Organic materials with strong third-order nonlinear optical (NLO) responses are crucial for advancing laser protection technologies, such as optical limiters. However, achieving a high nonlinear absorption coefficient concurrently with an ultralow operational threshold remains a significant challenge. Herein, we report a combined experimental and theoretical study on the third-order NLO properties of a series of planar non-fused ring acceptors (NFRAs) featuring a unique A-D-A'-D-A architecture. Among them, the chlorinated derivative BDD2Cl exhibits superior performance, possessing a large nonlinear absorption coefficient (4.72 & times; 10-9 m/W) and an ultralow optical limiting threshold (0.44 J/cm2), outperforming its fluorinated analogue BDD2F and other counterparts. Femtosecond transient absorption and density functional theory calculations collaboratively unveil that this enhancement originates from its large dipole moment, second hyperpolarizability, and highly efficient excited-state absorption promoted by molecular planarity. This work not only identifies NFRAs as promising candidates for high-performance optical limiters but also establishes a structure-property paradigm, providing fundamental insights for the rational design of broadband organic NLO materials.

The rapid deployment of ultrashort pulsed lasers in biomedicine, spectroscopy, and micro/nanoprocessing has spurred demand for high-performance saturable absorbers (SAs). Despite rapid advancements, SAs remain limited by poor stability and...

Recently, 2D materials have emerged as a focal point in materials science research. Conventional 2D systems predominantly derive from layered van der Waals (vdW) crystals, where individual atomic planes are held together by weak interlayer interactions. However, groundbreaking developments have challenged this paradigm through the successful isolation of 2D materials from non‐van der Waals (non‐vdW) bulk crystals. Non‐vdW 2D materials resemble their vdW counterparts in atomically thin sheets with strong in‐plane covalent/ionic bonding but manifest distinguished structural characteristics, including large lattice distortions, abundant dangling bonds, and coordinatively unsaturated surface atoms. These intrinsic features endow them with enhanced surface reactivity and dynamic electronic states, which promote chemisorption of reactive species and accelerate interfacial charge transfer kinetics‐properties that are highly advantageous for energy applications. Nevertheless, the absence of weak interlayer vdW forces poses significant challenges in exfoliation processes, with fundamental mechanisms remaining poorly understood. This review systematically examines state‐of‐the‐art liquid‐phase exfoliation (LPE) methodologies for non‐vdW nanoflakes synthesis, critically analyzing their mechanistic foundations, process‐structure‐property relationships, and performance benchmarks in energy‐related technologies. Furthermore, key challenges are identified in improving nanoflakes quality, precise kinetic control, and advancing next‐generation artificial intelligence (AI) and smart energy systems, while proposing interdisciplinary strategies to advance this burgeoning field.

The use of photoreduction technology to convert carbon dioxide into high value-added fuels or chemicals is of great strategic significance although facing serious challenges. Herein, a new type of Cs3Bi2I9/In2S3 S-scheme heterojunction photocatalyst was prepared by self-assembling Cs3Bi2I9 quantum dots on the surface of tubular In2S3 derived from In-MOF, which showed excellent photocatalytic properties. Density functional theory calculations and experimental characterization reveal that the performance of the Cs3Bi2I9/In2S3 heterojunction is enhanced by the interface built-in electric field (IEF) that effectively drives charge separation and retains active sites with high redox capabilities. Notably, the Cs3Bi2I9/In2S3 (3.3%wt In) heterojunction catalyst demonstrated excellent CO2 photoreduction performance with CO selectivity of 85%, an electron consumption rate of 35.5 & micro;mol g-1 h-1 (10.4 & micro;mol g-1 h-1 for CO and 1.84 & micro;mol g-1 h-1 for CH4) that was three times of Cs3Bi2I9, and better than most reported Cs3Bi2I9-based catalysts. The high CO selectivity stems from stabilized *COOH intermediates and rapid CO desorption. Femtosecond transient absorption spectroscopy confirms that charge transfer from In2S3 to Cs3Bi2I9 QDs enables efficient charge separation, boosting photocatalytic CO2 reduction. This work provides a new strategy for designing high-performance Bi-based perovskite photocatalysts.

Two-dimensional transition metal dichalcogenides (2D TMDs) exhibit strong intrinsic third-order nonlinear optical responses, holding great potential for laser protection. Here, we demonstrate chemical vapor deposition (CVD) of large size MoSe2...

The escalating demand for reliable protection against high-fluence laser pulses across industrial, defense, and biomedical fields has driven intensive research into advanced optical limiting materials. A critical challenge remains the often-high operational threshold of such devices, which limits their sensitivity and practical deployment. Herein, we report the rational design and synthesis of a series of isostructural Ln3+-porphyrinic metal-organic frameworks (MOFs, Ln3+ = Gd, Tb, Er) that exhibit exceptional reverse saturable absorption (RSA). Remarkably, the erbium-based analogue (Er-TCPP) exhibits a giant third-order nonlinear absorption coefficient of 4.86 × 10-4 m/W and an ultralow starting threshold of 1.42 mJ/cm2 at 532 nm using the Z-scan technique. A synergistic mechanism is unveiled through combined femtosecond transient absorption spectroscopy and density functional theory (DFT + U) calculations. The giant third-order nonlinear response of Er-TCPP is likely driven by the combined effects of spin-orbit coupling and f-state-mediated excited-state interactions, together with the extensive electronic delocalization within the 18π-electron conjugated framework of the TCPP ligand, all of which collectively prolong excited-state carrier lifetimes and substantially enhance excited-state absorption. This study not only reports a state-of-the-art MOF with exceptional optical limiting performance but also establishes a general design principle based on targeted metal-ligand electronic synergy for developing advanced nonlinear optical materials.

Recently, halide perovskite X-ray detectors have demonstrated sensitivity orders of magnitude higher than that of state-of-the-art α-Se X-ray detectors, holding great potential to reshape the X-ray detector industry. However, the high dark current and severe baseline drift, caused by carrier injection and ion migration under external electric fields, hinder their practical use. In this context, perovskites are engineered as either semiconductor junctions or ferroelectrics to enable self-driven X-ray detection with ultralow dark current and negligible baseline drift, marking a cutting-edge development in the field. However, no efforts have been made to give a comprehensive review of perovskite self-driven X-ray detectors. This review aims to fill this research gap. It begins with a discussion of the basic physics underlying self-driven X-ray detection, followed by an analysis of its key performance metrics. Then, recent advances in self-driven X-ray detectors based on perovskite semiconductor junctions and ferroelectrics are critically reviewed, during which the remaining bottleneck issues are highlighted. Finally, it summarizes general guidelines drawn from previous endeavors and offers a perspective on the future development of perovskite self-driven X-ray detectors.

We developed a stereoselective synthesis strategy for α-fluoroacrylate-substituted β-lactams, utilizing an innovative acid-base synergistic regulation approach. This method employs a dioxane-mediated microreaction environment to spatially separate acidic and alkaline reagents, enabling precise control over cyclization and fluorination processes. This strategy enhances catalytic efficiency and addresses challenges in Pd-catalyzed reactions, offering a new paradigm for synthesizing fluorinated drug molecules amid acid-base complexities.

Space exploration is inseparable from advanced antiradiation materials with exceptional properties. Among these, nonlinear optical materials and devices, such as irradiation-resistant saturable absorbers (SAs), have garnered significant attention, particularly due to their critical role in integrated photonics for space use. This study presents a comprehensive evaluation of the space adaptability of two-dimensional (2D) W2N3 under simulated space radiation conditions. When subjected to 60Co γ-ray irradiation at doses exceeding 45 years of accumulation in a typical low-Earth orbit, W2N3 retained its robust third-order nonlinear saturable absorption across the visible- to near-infrared spectral range. Femtosecond transient absorption spectra offer a comprehensive view of the carrier dynamics of W2N3 before and after irradiation, delving into radiation effects and damage mechanisms that are otherwise elusive to conventional techniques. The synthesized W2N3 nanosheets were successfully employed as efficient SAs for Q-switched mode-locking in a Yb-doped fiber laser. The laser system operated at ∼1 μm NIR with high pulse energy and low saturation power, highlighting the remarkable potential of W2N3 for integration into lasers, modulators, and other photonic devices. Notably, the irradiated W2N3 demonstrated an identical mode-locking performance compared to its pristine counterpart. These findings provide valuable guidance for the rational design and screening of nonlinear optical materials capable of withstanding space radiation, offering significant implications for future space-based photonic applications.

The escalating demand for laser protection in military, industrial, and commercial sectors has intensified the pursuit for advanced optical limiting (OL) materials capable of safeguarding against high-intensity laser threats. Despite the progress, current OL materials are beset with challenges such as low linear transmittance, narrow operational bandwidths, and inadequate response speeds, which hinder their effectiveness in practical applications. In this work, an organometallic hybrid perovskite of 3-(fluoropyrrolidinium)MnCl3 demonstrated significant reverse saturable absorption properties, with an ultralow starting threshold of 9 mJ/cm2 and a substantial third-order nonlinear absorption coefficient of 4.1 × 10-5 m/W at 532 nm. Combined femtosecond transient absorption spectroscopy and density functional theory (DFT) calculations revealed that the strong nonlinear optical response originates from an excited-state absorption-dominated carrier dynamics process. This work establishes a novel material platform for developing high-sensitivity laser protection devices.

Atomically thick hexagonal boron nitride (h-BN) films have gained increasing interest, such as nanoelectronics and protection coatings. Chemical vapor deposition (CVD) has been proven to be an efficient method for synthesizing h-BN thin films, but its precursors are still limited. Here, it is reported that a novel and easily available precursor, surface-activated h-BN (As-hBN), with NH3/N2 as an additional nitrogen source is used for CVD growth of monolayer h-BN films on the Cu foils. The as-grown h-BN films can significantly enhance the anti-oxidation ability of copper. Molecular dynamics simulations reveal that the reactivity of the As-hBN precursors is attributed to the decomposition of unstable BO3 and O-terminal edges on the surface under H2 atmosphere. This method provides a more reliable approach for fabricating h-BN films.

In this experiment, five metal ions (K+, Mg2+, Al3+, Ga3+, and Sn4+) were utilized as copigments to investigate their copigmentation processes with cyanidin-3-O-glucoside (C3OG) in simulated fruit wine solutions. The color characteristics were analyzed using Glories and CIELAB methods, and the copigmentation effects were determined spectrophotometrically. Thermodynamic parameters, including the equilibrium constant (K) and standard Gibbs free energy (ΔG°), were calculated to comprehend the binding affinity between metal ions and C3OG. Ultra-fast femtosecond spectroscopy was employed to monitor the photoinduced electron transfer process between C3OG and cations. Theoretical calculations were also conducted to support experimental findings. The results revealed that the presence of metal ions significantly enhanced the color intensity of C3OG in simulated fruit wine solutions. Higher valency cations, particularly Sn4+, Ga3+, and Al3+, exhibited superior copigmentation effects, resulting in significant bathochromic and hyperchromic changes. Thermodynamic analysis confirmed that the interaction between C3OG and metal ions was spontaneous and exothermic. Ultra-fast femtosecond spectroscopy demonstrated that electron transfer from C3OG to metal ions occurred, with the efficiency of transfer being dependent on valency. Theoretical calculations corroborated the experimental results by highlighting the role of metal ions in stabilizing C3OG/metal complexes through electron transfer. The findings presented in this study contribute to a more comprehensive understanding of pigment/metal complexes and the underlying chemistry behind fruit wine color. Furthermore, it advances the theoretical foundation of copigmentation and broadens its applications in the beverage industry.

With the rapid development of space exploration, the detection of space neutron radiation is becoming increasingly important. The currently widely used Bonner sphere spectrometer have drawbacks such as large size and weight, as well as low fault tolerance, when detecting space neutron spectra. This paper describes in detail a new type of space neutron spectrometer (SNS), which has two different specifications to adapt to the directional and non-directional neutron field environment, and can measure the directional neutron energy spectrum. For the directed neutron field, SNS integrates 12 3 He thermal neutron counters (diameter 3 cm: 3, diameter 4 cm: 6, diameter 5 cm: 3) and uses cylindrical polyethylene as a moderator. For non-directed neutron fields, SNS integrates 9 3 He thermal neutron counters (diameter 3 cm: 4, diameter 4 cm: 3, diameter 5 cm: 2) located in a single structure made of polyethylene, boron-containing polyethylene and gadolinium. The device is capable of providing a strong directional response in the energy range of thermal neutrons up to 20 MeV, with little sensitivity to neutrons coming from directions other than the axis of the cylinder. The Monte Carlo transport code FLUKA was used to determine the final configuration of the instrument, including the arrangement, number, and position of thermal neutron counters. In addition, the response matrix of the instrument was calculated using FLUKA code. This device can replace traditional Bonner sphere spectrometer for measuring space neutrons, and it also provides reference value for downsized and lightweight neutron spectrometers on the ground.

N-centered radical-mediated remote C(sp3)-H functionalization via HAT processes has been successfully applied in the difunctionalization of alkenes, serving as an elegant and robust method to convert readily available alkenes into various functionalized molecules. However, HAT strategy-enabled difunctionalization of alkenes using electrophiles as functionalizing reagents remains underexplored. In this study, we report a nickel-catalyzed regioselective reductive three-component 1,2-alkylarylation of alkenes with O-oxalate hydroxamic acid esters and aryl iodides. This radical addition/cross-coupling cascade reaction involves amidyl radical-triggered intramolecular 1,5-HAT and nickel-catalyzed reductive coupling processes under mild reaction conditions with good coupling efficiency. Additionally, this approach can be extended to the reductive 1,2-alkylarylation of alkynes, providing an efficient method for the synthesis of multi-substituted alkenes from easily accessible starting materials.

A cascade phosphorylation cycloisomerization of readily accessible ynones and diphenylphosphine oxides facilitated by potassium phosphate is described, allowing for the straightforward synthesis of C4-phosphorylated quinoline scaffolds. The formation of a C-P bond and a C-N bond is achieved in a single procedure without the need for pre-assembled quinoline cores prior to phosphorylation. This transformation operates without the requirement for metals or oxidants and exhibits excellent compatibility with various functional groups. Furthermore, antimicrobial activity evaluation demonstrated that the synthesized C4-phosphorylated quinoline derivatives exhibited potent inhibitory activity against Staphylococcus aureus.

Radiocarbon and OSL dating are the two main approaches used to date aeolian deposits in arid central Asia (ACA). Previous results showed that, compared with OSL dating, the C-14 ages of loess deposits in ACA are underestimated when the loess age is beyond similar to 25 ka. However, the cause of this radiocarbon age underestimation has not been adequately addressed. In this study, we measured the C-14 ages of different dating materials, including pyrolysis volatile (Py-V), pyrolysis residue (Py-R), humin, and total organic carbon fractions from two loess sections in ACA (the Hoalin section in the western Pamir Mountains, and the TLD16 section in the northern Tianshan Mountains). The results show that different dating material yielded different C-14 ages for all the loess samples, and all the radiocarbon ages obtained are younger than their corresponding OSL ages. Based on these results, together with a regional comparison of 78 C-14 ages from ACA with their corresponding OSL ages, we propose that the C-14 age underestimation is mainly due to the contamination by the deep penetration of the extended root systems of the plants that grow in arid areas, whereas this effect is less significant in the summer monsoon-dominated Chinese Loess Plateau.

A chlorotrimethylsilane (TMSCl)-mediated cascade phosphorylation and cycloisomerization of enynones with diphenylphosphine oxides is presented. This methodology enables the highly selective synthesis of monophosphorylated 2H-pyrans and bisphosphorylated dihydropyrans through precise solvent-reagent stoichiometry control. The strategy demonstrated excellent functional group compatibility and high yields (up to 96%), providing facile access to structurally diverse phosphorylated heterocycles with potential applications in medicinal chemistry and materials science.

In this study, we conducted measurements of the independent fission cross-sections of 238U(n, f)97m+gNb, 238U(n, f)133gTe reactions and the cumulative cross section of 238U(n, f)130gSb reactions induced by neutron at energies around 14 MeV, i.e., 14.1 +/- 0.3, 14.5 +/- 0.3 and 14.7 +/- 0.3 MeV. The measurement results were obtained by the neutron activation method in combination with off-line gamma-ray spectrometry techniques. The neutron flux was monitored on line by the accompanying alpha-particle from T(d, n)4He reaction, and the neutron energies were determined by the cross-section ratio of 90Zr(n, 2n)8+gZr to 93Nb(n, 2n)92mNb reactions. The independent fission cross-sections of the fission reactions were obtained by subtracting the influence of precursor nuclei or excited states. The obtained results are as follows: for 238U(n, f)97m+gNb, the independent cross sections are 1.0 +/- 0.89, 0.98 +/- 0.85 and 0.78 +/- 0.70 mb at the specified neutron energy points. For 238U(n, f)133gTe, the independent fission cross-sections are 26.8 +/- 2.8, 27.7 +/- 2.9 and 20.5 +/- 2.3 mb, respectively, at the same neutron energy points. As for 238U(n, f)130gSb, the obtained cumulative fission cross-sections are 5.35 +/- 0.58, 5.05 +/- 0.53 and 4.03 +/- 0.44 mb, respectively, at the specified neutron energy points.

Herein, the palladium-catalyzed autotandem reaction of cyclopropyl alcohols with gem-dibromoolefins is described. This reaction system involves two distinct mechanistic processes, both efficiently catalyzed by the same palladium catalyst. This approach accommodates a wide substrate scope using readily available starting materials, offering a new and efficient method for synthesizing a series of β-pyrrolo[1,2-a]quinolinyl ketones.