Emission Properties Research Articles

Mechanical properties and damage characteristics analysis on recycled aggregate concrete with glazed hollow beads after high temperatures by acoustic emission method

This research investigates the effect of high temperature on the mechanical and acoustic emission properties of recycled aggregate concrete with glazed hollow beads (GHB-RAC). Uniaxial compression tests were conducted on GHB-RAC at varying recycled coarse aggregate (RCA) substitution rates and glazed hollow beads (GHB) contents, and acoustic emission (AE) technology was used to monitor the compression-induced damage throughout the testing process. This study delves into the mechanical properties and damage characteristics of GHB-RAC when exposed to fire. The findings reveal that AE characteristic coefficients aptly delineate the three-stage nature of axial compression damage in concrete at temperatures up to 400 °C. However, these stage-specific traits vanish at temperatures exceeding 400 °C. Additionally, through the analysis of AE signals at different temperatures, the compression damage process is elucidated based on the b-value method. The RA-AF analysis indicates that the number of shear cracks exhibits an increasing trend with increasing temperature, and an increment in GHB dosage positively influences the percentage of tensile cracking during loading, with the influence being more significant at 70 % GHB content. The acoustic emission sensing can accurately detect and localise damage. With the increase in temperature, the distribution of AE signals depicting concrete damage is more dispersed and the number of AE signals is more larger. Notably, the incidence of localized damage points diminishes with a higher GHB ratio, indicating the efficacy of GHBs in mitigating thermal damage to the concrete. Furthermore, a damage constitutive model incorporating variables such as temperature, GHB dosage, and recycled coarse aggregate replacement rate was proposed. The model employed AE energy count parameters as the damage indicator. The good fitting results suggest that the mechanics behavior of GHB-RAC under uniaxial compression can be well described by the model. Consequently, the study offers invaluable insights into the damage evolution of post-fire recycled aggregate concrete with GHB admixtures.

Recent advances in biomimetic aggregation‐induced emission photosensitizers for photodynamic therapy and immunotherapy

AbstractThe development of novel photosensitizers (PSs) with aggregation‐induced emission (AIE) properties has emerged as a crucial advancement in the field of photodynamic therapy (PDT). However, the versatile applications of AIE PSs are limited by low encapsulation efficiency and inadequate target tissue permeability. Biomimetic technology stands out as a promising strategy to overcome these challenges, aiming to enhance AIE PSs tumor penetration efficacy, and their association with antitumor immune responses. In this review, recent advancements in biomimetic AIE PSs for PDT and immunotherapy are summarized. We start with introducing strategies involving biomimetic AIE PSs based on cell membranes and extracellular vesicles for the combined application of PDT and immunotherapy. We then discuss the preparation of biomimetic AIE PSs nanoparticles. Finally, we briefly outline the challenges and prospects associated with biomimetic AIE PSs.

A Novel Enhanced-Fluorescent Probe Based on DHLA-Stabilized Red-Emitting Copper Nanoclusters for Methimazole Detection Via Aggregation-Induced Emission Effect.

Herein, an aqueous phase synthesis approach was presented for the fabrication of copper nanoclusters (Cu NCs) with aggregation-induced emission (AIE) property, utilizing lipoic acid and NaBH4 as ligands and reducing agent, respectively. The as-synthesized Cu NCs exhibit an average size of 3.0 ± 0.2nm and demonstrate strong solid-state fluorescence upon excitation with UV light. However, when dissolved in water, no observable fluorescent emission is detected in the aqueous solution of Cu NCs. Remarkably, the addition of Methimazole induced a significant red fluorescence from the aqueous solution of Cu NCs. This unexpected phenomenon can be ascribed to the aggregation of negatively charged Cu NCs caused by electrostatic interaction with positively charged imidazole groups in Methimazole, resulting in enhanced fluorescence through AIE mechanism. Therefore, there exists an excellent linear correlation between the fluorescent intensities of Cu NCs aqueous solution and the concentration of Methimazole within a range of 0.1-1.5 mM with a low limit of detection of 82.2 µM. Importantly, the designed enhanced-fluorescent nanoprobe based on Cu NCs exhibits satisfactory performance in assaying commercially available Methimazole tablets, demonstrating its exceptional sensitivity, reliability, and accuracy.

Trifluoromethylation of 2D Transition Metal Dichalcogenides: A Mild Functionalization and Tunable p‐Type Doping Method

AbstractChemical modification is a powerful strategy for tuning the electronic properties of 2D semiconductors. Here we report the electrophilic trifluoromethylation of 2D WSe2 and MoS2 under mild conditions using the reagent trifluoromethyl thianthrenium triflate (TTT). Chemical characterization and density functional theory calculations reveal that the trifluoromethyl groups bind covalently to surface chalcogen atoms as well as oxygen substitution sites. Trifluoromethylation induces p‐type doping in the underlying 2D material, enabling the modulation of charge transport and optical emission properties in WSe2. This work introduces a versatile and efficient method for tailoring the optical and electronic properties of 2D transition metal dichalcogenides.

Application of Mono and Trinuclear Cyclometalated Iridium (III) Complexes in Differential Bacterial Imaging and Antimicrobial Photodynamic Therapy.

The application of transition metal complexes for antimicrobial photodynamic therapy (PDT) has emerged as an attractive alternative in mitigating a broad range of bacterial pathogens, including multidrug-resistant pathogens. In view of their photostability, long excited-state lifetimes, and tunable emission properties, transition metal complexes also contribute as bioimaging agents. In the present work, we designed mono and trinuclear cyclometalated iridium (III) complexes to explore their imaging application and antibacterial potential. For this, we used Methicillin-resistant S. aureus (MRSA), the most prevalent of community-associated (CA) multidrug-resistant (MDR) bacteria (CA MDR) and Lactococcus lactis (L. lactis) as Gram-positive while Campylobacter jejuni (C. jejuni) and E. coli as Gram-negative bacteria. In addition to differential bioimaging of these bacteria, we assessed the antibacterial effects of both mono and trinuclear Ir(III) complexes under exposure to 427 nm LED light. The data presented herein strongly suggest better efficacy of trinuclear Ir(III) complex over the mononuclear complex in imparting photoinduced cell death of MRSA. Based on the safety profile of these complexes, we propose that trinuclear cyclometalated iridium(III) complex holds great promise for selective recognition and targeting MDR bacteria with minimal off-target effect.

Trifluoromethylation of 2D Transition Metal Dichalcogenides: A Mild Functionalization and Tunable p-Type Doping Method.

Chemical modification is a powerful strategy for tuning the electronic properties of 2D semiconductors. Here we report the electrophilic trifluoromethylation of 2D WSe2 and MoS2 under mild conditions using the reagent trifluoromethyl thianthrenium triflate (TTT). Chemical characterization and density functional theory calculations reveal that the trifluoromethyl groups bind covalently to surface chalcogen atoms as well as oxygen substitution sites. Trifluoromethylation induces p-type doping in the underlying 2D material, enabling the modulation of charge transport and optical emission properties in WSe2. This work introduces a versatile and efficient method for tailoring the optical and electronic properties of 2D transition metal dichalcogenides.

Potential Biomedical Applications of Terbium-Based Nanoparticles (TbNPs): A Review on Recent Advancement.

The scientific world is increasingly focusing on rare earth metal oxide nanomaterials due to their consequential biological prospects, navigated by breakthroughs in biomedical applications. Terbium belongs to rare earth elements (lanthanide series) and possesses remarkably strong luminescence at lower energy emission and signal transduction properties, ushering in wide applications for diagnostic measurements (i.e., bioimaging, biosensors, fluorescence imaging, etc.) in the biomedical sectors. In addition, the theranostic applications of terbium-based nanoparticles further permit the targeted delivery of drugs to the specific site of the disease. Furthermore, the antimicrobial properties of terbium nanoparticles induced via reactive oxygen species (ROS) cause oxidative damage to the cell membrane and nuclei of living organisms, ion release, and surface charge interaction, thus further creating or exhibiting excellent antioxidant characteristics. Moreover, the recent applications of terbium nanoparticles in tissue engineering, wound healing, anticancer activity, etc., due to angiogenesis, cell proliferation, promotion of growth factors, biocompatibility, cytotoxicity mitigation, and anti-inflammatory potentials, make this nanoparticle anticipate a future epoch of nanomaterials. Terbium nanoparticles stand as a game changer in the realm of biomedical research, proffering a wide array of possibilities, from revolutionary imaging techniques to advanced drug delivery systems. Their unique properties, including luminescence, magnetic characteristics, and biocompatibility, have redefined the boundaries of what can be achieved in biomedicine. This review primarily delves into various mechanisms involved in biomedical applications via terbium-based nanoparticles due to their physicochemical characteristics. This review article further explains the potential biomedical applications of terbium nanoparticles with in-depth significant mechanisms from the individual literature. This review additionally stands as the first instance to furnish a "single-platted" comprehensive acquaintance of terbium nanoparticles in shaping the future of healthcare as well as potential limitations and overcoming strategies that require exploration before being trialed in clinical settings.

Long-wave infrared emission properties of strain-balanced InAs/InxGa1−xAsySb1−y type-II superlattice on different substrates

Long-wave infrared emission properties of strain-balanced InAs/InxGa1−xAsySb1−y type-II superlattice on different substrates

The glass-forming region and 2.7 μm emission properties of Er3+-doped TeO2–MoO3–Nb2O5 tellurite glass

In this paper, the glass forming region of TeO2–MoO3–Nb2O5(TMN) tellurite glass and the luminescence properties of Er3+ doped TMN glass at 2.7 μm were studied. The effects of MoO3 on the thermal and optical properties of the glass were analyzed. The formation region of TMN glass was predicted by thermodynamic method and verified by experiment. It can be found that the glass-forming ability, thermal and optical properties of TMN glass change significantly with the change of MoO3 content. The addition of MoO3 significantly improves the anti-crystallization stability, fluorescence lifetime and quantum efficiency of tellurite glass. The calculation results show that the quantum efficiency of 80TeO2–15MoO3–5Nb2O5–1Er2O3 glass sample is 16 %. These results indicate that TMN glass has a broad application prospect in mid-infrared laser materials.

Morphology-controlled ZnO nanoarrays in situ grown on the basalt fiber surface for improving the interfacial properties of the high-performance thermoplastic composites

In this work, a biomimetic root-soil-like interfacial phase structure was constructed to improve the weak interfacial bonding of the fibers and resin based on the mechanical interlocking theory. Unidirectional basalt fiber (BF) reinforced high-temperature resistant thermoplastic poly (phthalazinone ether nitrile ketone) (PPENK, Tg = 278 °C) composites with multiscale structures were prepared. By utilizing a whiskerization technique, the zinc oxide nanoarrays (ZnO-NAs) with controllable morphologies grown on the BF surface through a pyrolysis-hydrothermal method. The remarkable field emission properties of the ZnO-NAs allow for visually characterizing the interfacial phase structures. The flexural, interlaminar shear, and interfacial shear strengths of BF-ZnO-PEI-2/PPENK composite were increased by 43 %, 65 %, and 177 %, respectively. Further investigations revealed that the flexural strength retention was 61 % at 250 °C, respectively. This study introduces a novel and viable approach to enhance the interfacial properties of BF-reinforced high-performance thermoplastic composites and expands their applications within high-temperature environments.

Nonlocal metasurface for dark-field edge emission.

Nonlocal effects originating from interactions between neighboring meta-atoms introduce additional degrees of freedom for peculiar characteristics of metadevices, such as enhancement, selectivity, and spatial modulation. However, they are generally difficult to manipulate because of the collective responses of multiple meta-atoms. Here, we experimentally demonstrate the nonlocal metasurface to realize the spatial modulation of dark-field emission. Plasmonic asymmetric split rings (ASRs) are designed to simultaneously excite local dipole resonance and nonlocal quasi-bound states in the continuum and spatially extended modes. With one type of unit, nonlocal effects are tailored by varying array periods. ASRs at the metasurface's edge lack sufficient interactions, resulting in stronger dark-field scattering and thus edge emission properties of the metasurface. Pixel-level spatial control is demonstrated by simply erasing some units, providing more flexibility than conventional local metasurfaces. This work paves the way for manipulating nonlocal effects and facilitates applications in optical trapping and sorting at the nanoscale.

Controllable Synthesis of Furan-Based Poly(ester amide)s and Its Study on Adhesive and Aggregation-Induced Emission Properties

Controllable Synthesis of Furan-Based Poly(ester amide)s and Its Study on Adhesive and Aggregation-Induced Emission Properties

Two-Photon-Responsive "TICT + AIE" Active Naphthyridine-BF2 Photoremovable Protecting Group: Application for Specific Staining and Killing of Cancer Cells.

The combined effects of twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE) phenomena have demonstrated a significant influence on excited-state chemistry. These combined TICT and AIE features have been extensively utilized to enhance photodynamic and photothermal therapy. Herein, we demonstrated the synergistic capabilities of TICT and AIE phenomena in the design of the photoremovable protecting group (PRPG), namely, NMe2-Napy-BF2. This innovative PRPG incorporates TICT and AIE characteristics, resulting in four remarkable properties: (i) red-shifted absorption wavelength, (ii) strong near-infrared (NIR) emission, (iii) viscosity-sensitive emission property, and (iv) accelerated photorelease rate. Inspired by these intriguing attributes, we developed a nanodrug delivery system (nano-DDS) using our PRPG for cancer treatment. In vitro studies showed that our nano-DDS manifested effective cellular internalization, specific staining of cancer cells, high-resolution confocal imaging of cancerous cells in the NIR region, and controlled release of the anticancer drug chlorambucil upon exposure to light, leading to cancer cell eradication. Most notably, our nano-DDS exhibited a substantially increased two-photon (TP) absorption cross section (435 GM), exhibiting its potential for in vivo applications. This development holds promise for significant advancements in cancer treatment strategies.

NIR‐II Absorption/Fluorescence of D–A π‐Conjugated Polymers Composed of Strong Electron Acceptors Based on Boron‐Fused Azobenzene Complexes

AbstractLuminescence in the second near‐infrared (NIR‐II, 1,000–1,700 nm) window is beneficial especially for deep tissue imaging and optical sensors because of intrinsic high permeability through various media. Strong electron‐acceptors with low‐lying lowest unoccupied molecular orbital (LUMO) energy levels are a crucial unit for donor–acceptor (D–A) π‐conjugated polymers (CPs) with the NIR‐II emission property, however, limited kinds of molecular skeletons are still available. Herein, D–A CPs involving fluorinated boron‐fused azobenzene complexes (BAz) with enhanced electron‐accepting properties are reported. Combination of fluorination at the azobenzene ligand and trifluoromethylation at the boron can effectively lower the LUMO energy level down to −4.42 eV, which is much lower than those of conventional strong electron‐acceptors. The synthesized series of CPs showed excellent absorption/fluorescence property in solution over a wide NIR range including NIR‐II. Furthermore, owing to the inherent solid‐state emissive property of the BAz skeleton, obvious NIR‐II fluorescence from the film (up to λFL=1213 nm) and the nanoparticle in water (λFL=1036 nm, brightness=up to 29 cm−1 M−1) were observed, proposing that our materials are applicable for developing next‐generation of NIR‐II luminescent materials.

NIR-II Absorption/Fluorescence of D-A π-Conjugated Polymers Composed of Strong Electron Acceptors Based on Boron-Fused Azobenzene Complexes.

Luminescence in the second near-infrared (NIR-II, 1,000-1,700 nm) window is beneficial especially for deep tissue imaging and optical sensors because of intrinsic high permeability through various media. Strong electron-acceptors with low-lying lowest unoccupied molecular orbital (LUMO) energy levels are a crucial unit for donor-acceptor (D-A) π-conjugated polymers (CPs) with the NIR-II emission property, however, limited kinds of molecular skeletons are still available. Herein, D-A CPs involving fluorinated boron-fused azobenzene complexes (BAz) with enhanced electron-accepting properties are reported. Combination of fluorination at the azobenzene ligand and trifluoromethylation at the boron can effectively lower the LUMO energy level down to -4.42 eV, which is much lower than those of conventional strong electron-acceptors. The synthesized series of CPs showed excellent absorption/fluorescence property in solution over a wide NIR range including NIR-II. Furthermore, owing to the inherent solid-state emissive property of the BAz skeleton, obvious NIR-II fluorescence from the film (up to λFL=1213 nm) and the nanoparticle in water (λFL=1036 nm, brightness=up to 29 cm-1 M-1) were observed, proposing that our materials are applicable for developing next-generation of NIR-II luminescent materials.

Aggregation-Induced Emission of Naphthalene Diimides: Effect of Chain Length on Liquid and Solid-Phase Emissive Properties.

The aggregation-induced emission (AIE) properties of a systematic series of naphthalene diimides (NDIs) varying the chain length at the imide positions have been studied. A solvophobic collapse of NDI units through the flash injection of THF NDI solutions in sonicating water triggers the formation of stable suspensions with enhanced fluorescence emissions. Shorter chains favor the π-π stacking of NDI units through H-aggregation producing a strong AIE effect showing remarkably high quantum yields that have not been observed for non core-substitued NDIs previously. On the other hand, NDIs functionalized with longer chains lead to more disordered domains where π-π stacking between NDI units is mainly given by J-aggregation unfavoring the AIE effect.

Halogenated Thienoacene Derivatives with Improved Emission Properties

Halogenated Thienoacene Derivatives with Improved Emission Properties

Optical, scintillation, and TSL properties of Ce-doped LiMgAlF6

Ce differently (0, 0.01, 0.1, 1, 2 and 5% with respect to Mg) doped LiMgAlF6 ceramics were synthesized by the spark plasma sintering (SPS) method. In photoluminescence (PL), emission bands appeared at 300 nm with 30 ns day time, and these emission properties were almost the same in scintillation under X-ray irradiation. Further, thermally stimulated luminescence (TSL) was observed after X-ray irradiation, and the primary glow peak temperature was 160 °C with a lower detection limit of ∼10 mGy.

Effect of High-Index Nanoparticles on the Emission Properties of a Dye-Doped Blue Phase Liquid Crystal

Effect of High-Index Nanoparticles on the Emission Properties of a Dye-Doped Blue Phase Liquid Crystal

Plasmon-emitter coupling in cytosine-rich hairpin DNA-templated silver nanoclusters: Thermal reversibility, white light emission, and dynamics inside live cells.

Bio-templated luminescent noble metal nanoclusters (NCs) have attracted great attention for their intriguing physicochemical properties. Continuous efforts are being made to prepare NCs with high fluorescence quantum yield (QY), good biocompatibility, and tunable emission properties for their widespread practical applications as new-generation environment-friendly photoluminescent materials in materials chemistry and biological systems. Herein, we explored the unique photophysical properties of silver nanoclusters (AgNCs) templated by cytosine-rich customized hairpin DNA. Our results indicate that a 36-nucleotide containing hairpin DNA with 20 cytosine (C20) in the loop can encapsulate photostable red-emitting AgNCs with an absolute QY of ∼24%. The luminescent properties in these DNA-templated AgNCs were found to be linked to the coupling between the surface plasmon and the emitter. These AgNCs exhibited excellent thermal sensitivity and were employed to produce high-quality white light emission with an impressive color rendering index of 90 in the presence of dansyl chloride. In addition, the as-prepared luminescent AgNCs possessing excellent biocompatibility can effectively mark the nuclear region of HeLa cells and can be employed as a luminescent probe to monitor the cellular dynamics at a single molecular resolution.