Abstract Intense magnetic fields in the atmospheres of neutron stars render nontrivial angular dependence of intensity and polarization of soft X-ray emission originating from their surfaces. By tracking the complex electric field vector for each photon during its atmospheric transport and propagation in general relativistic and birefringent magnetospheres, our Monte Carlo simulation, named MAGTHOMSCATT , allows for capturing the complete polarization properties, including the intricate interplay between linearity and circularity. The new inclusion in MAGTHOMSCATT of quantum electrodynamical influences on polarization in the magnetosphere is presented. We simulate the pulsed and polarized X-ray emission from the outer layers of optically thick, fully ionized atmospheres of neutron stars, with a focus on the radiation emitted from extended polar caps of magnetars, which are the most highly magnetized neutron stars. Using the recent intensity pulse profile data for the magnetar 1RXS J1708–4009, we constrain the geometric parameters, namely, the angles between the magnetic axis and the observer’s viewing direction relative to the spin axis, as well as the sizes of emission regions. The distributions of these parameters and the best-fit configuration are provided. In addition, we discuss the important impacts of vacuum birefringence in the magnetosphere on increasing the linear polarization degree. A comparison with the case of a weakly magnetized neutron star, RX J0822.0–4300, is also discussed. Our simulation still needs further development, particularly to incorporate the vacuum resonance effect. Nevertheless, the formalism presented here can be employed to constrain geometric parameters for various types of neutron stars.

High-performance broadband near-infrared (NIR) phosphors are essential for the development of state-of-the-art NIR phosphor-converted light-emitting diodes (pc-LEDs). Herein, we report a novel Cr3+-doped Mg4GaSbO8 (MGSO) luminescent material based on an orthorhombic spinel-derived superstructure featuring multiple crystallographically distinct octahedral sites. By precisely modulating Cr3+ concentration, NIR emission with a remarkable tunability in full width at half-maximum from 100 to 308 nm is realized. Comprehensive spectroscopic analyses reveal three inequivalent Cr3+ emission centers (CrI, CrII, and CrIII) arising from selective substitution at Mg1, Mg2, and Mg3 octahedral sites with progressively weakened crystal fields. Increasing dopant concentration drives sequential site occupation and energy transfer among Cr3+ centers, leading to pronounced spectral redshift and ultrabroadband emission. The optimized MGSO:0.07Cr3+ shows a high quantum yield of 80.4% and solid thermal stability with 85.6% emission intensity retention at 373 K. At high doping levels (x = 0.20), the phosphor exhibits reduced thermal robustness but exceptional spectral broadening. Finally, MGSO:Cr3+ was integrated into NIR pc-LED prototypes, underscoring their potential applicability in nondestructive inspection and NIR spectroscopy.

Ytterbium-doped perovskite quantum dots show promise for optoelectronic and imaging applications, yet achieving efficient Yb incorporation remains challenging. We systematically optimized the synthesis parameters, including reaction temperature, precursor stoichiometry, OA/OAm ratio, and ligand content, which indeed strongly govern the Yb incorporation efficiency and emission intensity.

Abstract It is shown that for zincblende InGaN/GaN quantum wells produced by metal-organic vapor phase epitaxy, reducing the growth temperature from 740 °C to 684 °C tunes the emission from the blue to the orange region of the visible spectrum. The emission spectrum was found to be independent of the excitation density at each growth temperature, consistent with the quantum wells being free of significant internal polarisation fields. The spectrally integrated emission intensity at 300 K grows from 22 % to 34 % of its value at 11 K as the peak emission energy decreases from 2.75 eV to 2.0 eV; this reduction in thermal quenching as the emission energy decreases is attributed to a significant lessening of thermionic emission.

Structure-dependent luminescence of Tm3+-doped LaAlO3: from crystalline to amorphous states.

Abstract Upconversion nanoparticles (UCNPs) typically suffer from low emission intensity and aggregation during conventional annealing. Herein, we demonstrate molten salt annealing (MSA) as an effective strategy to enhance the luminescence of hydrothermally synthesized YPO4:15%Yb3+,2%Er3+ nanocrystals. Optimized MSA at 900°C for 2 hours yielded a ~700-fold emission enhancement over the hydrothermally synthesized nanocrystals and ~2.5-fold improvement relative to conventional annealing while preserving the rod-like morphology. These results identify MSA as a promising approach for producing brighter UCNPs while overcoming particle growth during thermal processing.

This study reports the precise synthesis of red-emitting gold–silver bimetallic nanoclusters (Au-AgNCs) via a one-pot hydrothermal method using thiolactic acid as both the ligand and reducing agent. The Au-AgNCs possess an average diameter of 1.85 nm and exhibit strong fluorescence emission at 687 nm. Furthermore, they display notable assembly-induced emission enhancement (AIEE) properties. Upon assembly with bovine serum albumin (BSA), their fluorescence quantum yield significantly increases from 2.50% to 7.78%. Then Au-AgNCs@BSA assembly was employed as a ratiometric fluorescence sensor for the detection of chlortetracycline (CTC). In the presence of CTC, the original red emission of the assembly at 687 nm remained stable, while a new blue emission emerged at 420 nm and intensified progressively with CTC concentration. The ratio of the two emission intensities (I420/I687) exhibited an excellent linear correlation with CTC concentration over the range of 0.10 to 15 μM, with a limit of detection (LOD) of 20 nM. Notably, the sensor demonstrated exceptional selectivity for CTC, showing negligible response to common interfering substances such as metal ions, anions, amino acids, and crucially, other tetracycline antibiotics (tetracycline, oxytetracycline, and doxycycline). The practical applicability of the sensor was validated through the determination of spiked CTC in real water samples, achieving satisfactory recovery rates. In conclusion, this work accomplishes two key objectives: the development of novel AIEE-active Au-Ag bimetallic nanoclusters and the design of an efficient ratiometric sensing strategy. This approach enables the highly selective and sensitive detection of CTC, offering a promising tool for environmental monitoring.

Lanthanide double perovskites (Ln-DPs) offer tunable emission and low toxicity, yet their weak crystal fields often fail to support efficient upconversion luminescence of lanthanide ions, limiting multimodal applications. While conventional dual-mode luminescence relies on complex core-shell architectures to mitigate cross-relaxation, we demonstrate here, in contrast, highly efficient dual-mode (upconversion and downshifting) emission from a simple bilayer heterostructure. An optimized thermal injection approach was employed to synthesize the heterostructure nanocomposites of Ln-DPs. And the incorporation of NaLnF4 not only enhanced the intrinsic luminescence and structural stability of the Ln-DPs via surface passivation, but also leveraged ion migration to provide an optimal crystal field for Er3+ ions, enabling tunable upconversion luminescence through its self-absorption. Subsequently, by regulating lanthanide ion concentration and spatial distribution, the red emission intensity of Er3+ ions was further improved by a factor of 13.23. This design offers a simple yet powerful strategy for achieving high-performance Ln-DPs light-emitting devices, highlighting their potential application in advanced optical coding and information encryption.

Site-selective luminescence in Ca-doped Sr2YNbO6:Eu3+ phosphors for high-color-purity red emission.

Construction and applications of photo-controlled fluorescent switches based on diarylethene modified red emission carbon dots.

Dual-state emission, stretchability, information encryption, and intrinsic mechanism based on a butterfly shaped molecule.

Emission based sensing of N-acetyl cysteine via silver equipped anthraquinone derivatives.

Design, synthesis, and applications of Naphthalimide-based Mechanofluorophores for multimodal security encryption and anti-counterfeiting technologies.

Quantifying the spatiotemporal characteristics and driving mechanisms of greenhouse gas emissions from the wastewater treatment sectors in Chinese cities.

Highly sensitive and selective fluorescence Nano-sensor for azathioprine determination using g-C3N4@Fe3O4@CoWO4 nanocomposite; box-Behnken design optimization.

Fluorescence sensing mechanism of contaminant Cu2+ in water by up-converting nanoparticles.

A new bis-acylhydrazone fluorescence sensor for the detection of ClO- with mechanochromic and thermochromic properties.

Carbon footprint characteristics and reduction strategies of the iron and steel industry: an LCA-based study of source, process, end-use and cleaner production applications.

Coreactant-accelerating electrochemiluminescence systems based on self-enhanced TiO2 inverse opal photonic crystals for ultrasensitive aptasensing of aflatoxin B1 in corn matrices with MoS2@Au/Pt nanocomposites as signal quencher.

Revealing the impact of multi-scale innovation networks on urban carbon emission intensity: Evidence from Chinese cities