficiency and programmable laser raster-scanning patterns can be locally controlled by adjusting power and speed, without any mask-assisted or complex nanofabrication. Our approach casts a distinct, multilevel, and reversible postfabrication recipe to modify a solid material's properties at the atomic scale, opening avenues for optical materials engineering, information storage, display, and encryption, as well as advanced thermal optics and photonics. [ABSTRACT FROM AUTHOR]

Photonic crystals are a new class of optical microstructure materials characterized by a dielectric constant that varies periodically with space and features a photonic bandgap. Inspired by natural photonic crystals such as butterfly scales, a series of artificial photonic crystals are developed for use in integrated photonic platforms, biosensing, communication, and other fields. Among them, colloidal photonic crystals (CPCs) have gained widespread attention due to their excellent optical properties and advantages, such as ease of preparation and functionalization. This work reviews the classification and self‐assembly principles of CPCs, details some of the latest biomedical applications of large‐area, high‐quality CPCs prepared using advanced self‐assembly methods, summarizes the existing challenges in CPC construction and application, and anticipates future development directions and optimization strategy. With further advancements, CPCs are expected to play a more critical role in biosensors, drug delivery, cell research, and other fields, bringing significant benefits to biomedical research and clinical practice. [ABSTRACT FROM AUTHOR]

Photomodulable fluorophores constitute advanced materials as they possess the ability to modify their photophysical properties upon photoirradiation. A new mechanism of photoconversion is recently established, called Directed Photooxidation Induced Conversion based on the coupling of fluorophores with Aromatic Singlet oxygen Reactive Moieties (ASORMs). In this work, The Directed Photooxidation Induced Conversion (DPIC) mechanism is intended to be applied to Perylene BisImide (PBI) due to its appealing photophysical properties. The experimental results showed that coupling two ASORMs to the PBI core, here furan and pyrrole, led to impressive photomodulable fluorophores. While PBI‐F exhibited a photoconversion of 100 nm shift, PBI‐P displayed an 80‐fold fluorescence intensity enhancement upon photoactivation. Analysis of the photoproducts showed that the conversion do not involve an addition of singlet oxygen on the ASORM. Instead, photoconversion occurred through efficient successive photocyclizations. Finally, intracellular vesicles are successfully photoconverted by means of endocytosed PLGA‐polymer nanoparticles loaded with PBI‐F. This study highlights the unique capability of furan‐ and pyrrole‐conjugated fluorophores to enable advanced optical materials with phototransformation properties. [ABSTRACT FROM AUTHOR]

Circularly polarized light (CPL) has attracted great attention due to its unique electromagnetic vector, which possesses potential practical applications in optical imaging, biometrics, and other interdisciplinary areas. At present, many materials with spontaneous CPL emitting have been extensively studied and reviewed for the generation of CPL. For the detection of CPL, mainly concentrate on the technical problems, that is, how to combine circularly polarized optical active materials with device structures to meet detection needs. Essentially, the resolution of CPL depends on the interaction between CPL and matter, Herein, the interactive modes including polarized light‐spin and light‐dipole (or charge) interactions in devices are summarized. Also, direct and indirect interactions of polarized light‐spin are presented. Meanwhile, the progress of light‐spin/dipole interaction dependence of CPL detectors is analyzed based on artificial structures of photoconductors, photodiodes, and photo field effect transistors. It is hoped that the review can broaden the bridge between the fundamental photon‐spin‐dipole interaction and CPL detectors with high performance, and then deepen the understanding of CPL detection and promote the development of CPL detectors. [ABSTRACT FROM AUTHOR]

This year marks the 50th anniversary of a significant milestone in organic optoelectronics, i.e., the first account of metallic-like conductivity in an entirely organic material, tetrathiafulvalene–tetracyanoquinodimethane (TTF–TCNQ). Since the discovery of this prototypical TTF–TCNQ charge-transfer (CT) pair, countless studies, ranging from various aspects, have been done on this fascinating TTF–TCNQ and related CT complexes. More recently, the CT complex-based approach has emerged as an elegant way of designing various next-generation functional organic materials, viz. room temperature phosphorescent (RTP), thermally activated delayed fluorescent (TADF), near infra infrared (NIR) emissive, organic spin-systems, etc. This highlight discusses how the synergy between computational screening and crystal engineering principles can be used to obtain the desired functional output and modulate the CT complex's bulk optical and electronic features. Emphasis is given to some of the recent non-covalent CT complex-based approaches to designing functional optical materials like RTP, TADF, NIR-emissive, chiral CT complex, etc. [ABSTRACT FROM AUTHOR]

The bandgap and operation stability of metal halide perovskites (MHPs) based light‐emitting diodes (PeLEDs) have been compromised by the substantial surface defect densities in the matrix. Today's defect passivation strategies rely on coordination actions of small‐molecular and/or polymeric ligands, which effectively enhance the optical properties of materials. However, the non‐trivial insulating characteristics of the molecules concurrently sacrifice the operation stability and external quantum efficiency (EQE) of the PeLEDs by augmenting the charge injection barrier at the interface. Herein, a coordinative, charge‐polarized organic semiconductor exhibiting thermally activated delayed fluorescence (TADF), namely 9,9‐dimethyl‐10‐(4‐(phenyl sulfonyl)phenyl)‐9,10‐dihydroacridine (SO‐DMAc) is coordinated, into the MHPs matrix for deep‐red PeLEDs. Owing to the distinctive charge transfer (CT) between the molecule and MHPs with exclusive coordination at the MHP's bottom, SO‐DMAc serves as a molecular bridge that significantly augments the hole injection into the PeLEDs. Encouraged by these improvements, efficient and stable deep red PeLEDs offering EQE of 21.8% and respective half lifetimes (T50) of luminance and EQE exceeding 6 and 35 h are demonstrated. It is revealed that the molecular coordination to the MHP surface is pivotal to manifesting the interfacial CT process for favorable energy level tuning. [ABSTRACT FROM AUTHOR]

Low‐dimensional lead halide perovskites demonstrate remarkable nonlinear optical characteristics attributed to their distinctive physical structures and electronic properties. Nevertheless, the investigation into their nonlinear optical properties remains in its incipient stages. This study addresses this gap by precisely controlling solvent volumes to synthesize both 0D Cs4PbBr6 and Cs4PbBr6/CsPbBr3 perovskites. Remarkably, as saturable absorbers, both pure Cs4PbBr6 and Cs4PbBr6/CsPbBr3 composites exhibit favorable nonlinear optical properties within the C‐band, showcasing modulation depths of 9.22% and 16.83%, respectively. Moreover, for the first time, Cs4PbBr6 and Cs4PbBr6/CsPbBr3 composites have been successfully integrated into erbium‐doped fiber lasers to realize the mode‐locking operations. The utilization of the Cs4PbBr6/CsPbBr3 composites as a saturable absorber that enables the generation of conventional soliton mode‐locked laser pulses with a pulse duration of 688 fs, and a repetition frequency of 10.947 MHz at a central wavelength of 1557 nm. Cs4PbBr6 is instrumental in generating laser pulses at a frequency of 10.899 MHz, producing pulse widths of 642 fs at the central wavelength of 1531.2 nm and 1.02 ps at the central wavelength of 1565.3 nm, respectively. The findings of this investigation underscore the potential utility of 0D Cs4PbBr6 and Cs4PbBr6/CsPbBr3 composites as promising materials for optical modulation within fiber laser applications. [ABSTRACT FROM AUTHOR]

AbstractPolymer-based composites are highly regarded as favorable candidate materials for dielectrics in high-energy-density capacitors, owing to their exceptional flexibility and fast charge-discharge capabilities. Recently, multilayer-structured polymer composites have gained significant attention as a promising solution for energy storage and dielectric applications, offering a combination of high energy density and low dielectric loss. These polymer multilayer films, comprising two or more layers synthesized through specific fabrication processes, have presented extensive uses in various applications, including packaging and optical materials, such as oxygen barrier, holographic anti-counterfeiting, and optical sensing, due to their versatile and tunable functionalities. The distinctive chemical composition and structural design of these layers, whether symmetrically or gradient distributed, endow these dielectric composites with superior integrated electric properties. This review provides a comprehensive overview of fabrication methods and strategies employed in the latest advancements in dielectric multilayer-structured polymers for energy storage applications. It delves into the design and manufacturing techniques of advanced multilayer composites, highlighting the diverse strategies utilized to enhance energy performance, such as polarization manipulation, electric field distribution control, interfacial modification, and geometric confinement of interfaces within both organic and organic/inorganic multilayer-structured composites. Lastly, this review addresses the current challenges and future prospects in the development of multilayer composites with enhanced energy storage performance. [ABSTRACT FROM AUTHOR]

All passive metamaterials are inherently narrowband due to fundamental dispersion-energy constraints, and their dispersive properties are usually approximated by a Lorentz model. However, there are broadband active metamaterials in the radio frequency (RF) regime based on negative capacitors with non-Foster dispersion properties. Non-Foster dispersion is usually considered as an "electronic-engineering trick" that cannot be applied at optical frequencies. Here, we demonstrate that the dispersion relation of a RF non-Foster capacitor is similar to that of an optical gain material described by a Lorentz model. This insight paves the way to realize non-Foster optical metamaterial structures. As the simplest example, we develop a broadband non-Foster optical epsilon-near-zero slab with a 1:10 bandwidth. [ABSTRACT FROM AUTHOR]

Pollution caused by heavy metal ions has become a global issue owing to their severe threat to the ecological environment and human health. However, it remains a considerable challenge to detect heavy metal ions in an efficient, selective, and high signal‐to‐noise ratio way. Herein, a portable and sensitive method is presented to probe Hg2+ by using an ultralong afterglow dispersion. The in situ encapsulation of phosphorescent carbon dots (CDs) within rigid hydrogen‐bonded organic frameworks (HOFs) leads to ultralong room temperature phosphorescence (RTP) in water with a maximum lifetime of up to 974.86 ms. Moreover, the resultant CDs@HOFs material exhibits robust and long‐term RTP emission with enhanced performance under strongly acidic or alkaline conditions, which contributes to the practical detection of Hg2+ in water. As such, an efficient and sensitive afterglow probe is facilely fabricated by integrating CDs@HOFs with a Hg2+ probe Rhodamine B derivative (RhBTh), demonstrating selective sensing of Hg2+ with greatly improved signal‐to‐noise ratios based on the triplet‐singlet Förster resonance energy transfer system (TS‐FRET). This work not only provides a reliable and versatile method for realizing robust RTP emission in water, but also expands the applications of afterglow materials in the field of optical sensing of toxic analytes. [ABSTRACT FROM AUTHOR]

Two novel diamines 1‐(4‐aminophenyl)‐1,3,3‐trimethyl‐2,3‐dihydro‐1H‐indene‐5‐amine and 4‐amino‐N‐(4‐(5‐(4‐aminobenzamide)‐1,3,3‐trimethyl‐2,3‐dihydro‐1H‐inden‐1‐yl) phenyl) benzamide containing indene and amide groups were successfully designed and synthesized, and a series of colorless polyimides (CPIs) derived from the two diamines with 1,2,4,5‐cyclohexanetetracarboxylic dianhydride in various ratios were copolymerized. The introduction of aliphatic ring structures was conducive to the improvement of optical properties, while the incorporation of amide groups improved thermal and mechanical properties. These CPI films exhibited excellent optical properties (T400 > 80%), high heat resistance (Tg > 300 °C) and mechanical properties with the synergistic action of the two groups. Furthermore, the effect of the content of amide groups on the intermolecular interaction of CPIs was systematically analyzed. This study provides a fancy method for the development of heat‐resistant colorless materials for optical applications. [ABSTRACT FROM AUTHOR]

In this groundbreaking study, we unveil the remarkable structural, electronic, and optical Properties of the newly discovered double perovskite material, K2AgBiI6, presenting a paradigm shift in materials science. The unique crystal structure and diverse atomic interactions inherent in this double perovskite make it an up-and-coming candidate for various technological applications, particularly in photovoltaics; owing to its stability and resistance to heat and humidity, we aim to shed light on the extraordinary potential of K2AgBiI6. Our study provides valuable insights for researchers engaged in tailored material design. We anticipate that the exceptional electronic properties of K2AgBiI6 will not only redefine the boundaries of materials engineering but also catalyze unprecedented advances in sustainable technology. Employing the powerful computational tool CASTEP, we conducted detailed electronic structure calculations within the framework of Density Functional Theory (DFT) to unravel the electronic properties of the double perovskite K2AgBiI6. Our investigation thoroughly explored structural properties, band structure, total density of states (DOS), and partial density of states (PDOS). Furthermore, we systematically examined the influence of different exchange-correlation functionals, including LDA, GGA, and m-GGA, on the electronic and optical features of the material by presenting a comparative analysis of these approximations. [ABSTRACT FROM AUTHOR]

Lignin is the main component of plant cell walls, conferring upon lignocellulosic biomass both excellent mechanical and barrier properties. At the same time, the considerable number of unsaturated groups and conjugated structures present in lignin render it a promising candidate for applications in the optical domain. In recent years, the development of the optical properties of lignin and lignin-derived optical materials has paved the way for a novel avenue of lignin valorization. This review is concerned with the mechanisms of lignin-derived optical materials, with particular emphasis on the physical and chemical structures that are linked to their optical performance, including UV absorption, photothermal conversion, and photoluminescence. Additionally, the potential applications of these materials in energy storage, bioimaging, structural materials, and photonic crystal are also presented, demonstrating the unique optical properties of lignin. Finally, the challenges and future directions of lignin as an optical material are presented, with the objective of developing lignin into a polymer biobased raw material that can serve advanced emerging industries. [ABSTRACT FROM AUTHOR]

Modulating the assembly pathway is an indispensable strategy for optimizing the performance of optical materials. However, implementing this strategy is nontrivial for metal nanocluster building blocks, due to the limited functional modification of nanoclusters and complexity of their emission mechanism. In this report, we demonstrate that a gold nanocluster modified by 4,6‐diamino‐2‐pyrimidinethiol (DPT‐AuNCs) self‐assembles into two distinct aggregation structures in methanol (MeOH)/water mixed solvent, thus exhibiting pathway complexity. Kinetic studies show that DPT‐AuNCs firstly assembles into non‐luminescent nanofibers (kinetically controlled), which further transforms into strongly luminescent microflowers (thermodynamically controlled). In‐depth analysis of the assembly mechanism reveals that the transformation of aggregation structures involves the disassembly of nanofibers and a subsequent nucleation‐growth process. Temperature‐dependent photoluminescence (PL) spectroscopy and infrared (IR) measurements reveal that inter‐cluster hydrogen bonding bridged by solvent molecules and C−H⋅⋅⋅π interaction are the key factors for emission enhancement. The photoluminescent property of DPT‐AuNCs can be controlled by varying the cosolvent in water, enabling DPT‐AuNCs to distinguish different kind of alcohols, particularly the isomerism n‐propanol (NPA) and isopropanol (IPA). Additionally, the addition of seeds effectively regulate the assembly kinetics of DPT‐AuNCs. This study advances our understanding of assembly pathways and improves the luminescent performance of nanoclusters (NCs). [ABSTRACT FROM AUTHOR]

The advancement of Eu2+‐activated luminescent materials tailored to exhibit a range of properties is crucial for addressing the specific demands of various application fields. However, the lack of suitable lattice sites in numerous compounds for stable Eu2+ incorporation restricts their potential for diverse optical properties. Herein, a facile strategy of carbon and hydrogen coreduction utilizing graphite crucibles is proposed to effectively achieve the impressive luminescence of Eu2+ at trivalent Y sites in Rb3Y(PO4)2:Eu phosphors. Rb3Y(PO4)2:Eu exhibits blue‐violet emission when Eu2+ predominantly occupies the Rb1 and Rb2 sites. Inspiringly, by facilitating the reduction of more Eu3+ to Eu2+, a yellow emission band at 550 nm arising from Eu2+ at Y sites emerges, enabling the realization of single‐component white‐emitting and yellow‐emitting Rb3Y(PO4)2:Eu phosphors. The diverse luminescent properties of Rb3Y(PO4)2:Eu expand its potential applications in different white light source devices and optical thermometry. This work presents an innovative synthetic strategy to develop remarkable Eu2+ luminescence at trivalent cation sites, thereby broadening the optical properties of the material and enabling multifunctional applications. [ABSTRACT FROM AUTHOR]

The sensitive and rapid detection of thermal neutrons holds significant importance in various fields such as energy utilization, medical treatment, and national defense. However, the available thermal neutron scintillator is difficult to reach this target, mainly limited by the optical and scintillating performance. Herein, the in situ crystallization strategy of glass to construct scintillation glass composites for efficient thermal neutron detection is proposed. The congruent crystallization of the hybridized alkali earth silicate glass system may not only achieve high crystallinity, but also will keep the refractive indexing matching between the precipitated crystal and precursor glass phases. The prepared glass composites feature high luminescence efficiency, optical transmission and excellent neutron response properties. These factors collectively contribute to the robust neutron scintillation performance with a light output of ≈36 000 photons/neutron, which represents the highest value among glass‐based scintillators. Moreover, the composite configuration brings about the additional function of thermal neutron and γ‐ray discrimination. By using this composite scintillator, the neutron detector is constructed and demonstrates its application for detecting thermal neutron and distinguishing it from γ‐ray in an online way. The studies prove that glass composites with high crystallinity are expected to be promising candidates for a new generation of multifunctional neutron detectors. [ABSTRACT FROM AUTHOR]

Organic optical waveguide materials have attracted considerable attention for their promising applications in photonic and optoelectronic devices. However, for most materials, excellent light‐loss properties at high temperature cannot be obtained due to many factors. Consequently, realizing efficient optical waveguide materials that perform well at elevated temperatures remains a significant challenge. In this study, relying on the luminescent properties and self‐assembly properties of luminescent liquid crystals (LLCs), successfully fabricated materials are present for highly efficient active optical waveguides. A systematically synthesized set of LLCs with different structures is named according to the substituent type and the position of the cyano group, namely α‐DECN, α‐DEEOCN, β‐DECN, and β‐DEEOCN. Notably, α‐DECN and β‐DECN reveal hexagonal columnar phase, while α‐DEEOCN and β‐DEEOCN exhibit smectic phase. Optical waveguide experiments have revealed that the obtained LLCs showed highly efficient optical waveguide behavior, where the lowest light loss reached 0.15 dB mm−1 at room temperature. Remarkably, these LLCs show even lower light loss at high temperatures, with the light loss reaching 0.11 dB mm−1 as the lowest point. Further experimental results indicate that this phenomenon is attributed to the change in the dipole moment of these molecules. This research forms a significant groundwork for advanced exploration in optical waveguide material. [ABSTRACT FROM AUTHOR]