Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_...Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_(2)O_(4)=oxalic acid,C_(6)N_(2)H_(11)=2-ethyl-4-methylimidazolium cation and C_(4)N_(2)H_(4)=pyrazine).Remarkably,crystal 2 exhibits an unprecedentedly large birefringence of 0.422 at 550 nm,which surpasses all commercial birefringent crystals.The formation of the directional hydrogen bonds between oxalate and planar pyrazine constituents facilitates the adoption of a planar configuration by oxalic units possessing large polarizability anisotropy(Δα=21.72).Whereas the distorted configuration of oxalate groups with a relatively small Δα of 13.95 induced by the non-coplanar arrangement of the imidazole planes of C_(6)N_(2)H_(11) leads to moderate birefringence(0.144@550 nm)for 1.Computational analyses reveal that the birefringent superiority of 2 originates from the synergistic effect of the π-conjugated oxalate and pyrazine units in a parallel arrangement directed by hydrogen bonds.This work breaks the record of birefringence in oxalates.It also develops a powerful hydrogen bond-directed strategy to modulate the configuration of oxalate groups,enabling its use as a tunable anisotropic structural unit for constructing birefringent crystals.展开更多
The effects of the high pressure die casting(HPDC)processes on porosity,microstructure,and mechanical properties of heat-treatment-free aluminum silicon(Al-Si)alloys have long been a focal point in automotive die-cast...The effects of the high pressure die casting(HPDC)processes on porosity,microstructure,and mechanical properties of heat-treatment-free aluminum silicon(Al-Si)alloys have long been a focal point in automotive die-casting research.In this work,the combined effect of shot sleeve materials and slow shot speeds on porosity,microstructure and mechanical properties of a newly designed HPDC Al-Si alloy was investigated.Results show that employing a ceramic shot sleeve or increasing the slow shot speed significantly reduces both the average size and area fraction of externally solidified crystals(ESCs),as well as the average pore size and volume fraction.When the slow shot speed is increased from 0.05 m·s^(-1)to 0.1 m·s^(-1),the pore volume fraction decreases by 10.2%in steel-shot-sleeve samples,compared to a substantial 67.1%reduction in ceramic-shot-sleeve samples.At a slow shot speed of 0.1 m·s^(-1),castings produced with a ceramic shot sleeve exhibit superior mechanical properties:8.3%higher yield strength,17.4%greater tensile strength,and an 81.4%improvement in elongation,relative to those from a steel shot sleeve.These findings provide valuable insights for minimizing porosity and coarse ESCs in die castings,offering promising potential for broader industrial applications.展开更多
Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior a...Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior and mechanical property of molecular crystals simultaneously via supramolecular salt strategy is rarely reported,which is very important to improve their photophysical behavior and softness for the fabrication of flexible light-emitting device.Herein,supramolecular salt approach has been successfully applied to synthesize two elastic organic fluorescent crystals(CMOH-Py-Cl and CMOH-Py-Br)derived from non-emissive and brittle pyridine-substituted coumarin derivative(CMOH-Py).Their elastic properties can be attributed to the prevalent presence of numerous weak interactions introduced by halogen atoms,which are beneficial to the absorption and release of mechanical energy.Furthermore,density functional theory(DFT)calculations demonstrated a narrowing of the HOMO-LUMO energy gaps from CMOH-Py to CMOH-Py-Cl/CMOH-Py-Br via supramolecular salt approach.Finally,the application of flexible crystal materials in the field of optical waveguides has been investigated.The transformation of crystals in terms of photophysical and mechanical properties,achieved by the supramolecular salt approach,offers novel insights into the design and construction of flexible crystalline materials,providing a new path for the development of next-generation smart materials.展开更多
The growing demand for personalized health care,smart wearables,and advanced environmental monitoring has spurred the development of multifunctional materials that combine flexibility,environmental adaptability,and di...The growing demand for personalized health care,smart wearables,and advanced environmental monitoring has spurred the development of multifunctional materials that combine flexibility,environmental adaptability,and diverse functionalities.However,conventional materials often failed to integrate these attributes simultaneously,hindering their applicability in next-generation technologies.Here,we present an organic-inorganic hybrid crystalline material with a unique sandwich-like architecture,in which a flexible organic crystal core is encased by reduced graphene oxide(rGO)and thermoplastic polyurethane(TPU).This strategic integration endows the material with fluorescence,cryogenic flexibility,and electrical conductivity,while also enabling dual sensing and actuation capabilities.The rGO layer facilitates real-time humidity(25-90%RH)and temperature(25-180℃)sensing through environmental interactions,whereas the differential thermal expansion between TPU and the flexible crystal core drives efficient photothermal actuation at-150℃for advanced thermal regulation.The hybrid material exhibits stable performance under extreme conditions,making it a promising candidate for biomedical monitoring,flexible electronics,and energy applications.This work establishes hybrid crystalline materials as versatile and scalable platforms for addressing complex technological demands,paving the way for their application in next-generation multifunctional devices.展开更多
Temperature-dependent resistivity,upper critical field H_(c2)and its anisotropy in overdoped superconducting Ba_(1-x)K_x Fe_2As_2(x=0.6-1)single crystals have been measured in steady magnetic fields up to 44 T and low...Temperature-dependent resistivity,upper critical field H_(c2)and its anisotropy in overdoped superconducting Ba_(1-x)K_x Fe_2As_2(x=0.6-1)single crystals have been measured in steady magnetic fields up to 44 T and low temperatures down to 0.4 K.Analysis using both the quadratic term and power-law fitting demonstrates that the in-plane resistivityρ_(ab)(T)progressively approaches the Fermi-liquid T~2behavior with increasing K doping and reaches a saturation plateau at x≈0.8.The temperature dependence of both H_(c2)^(ab)and H^(c)_(c2)follows the Werthamer-Helfand-Hohenberg model,incorporating orbital and spin paramagnetic effects.For x≤0.8,the orbital effect dominates for H ab,while the Pauli paramagnetic effect prevails for H c.For x>0.8,the Pauli paramagnetic effect becomes dominant in both crystallographic directions.The anisotropy of H_(c2)(0)exhibits a discontinuity in its dependence on K doping concentration with a significant enhancement at x=0.8 and a maximum at x=0.9.These experimental results indicate that the electron correlation effect is enhanced in the heavily overdoped Ba_(1-x)K_(x)Fe_(2)As_(2)system where the underlying symmetries are broken due to the Fermi surface reconstruction before x=0.9.展开更多
Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled t...Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.展开更多
Accurately predicting the synthesizability of inorganic crystal materials serves as a pivotal tool for the efficient screening of viable candidates,substantially reducing the costs associated with extensive experiment...Accurately predicting the synthesizability of inorganic crystal materials serves as a pivotal tool for the efficient screening of viable candidates,substantially reducing the costs associated with extensive experimental trial-and-error processes.However,existing methods,limited by static structural descriptors such as chemical composition and lattice parameters,fail to account for atomic vibrations,which may introduce spurious correlations and undermine predictive reliability.Here,we propose a deep learning model termed integrating graph and dynamical stability(IGDS)for predicting the synthesizability of inorganic crystals.IGDS employs graph representation learning to construct crystal graphs that precisely capture the static structures of crystals and integrates phonon spectral features extracted from pre-trained machine learning interatomic potentials to represent their dynamic properties.Our model exhibits outstanding performance in predicting the synthesizability of low-energy unsynthesizable crystals across 41 material systems,achieving precision and recall values of 0.916/0.863 for ternary compounds.By capturing both static structural descriptors and dynamic features,IGDS provides a physics-informed method for predicting the synthesizability of inorganic crystals.This approach bridges the gap between theoretical design concepts and their practical implementation,thereby streamlining the development cycle of new materials and enhancing overall research efficiency.展开更多
Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operati...Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operational costs,particularly for hydrocarbons with high boiling points or strong host-vip interactions[2].This is the same case in the newly-developed macrocyclebased crystalline adsorbents,namely nonporous adaptive crystals(NACs).To address these challenges,a recent study published in Angewandte Chemie International Edition by Jie,Ma,and co-workers reported an innovative molecular-"squeeze"triggered desorption mechanism in NACs[3-5].Specifically,ethyl acetate(EA)triggers vip desorption without penetrating the crystal pores or voids.Instead,EA molecules interact with the crystal surface through supramolecular forces,causing the adaptive closure of voids and the subsequent release of vip molecules.Unlike conventional sponges that rely on mechanical squeeze to deform themselves in the bulk for vip release,these macrocycle crystals undergo structural deformation at the molecular level and condensed phase when exposed to vaporized molecules.Because of the similar behavior between sponges and such NACs,the authors name them as sponge-likemacrocyclecrystals.展开更多
Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, includin...Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, including research history, significant achievements, and important applications by highlighting the most recent progress in research. Challenges for the development of functional materials are discussed and possible directions for development are proposed by focusing on potential strengths of these materials.展开更多
High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress aro...High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.展开更多
This study reports the synthesis of oleic acid sterol ester with liquid crystalline properties and its enhanced stability and UV-blocking performance through microencapsulation.Oleic acid sterol ester was synthesized ...This study reports the synthesis of oleic acid sterol ester with liquid crystalline properties and its enhanced stability and UV-blocking performance through microencapsulation.Oleic acid sterol ester was synthesized via the esterification of phytosterol and oleic acid,whose structure was characterized using Fourier-transform infrared spectroscopy(FTIR)and mass spectrometry(MS).Its liquid crystalline behavior was confirmed via the polarized optical microscopy(POM),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC),wide-angle X-ray scattering(WAXS),and small-angle X-ray scattering(SAXS).UV absorption tests were conducted to assess the UV-blocking performance of the oleic acid sterol ester liquid crystals.To improve the stability of its liquid crystalline structure,the oleic acid sterol ester was encapsulated into microcapsules through the emulsion polymerization.SPF measurements were performed on the sunscreen formulations containing liquid crystal microcapsules.The oleic acid sterol ester displayed cholesteric liquid crystalline behavior and strong UVA absorption,which indicates its suitability as a natural UV absorber.Microencapsulation further enhanced its stability and UV-blocking properties.SPF testing showed that the formulations with microcapsules achieved an SPF value of 7.01,which surpasses the nano titanium dioxide(SPF=6.23)and significantly outperform the unencapsulated liquid crystal formulations(SPF=2.65).This study highlights the potential of microencapsulated oleic acid sterol ester as a novel UV absorber in the sunscreen formulations,offers the enhanced stability and effective UV protection,and showcases its application potential in the innovative cosmetic products.展开更多
In order to improVe the pyroelectric properties of TGS crystals,the different dopants were selected according to crystal chemistry principle and pyroelectric effect of molecules and ionic group to grow new modified TG...In order to improVe the pyroelectric properties of TGS crystals,the different dopants were selected according to crystal chemistry principle and pyroelectric effect of molecules and ionic group to grow new modified TGS crystals. The experimental results show that some dopants can improve the pyroelectric proPerties of TGS crystals.展开更多
Tamm plasmon polaritons(TPPs)are localized photonic states at the interface between a metal layer and one-dimensional(1D)photonic crystal substrate.Unlike surface plasmon polaritons(SPPs),TPPs can be excited by both t...Tamm plasmon polaritons(TPPs)are localized photonic states at the interface between a metal layer and one-dimensional(1D)photonic crystal substrate.Unlike surface plasmon polaritons(SPPs),TPPs can be excited by both transverse magnetic and electric waves without requiring additional coupling optics.TPPs offer robust color filtering,making them ideal for applications such as complementary metal oxide semiconductor(CMOS)image detectors.However,obtaining a large-area,reversible,and reconfigurable filter remains challenging.This study demonstrates a dynamically reconfigurable reflective color filter by integrating an ultrathin antimony trisulfide(Sb_(2)S_(3))layer with Tamm plasmonic photonic crystals.Reconfigurable tuning was achieved by inducing Sb_(2)S_(3) crystallization and reamorphization via thermal and optical activation,respectively.The material exhibited good stability after multiple switching cycles.The reflectance spectrum can be tuned across the visible range,with a shift of approximately 50 nm by switching Sb_(2)S_(3) between its amorphous and crystalline phases.This phase transition is nonvolatile and substantially minimizes the energy consumption,enhancing efficiency for practical applications.Tamm plasmonic photonic crystals are low-cost and large-scale production,offering a platform for compact color display systems and customizable photonic crystal filters for realistic system integration.展开更多
The unique structure and exceptional properties of two-dimensional(2D)materials offer significant potential for transformative advancements in semiconductor industry.Similar to the reliance on wafer-scale single-cryst...The unique structure and exceptional properties of two-dimensional(2D)materials offer significant potential for transformative advancements in semiconductor industry.Similar to the reliance on wafer-scale single-crystal ingots for silicon-based chips,practical applications of 2D materials at the chip level need large-scale,high-quality production of 2D single crystals.Over the past two decades,the size of 2D single-crystals has been improved to wafer or meter scale,where the nucleation control during the growth process is particularly important.Therefore,it is essential to conduct a comprehensive review of nucleation control to gain fundamental insights into the growth of 2D single-crystal materials.This review mainly focuses on two aspects:controlling nucleation density to enable the growth from a single nucleus,and controlling nucleation position to achieve the unidirectionally aligned islands and subsequent seamless stitching.Finally,we provide an overview and forecast of the strategic pathways for emerging 2D materials.展开更多
Although three-dimensional metal halide perovskites are promising candidates for direct X-ray detection,the ion migration of perovskites seriously affects the detector stability.Herein,face-/edge-shared 3D heterometal...Although three-dimensional metal halide perovskites are promising candidates for direct X-ray detection,the ion migration of perovskites seriously affects the detector stability.Herein,face-/edge-shared 3D heterometallic glycinate hybrid perovskitoid Pb_(2)CuGly_(2)X_(4)(Gly=-O_(2)C-CH_(2)-NH_(2);X=Cl,Br)single crystals(SCs),in which the adjacent lead halide layers are linked by large-sized Cu(Gly)_(2)pillars,are synthesized in water.The Cu(Gly)_(2)pillars in combination with face-/edge-shared inorganic skeleton are found able to synergistically suppress the ion migration,delivering a high ion migration activation energy(Ea)of 1.06 eV.The Pb_(2)CuGly_(2)Cl_(4)SC X-ray detector displays extremely low dark current drift of 1.20×10^(-9)nA mm^(-1)s^(-1)V^(-1)under high electric field(120 V mm^(-1))and continuous X-ray irradiation(2.86 Gy),and a high sensitivity of 9,250μC Gy^(-1)cm^(-2)is also achieved.More excitingly,the Pb_(2)CuGly_(2)Cl_(4)nanocrystal can be easily dispersed in water and directly blade-coated on thin-film transistor(TFT)array substrate,and the obtained Pb_(2)CuGly_(2)Cl_(4)-based TFT array detector offers an X-ray imaging capability with spatial resolution of 2.2 lp mm^(-1).展开更多
We study the topological states(TSs)of all-dielectric honeycomb valley photonic crystals(VPCs).Breaking the space inversion symmetry of the honeycomb lattice by varying the filling ratio of materials for circular ring...We study the topological states(TSs)of all-dielectric honeycomb valley photonic crystals(VPCs).Breaking the space inversion symmetry of the honeycomb lattice by varying the filling ratio of materials for circular ring dielectric columns in the unit cell,which triggers topological phase transitions and thus achieves topological edge states(TESs)and topological corner states(TCSs).The results demonstrate that this structure has efficient photon transmission characteristics and anti-scattering robustness.In particular,we have found that changing the type of edge splicing between VPCs with different topological properties produces a change in the frequency of TCSs,and then based on this phenomenon,we have used a new method of adjusting only the type of edge splicing of the structure to design a novel TCSs combiner that can integrate four TCSs with different frequencies.This work not only expands the variety and number of unexplored TCSs that may exist in a fixed photonic band gap and can be rationalized to be selectively excited in the fixed configuration.Our study provides a feasible pathway for the design of integrated optical devices in which multiple TSs coexist in a single photonic system.展开更多
The separation of alicyclic ketones and alicyclic alcohols is one of the challenges in the field of petrochemical industry. However, traditional separation methods suffer from excessive energy consumption,complicated ...The separation of alicyclic ketones and alicyclic alcohols is one of the challenges in the field of petrochemical industry. However, traditional separation methods suffer from excessive energy consumption,complicated operation, and unsatisfactory separation efficiency for substances with similar boiling points.Herein, we offer an innovative method for the separation of alicyclic ketones and alicyclic alcohols employing nonporous adaptive crystals(NACs) of perethylated pillar[5]arene(EtP5) and perethylated pillar[6]arene(Et P6). NACs of EtP5 cannot adsorb either alicyclic ketones or alicyclic alcohols because of the small cavity size of Et P5. By contrast, NACs of Et P6 can separate cyclopentanone from the vapor mixture of cyclopentanone/cyclopentanol(v:v = 1:1) and cyclohexanone from the vapor mixture of cyclohexanone/cyclohexanol(v:v = 1:1) with purities of 99.1% and 100%, respectively. Density functional theory calculations show that the selectivity comes from the thermodynamic stability of the newly formed crystal structure after adsorption of the preferred vip molecule. Moreover, NACs of Et P6 can be reused without losing selectivity and performance.展开更多
Chiral topological semimetals hosting multifold fermions and exotic surface states represent a frontier in topological materials research. Among them, noncentrosymmetric cubic B20 compounds—notably transitionmetal si...Chiral topological semimetals hosting multifold fermions and exotic surface states represent a frontier in topological materials research. Among them, noncentrosymmetric cubic B20 compounds—notably transitionmetal silicides and germanides—offer a unique platform for realizing symmetry-protected topological phases and unconventional optoelectronic responses. Here, we report the physical properties of Rh Ge and Co Ge single crystals with B20 structure in detail. Transport measurements revea metallic behavior with characteristic Fermi-liquid scaling at low temperatures, while magnetization results confirm paramagnetism in both compounds. In addition,both materials exhibit low carrier concentrations with small electronic specific heat coefficients, indicating their semimetal feature with weak electronic correlations. Such high-quality Co Ge and Rh Ge single crystals provide a material platform to explore the evolution of multifold fermions and the instability of helicoid-arc surface states with spin–orbit coupling and surface environment in B20 material systems.展开更多
Advances in controllable growth of ultra thin two-dimensional molecular crystals(2DMCs)or even monolayer molecular crystals(MMCs)propelled their application in high-performance,high-sensitivity,lowcontact-resistance o...Advances in controllable growth of ultra thin two-dimensional molecular crystals(2DMCs)or even monolayer molecular crystals(MMCs)propelled their application in high-performance,high-sensitivity,lowcontact-resistance optoelectronic devices.However,the rational molecular design strategies for materials prone to grow into ultrathin 2DMC or MMC have rarely been addressed.Here,systematically tailoring theπ-conjugation and alkyl chain types of asymmetric anthracene derivatives,2DMCs and even MMCs were obtained under the synergetic regulation of inter-and intralayer interactions.High-quality MMCs were obtained for SAP-C6 by traditional physical vapor transport technique(PVT),and corresponding organic field-effect transistors(OFETs)exhibited high mobility of 3.22 cm^(2)V^(-1)s^(-1).In addition,band-like charge transport with low activation energy was achieved by SAP-C6 MMC-OFETs.Furthermore,the SAPC6 MMC-based device exhibits excellent thermal stability,retaining~70%of its initial performance at 140℃in air,which is the first report on the thermal stability of MMC devices.This research highlights the potential of alkyl-substituted asymmetric molecules as a design strategy to achieve ultrathin 2DMC or MMC growth,and improve the mobility and thermal stability in OFETs.展开更多
Realizing the valley Hall effect by breaking the spatial inversion symmetry of photonic systems has become a cutting-edge field of micro-nano-optics,since the valley degree of freedom was introduced into photonic syst...Realizing the valley Hall effect by breaking the spatial inversion symmetry of photonic systems has become a cutting-edge field of micro-nano-optics,since the valley degree of freedom was introduced into photonic system.Various novel devices based on the domain walls of the valley photonic crystals have also been demonstrated.In this article,we investigate the variation of edge states by the modulation of refractive index within the domain walls,and the geometric difference between the dielectric columns of the sublattices.Straight photonic crystal waveguides with three types of domain walls(bearded,zigzag,armchair)are constructed.Simulation results show that the creation of a double-edge state in the band diagram results in two windows of stable transmission in tunable bands.Our findings might have significant implications in the field of novel optical devices.展开更多
基金supported by the National Natural Science Foundation of China(22361021,22261023)。
文摘Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_(2)O_(4)=oxalic acid,C_(6)N_(2)H_(11)=2-ethyl-4-methylimidazolium cation and C_(4)N_(2)H_(4)=pyrazine).Remarkably,crystal 2 exhibits an unprecedentedly large birefringence of 0.422 at 550 nm,which surpasses all commercial birefringent crystals.The formation of the directional hydrogen bonds between oxalate and planar pyrazine constituents facilitates the adoption of a planar configuration by oxalic units possessing large polarizability anisotropy(Δα=21.72).Whereas the distorted configuration of oxalate groups with a relatively small Δα of 13.95 induced by the non-coplanar arrangement of the imidazole planes of C_(6)N_(2)H_(11) leads to moderate birefringence(0.144@550 nm)for 1.Computational analyses reveal that the birefringent superiority of 2 originates from the synergistic effect of the π-conjugated oxalate and pyrazine units in a parallel arrangement directed by hydrogen bonds.This work breaks the record of birefringence in oxalates.It also develops a powerful hydrogen bond-directed strategy to modulate the configuration of oxalate groups,enabling its use as a tunable anisotropic structural unit for constructing birefringent crystals.
基金the National Key Research and Development Program of China(Grant No.2022YFB3404201)the National Natural Science Foundation of China(Grant Nos.52175335,52405342)+1 种基金the Natural Science Foundation Joint Foundation of Liaoning province(Grant No.2023-B SB A-108)the Fundamental Research Funds for the Central Universities(Grant No.N2402005)。
文摘The effects of the high pressure die casting(HPDC)processes on porosity,microstructure,and mechanical properties of heat-treatment-free aluminum silicon(Al-Si)alloys have long been a focal point in automotive die-casting research.In this work,the combined effect of shot sleeve materials and slow shot speeds on porosity,microstructure and mechanical properties of a newly designed HPDC Al-Si alloy was investigated.Results show that employing a ceramic shot sleeve or increasing the slow shot speed significantly reduces both the average size and area fraction of externally solidified crystals(ESCs),as well as the average pore size and volume fraction.When the slow shot speed is increased from 0.05 m·s^(-1)to 0.1 m·s^(-1),the pore volume fraction decreases by 10.2%in steel-shot-sleeve samples,compared to a substantial 67.1%reduction in ceramic-shot-sleeve samples.At a slow shot speed of 0.1 m·s^(-1),castings produced with a ceramic shot sleeve exhibit superior mechanical properties:8.3%higher yield strength,17.4%greater tensile strength,and an 81.4%improvement in elongation,relative to those from a steel shot sleeve.These findings provide valuable insights for minimizing porosity and coarse ESCs in die castings,offering promising potential for broader industrial applications.
基金supported by the National Natural Science Foundation of China(Nos.22205105,61874053,22075136)National Key Basic Research Program of China(No.2020YFA0709900)Jiangsu Provincial Postgraduate Scientific Research Innovation Program(No.KYCX24_1649).
文摘Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior and mechanical property of molecular crystals simultaneously via supramolecular salt strategy is rarely reported,which is very important to improve their photophysical behavior and softness for the fabrication of flexible light-emitting device.Herein,supramolecular salt approach has been successfully applied to synthesize two elastic organic fluorescent crystals(CMOH-Py-Cl and CMOH-Py-Br)derived from non-emissive and brittle pyridine-substituted coumarin derivative(CMOH-Py).Their elastic properties can be attributed to the prevalent presence of numerous weak interactions introduced by halogen atoms,which are beneficial to the absorption and release of mechanical energy.Furthermore,density functional theory(DFT)calculations demonstrated a narrowing of the HOMO-LUMO energy gaps from CMOH-Py to CMOH-Py-Cl/CMOH-Py-Br via supramolecular salt approach.Finally,the application of flexible crystal materials in the field of optical waveguides has been investigated.The transformation of crystals in terms of photophysical and mechanical properties,achieved by the supramolecular salt approach,offers novel insights into the design and construction of flexible crystalline materials,providing a new path for the development of next-generation smart materials.
基金support from the National Natural Science Foundation of China(52373181 and 52173164)the Natural Science Foundation of Jilin Province(20250102120JC and 20230101038JC)+1 种基金the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZB20240259)the Project funded by China Postdoctoral Science Foundation(2024M761121 and 2025T180139).
文摘The growing demand for personalized health care,smart wearables,and advanced environmental monitoring has spurred the development of multifunctional materials that combine flexibility,environmental adaptability,and diverse functionalities.However,conventional materials often failed to integrate these attributes simultaneously,hindering their applicability in next-generation technologies.Here,we present an organic-inorganic hybrid crystalline material with a unique sandwich-like architecture,in which a flexible organic crystal core is encased by reduced graphene oxide(rGO)and thermoplastic polyurethane(TPU).This strategic integration endows the material with fluorescence,cryogenic flexibility,and electrical conductivity,while also enabling dual sensing and actuation capabilities.The rGO layer facilitates real-time humidity(25-90%RH)and temperature(25-180℃)sensing through environmental interactions,whereas the differential thermal expansion between TPU and the flexible crystal core drives efficient photothermal actuation at-150℃for advanced thermal regulation.The hybrid material exhibits stable performance under extreme conditions,making it a promising candidate for biomedical monitoring,flexible electronics,and energy applications.This work establishes hybrid crystalline materials as versatile and scalable platforms for addressing complex technological demands,paving the way for their application in next-generation multifunctional devices.
基金supported by the National Key Research and Development Program of China(Grant Nos.2024YFA1611100,2023YFA1406100,and 2018YFA0704201)the Systematic Fundamental Research Program Leveraging Major Scientific and Technological Infrastructure,Chinese Academy of Sciences(Grant No.JZHKYPT-2021-08)+1 种基金the National Natural Science Foundation of China(Grant Nos.11704385,11874359,and 12274444)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB25000000)。
文摘Temperature-dependent resistivity,upper critical field H_(c2)and its anisotropy in overdoped superconducting Ba_(1-x)K_x Fe_2As_2(x=0.6-1)single crystals have been measured in steady magnetic fields up to 44 T and low temperatures down to 0.4 K.Analysis using both the quadratic term and power-law fitting demonstrates that the in-plane resistivityρ_(ab)(T)progressively approaches the Fermi-liquid T~2behavior with increasing K doping and reaches a saturation plateau at x≈0.8.The temperature dependence of both H_(c2)^(ab)and H^(c)_(c2)follows the Werthamer-Helfand-Hohenberg model,incorporating orbital and spin paramagnetic effects.For x≤0.8,the orbital effect dominates for H ab,while the Pauli paramagnetic effect prevails for H c.For x>0.8,the Pauli paramagnetic effect becomes dominant in both crystallographic directions.The anisotropy of H_(c2)(0)exhibits a discontinuity in its dependence on K doping concentration with a significant enhancement at x=0.8 and a maximum at x=0.9.These experimental results indicate that the electron correlation effect is enhanced in the heavily overdoped Ba_(1-x)K_(x)Fe_(2)As_(2)system where the underlying symmetries are broken due to the Fermi surface reconstruction before x=0.9.
基金supported by the Research Project on Strengthening the Construction of an Important Ecological Security Barrier in Northern China by Higher Education Institutions in the Inner Mongolia Autonomous Region(STAQZX202313)the Inner Mongolia Autonomous Region Education Science‘14th Five-Year Plan’2024 Annual Research Project(NGJGH2024635).
文摘Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.
文摘Accurately predicting the synthesizability of inorganic crystal materials serves as a pivotal tool for the efficient screening of viable candidates,substantially reducing the costs associated with extensive experimental trial-and-error processes.However,existing methods,limited by static structural descriptors such as chemical composition and lattice parameters,fail to account for atomic vibrations,which may introduce spurious correlations and undermine predictive reliability.Here,we propose a deep learning model termed integrating graph and dynamical stability(IGDS)for predicting the synthesizability of inorganic crystals.IGDS employs graph representation learning to construct crystal graphs that precisely capture the static structures of crystals and integrates phonon spectral features extracted from pre-trained machine learning interatomic potentials to represent their dynamic properties.Our model exhibits outstanding performance in predicting the synthesizability of low-energy unsynthesizable crystals across 41 material systems,achieving precision and recall values of 0.916/0.863 for ternary compounds.By capturing both static structural descriptors and dynamic features,IGDS provides a physics-informed method for predicting the synthesizability of inorganic crystals.This approach bridges the gap between theoretical design concepts and their practical implementation,thereby streamlining the development cycle of new materials and enhancing overall research efficiency.
基金the Natural Science Foundation of Jiangsu Province(No.BK20240679)National Natural Science Foundation of China(No.22101134)are greatly acknowledged。
文摘Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operational costs,particularly for hydrocarbons with high boiling points or strong host-vip interactions[2].This is the same case in the newly-developed macrocyclebased crystalline adsorbents,namely nonporous adaptive crystals(NACs).To address these challenges,a recent study published in Angewandte Chemie International Edition by Jie,Ma,and co-workers reported an innovative molecular-"squeeze"triggered desorption mechanism in NACs[3-5].Specifically,ethyl acetate(EA)triggers vip desorption without penetrating the crystal pores or voids.Instead,EA molecules interact with the crystal surface through supramolecular forces,causing the adaptive closure of voids and the subsequent release of vip molecules.Unlike conventional sponges that rely on mechanical squeeze to deform themselves in the bulk for vip release,these macrocycle crystals undergo structural deformation at the molecular level and condensed phase when exposed to vaporized molecules.Because of the similar behavior between sponges and such NACs,the authors name them as sponge-likemacrocyclecrystals.
文摘Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, including research history, significant achievements, and important applications by highlighting the most recent progress in research. Challenges for the development of functional materials are discussed and possible directions for development are proposed by focusing on potential strengths of these materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52175284 and 52474396)the National Key Research and Development Program of China(No.2022YFB3404201)。
文摘High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.
文摘This study reports the synthesis of oleic acid sterol ester with liquid crystalline properties and its enhanced stability and UV-blocking performance through microencapsulation.Oleic acid sterol ester was synthesized via the esterification of phytosterol and oleic acid,whose structure was characterized using Fourier-transform infrared spectroscopy(FTIR)and mass spectrometry(MS).Its liquid crystalline behavior was confirmed via the polarized optical microscopy(POM),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC),wide-angle X-ray scattering(WAXS),and small-angle X-ray scattering(SAXS).UV absorption tests were conducted to assess the UV-blocking performance of the oleic acid sterol ester liquid crystals.To improve the stability of its liquid crystalline structure,the oleic acid sterol ester was encapsulated into microcapsules through the emulsion polymerization.SPF measurements were performed on the sunscreen formulations containing liquid crystal microcapsules.The oleic acid sterol ester displayed cholesteric liquid crystalline behavior and strong UVA absorption,which indicates its suitability as a natural UV absorber.Microencapsulation further enhanced its stability and UV-blocking properties.SPF testing showed that the formulations with microcapsules achieved an SPF value of 7.01,which surpasses the nano titanium dioxide(SPF=6.23)and significantly outperform the unencapsulated liquid crystal formulations(SPF=2.65).This study highlights the potential of microencapsulated oleic acid sterol ester as a novel UV absorber in the sunscreen formulations,offers the enhanced stability and effective UV protection,and showcases its application potential in the innovative cosmetic products.
文摘In order to improVe the pyroelectric properties of TGS crystals,the different dopants were selected according to crystal chemistry principle and pyroelectric effect of molecules and ionic group to grow new modified TGS crystals. The experimental results show that some dopants can improve the pyroelectric proPerties of TGS crystals.
文摘Tamm plasmon polaritons(TPPs)are localized photonic states at the interface between a metal layer and one-dimensional(1D)photonic crystal substrate.Unlike surface plasmon polaritons(SPPs),TPPs can be excited by both transverse magnetic and electric waves without requiring additional coupling optics.TPPs offer robust color filtering,making them ideal for applications such as complementary metal oxide semiconductor(CMOS)image detectors.However,obtaining a large-area,reversible,and reconfigurable filter remains challenging.This study demonstrates a dynamically reconfigurable reflective color filter by integrating an ultrathin antimony trisulfide(Sb_(2)S_(3))layer with Tamm plasmonic photonic crystals.Reconfigurable tuning was achieved by inducing Sb_(2)S_(3) crystallization and reamorphization via thermal and optical activation,respectively.The material exhibited good stability after multiple switching cycles.The reflectance spectrum can be tuned across the visible range,with a shift of approximately 50 nm by switching Sb_(2)S_(3) between its amorphous and crystalline phases.This phase transition is nonvolatile and substantially minimizes the energy consumption,enhancing efficiency for practical applications.Tamm plasmonic photonic crystals are low-cost and large-scale production,offering a platform for compact color display systems and customizable photonic crystal filters for realistic system integration.
基金supported by the National Natural Science Foundation of China(12322406,12404208)the National Key R&D Program of China(2022YFA1403503)+2 种基金China Postdoctoral Science Foundation(2024M750970)the Science and Technology Program of Guangzhou(SL2024A04J00033)the Scientific Research lnnovation Project of Graduate School of South China Normal University.
文摘The unique structure and exceptional properties of two-dimensional(2D)materials offer significant potential for transformative advancements in semiconductor industry.Similar to the reliance on wafer-scale single-crystal ingots for silicon-based chips,practical applications of 2D materials at the chip level need large-scale,high-quality production of 2D single crystals.Over the past two decades,the size of 2D single-crystals has been improved to wafer or meter scale,where the nucleation control during the growth process is particularly important.Therefore,it is essential to conduct a comprehensive review of nucleation control to gain fundamental insights into the growth of 2D single-crystal materials.This review mainly focuses on two aspects:controlling nucleation density to enable the growth from a single nucleus,and controlling nucleation position to achieve the unidirectionally aligned islands and subsequent seamless stitching.Finally,we provide an overview and forecast of the strategic pathways for emerging 2D materials.
基金financially supported by the National Natural Science Foundation of China (62004089,62374053, 62474187 and 12235006)the Special Zone Support Program for Outstanding Talents of Henan University+4 种基金the Shenzhen Basic Research Program (JCYJ20220818101612027)the Guangdong Basic and Applied Basic Research Foundation (2024A1515012494)the Henan Province Postdoctoral Science Foundation (J23029Y)the Natural Science Foundation of Henan Province (232300420412)the Science and Technology Tackling Project of Henan Province (242102210160)
文摘Although three-dimensional metal halide perovskites are promising candidates for direct X-ray detection,the ion migration of perovskites seriously affects the detector stability.Herein,face-/edge-shared 3D heterometallic glycinate hybrid perovskitoid Pb_(2)CuGly_(2)X_(4)(Gly=-O_(2)C-CH_(2)-NH_(2);X=Cl,Br)single crystals(SCs),in which the adjacent lead halide layers are linked by large-sized Cu(Gly)_(2)pillars,are synthesized in water.The Cu(Gly)_(2)pillars in combination with face-/edge-shared inorganic skeleton are found able to synergistically suppress the ion migration,delivering a high ion migration activation energy(Ea)of 1.06 eV.The Pb_(2)CuGly_(2)Cl_(4)SC X-ray detector displays extremely low dark current drift of 1.20×10^(-9)nA mm^(-1)s^(-1)V^(-1)under high electric field(120 V mm^(-1))and continuous X-ray irradiation(2.86 Gy),and a high sensitivity of 9,250μC Gy^(-1)cm^(-2)is also achieved.More excitingly,the Pb_(2)CuGly_(2)Cl_(4)nanocrystal can be easily dispersed in water and directly blade-coated on thin-film transistor(TFT)array substrate,and the obtained Pb_(2)CuGly_(2)Cl_(4)-based TFT array detector offers an X-ray imaging capability with spatial resolution of 2.2 lp mm^(-1).
文摘We study the topological states(TSs)of all-dielectric honeycomb valley photonic crystals(VPCs).Breaking the space inversion symmetry of the honeycomb lattice by varying the filling ratio of materials for circular ring dielectric columns in the unit cell,which triggers topological phase transitions and thus achieves topological edge states(TESs)and topological corner states(TCSs).The results demonstrate that this structure has efficient photon transmission characteristics and anti-scattering robustness.In particular,we have found that changing the type of edge splicing between VPCs with different topological properties produces a change in the frequency of TCSs,and then based on this phenomenon,we have used a new method of adjusting only the type of edge splicing of the structure to design a novel TCSs combiner that can integrate four TCSs with different frequencies.This work not only expands the variety and number of unexplored TCSs that may exist in a fixed photonic band gap and can be rationalized to be selectively excited in the fixed configuration.Our study provides a feasible pathway for the design of integrated optical devices in which multiple TSs coexist in a single photonic system.
基金supported by the National Natural Science Foundation of China (No. 22101043)the Fundamental Research Funds for the Central Universities (Nos. N2205013, N232410019, N2405013)+2 种基金Natural Science Foundation of Liaoning Province (No. 2023-MSBA-068)the Opening Fund of State Key Laboratory of Heavy Oil Processing (No. SKLHOP202203006)Northeastern University。
文摘The separation of alicyclic ketones and alicyclic alcohols is one of the challenges in the field of petrochemical industry. However, traditional separation methods suffer from excessive energy consumption,complicated operation, and unsatisfactory separation efficiency for substances with similar boiling points.Herein, we offer an innovative method for the separation of alicyclic ketones and alicyclic alcohols employing nonporous adaptive crystals(NACs) of perethylated pillar[5]arene(EtP5) and perethylated pillar[6]arene(Et P6). NACs of EtP5 cannot adsorb either alicyclic ketones or alicyclic alcohols because of the small cavity size of Et P5. By contrast, NACs of Et P6 can separate cyclopentanone from the vapor mixture of cyclopentanone/cyclopentanol(v:v = 1:1) and cyclohexanone from the vapor mixture of cyclohexanone/cyclohexanol(v:v = 1:1) with purities of 99.1% and 100%, respectively. Density functional theory calculations show that the selectivity comes from the thermodynamic stability of the newly formed crystal structure after adsorption of the preferred vip molecule. Moreover, NACs of Et P6 can be reused without losing selectivity and performance.
基金supported by National Key R&D Program of China (Grant Nos.2022-YFA1403800,2023YFA1406000,and 2023YFA1406500)the National Natural Science Foundation of China (Grant Nos.12274459,12474002,22171283,and 52130103)+1 种基金China Postdoctoral Science Foundation (Grant No.2023M730011)supported by the Synergetic Extreme Condition User Facility (SECUF,https://cstr.cn/31123.02.SECUF)。
文摘Chiral topological semimetals hosting multifold fermions and exotic surface states represent a frontier in topological materials research. Among them, noncentrosymmetric cubic B20 compounds—notably transitionmetal silicides and germanides—offer a unique platform for realizing symmetry-protected topological phases and unconventional optoelectronic responses. Here, we report the physical properties of Rh Ge and Co Ge single crystals with B20 structure in detail. Transport measurements revea metallic behavior with characteristic Fermi-liquid scaling at low temperatures, while magnetization results confirm paramagnetism in both compounds. In addition,both materials exhibit low carrier concentrations with small electronic specific heat coefficients, indicating their semimetal feature with weak electronic correlations. Such high-quality Co Ge and Rh Ge single crystals provide a material platform to explore the evolution of multifold fermions and the instability of helicoid-arc surface states with spin–orbit coupling and surface environment in B20 material systems.
基金supported by the Ministry of Science and Technology of China through the National Key R&D Plan(Nos.2022YFA1205900,2022YFB3603801)Chinese Academy of Sciences(Hundred Talents Plan,Youth Innovation Promotion Association),the Strategic Priority Research Program of Sciences(No.XDB0520201)+1 种基金Young Scientists in Basic Research(No.YSBR-053)National Natural Science Foundation of China(Nos.T2225028,22475219,22075295,U22A6002,U21A20497)。
文摘Advances in controllable growth of ultra thin two-dimensional molecular crystals(2DMCs)or even monolayer molecular crystals(MMCs)propelled their application in high-performance,high-sensitivity,lowcontact-resistance optoelectronic devices.However,the rational molecular design strategies for materials prone to grow into ultrathin 2DMC or MMC have rarely been addressed.Here,systematically tailoring theπ-conjugation and alkyl chain types of asymmetric anthracene derivatives,2DMCs and even MMCs were obtained under the synergetic regulation of inter-and intralayer interactions.High-quality MMCs were obtained for SAP-C6 by traditional physical vapor transport technique(PVT),and corresponding organic field-effect transistors(OFETs)exhibited high mobility of 3.22 cm^(2)V^(-1)s^(-1).In addition,band-like charge transport with low activation energy was achieved by SAP-C6 MMC-OFETs.Furthermore,the SAPC6 MMC-based device exhibits excellent thermal stability,retaining~70%of its initial performance at 140℃in air,which is the first report on the thermal stability of MMC devices.This research highlights the potential of alkyl-substituted asymmetric molecules as a design strategy to achieve ultrathin 2DMC or MMC growth,and improve the mobility and thermal stability in OFETs.
基金supported by the Self-Deployment Project Research Program of the Haixi Institutes,Chinese Academy of Sciences(No.CXZX-2022-GH09)the National Natural Science Foundation of China(No.11774103)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR114)。
文摘Realizing the valley Hall effect by breaking the spatial inversion symmetry of photonic systems has become a cutting-edge field of micro-nano-optics,since the valley degree of freedom was introduced into photonic system.Various novel devices based on the domain walls of the valley photonic crystals have also been demonstrated.In this article,we investigate the variation of edge states by the modulation of refractive index within the domain walls,and the geometric difference between the dielectric columns of the sublattices.Straight photonic crystal waveguides with three types of domain walls(bearded,zigzag,armchair)are constructed.Simulation results show that the creation of a double-edge state in the band diagram results in two windows of stable transmission in tunable bands.Our findings might have significant implications in the field of novel optical devices.
