Tin-lead(Sn-Pb)halide perovskite single crystals combine narrow bandgaps,long carrier diffusion lengths,and low trap densities,positioning them as ideal candidates for near-infrared(NIR)optoelectronics.However,convent...Tin-lead(Sn-Pb)halide perovskite single crystals combine narrow bandgaps,long carrier diffusion lengths,and low trap densities,positioning them as ideal candidates for near-infrared(NIR)optoelectronics.However,conventional growth strategies rely on bulk crystallization at elevated temperatures,leading to uncontrolled nucleation,Sn^(2+)oxidation,and poor compatibility with planar integration.Here,we develop a coordination-engineered crystallization strategy that enables direct,lowtemperature growth of micrometer-thick Sn-Pb single-crystal thin films on device-compatible substrates.By modulating metal-solvent coordination strength using a low-donor number cosolvent system,we delineate a narrow processing window that stabilizes precursor speciation,lowers the nucleation barrier,and guides directional crystal growth under mild thermal conditions(<40℃).The resulting crystal films exhibit smooth morphology,high crystallinity,compositional uniformity,and ultralow trap densities(~3.98×10^(12)cm^(-3)).When integrated into NIR photodetectors,these films deliver high responsivity(0.51 A W^(-1)at 900 nm),specific detectivity up to 3.6×10^(12)Jones,fast response(~188μs),and>25,000 cycles of ambient operational stability.This approach establishes a scalable platform for redox-stable,low-temperature growth of Sn-Pb perovskite crystal films and expands the processing-structure-function landscape for next-generation infrared optoelectronics.展开更多
4-Bromo-3-methylphenol(BMP)is an important chemical intermediate with wide applications in the fields of medicine and pesticides.The synthesis of BMP from m-cresol via bromination is easy to carry out on an industrial...4-Bromo-3-methylphenol(BMP)is an important chemical intermediate with wide applications in the fields of medicine and pesticides.The synthesis of BMP from m-cresol via bromination is easy to carry out on an industrial scale.However,due to the formation of regioisomeric impurities during bromination and the low melting point of BMP,the separation process is prone to the formation of oily substances,resulting in low yield and purity.In this work,a new cocrystallization engineering approach was proposed to separate and purify BMP.Through design of experiments,the cocrystallization process of BMP and triethylenediamine(DABCO)was optimized using a minimum-run resolution IV screening design combined with response surface methodology.In addition,the obtained 2BMP-DABCO powder was characterized by thermal analysis,powder X-ray diffraction,infrared spectroscopy,and scanning electron microscopy.Single crystals of 2BMP-DABCO were grown from acetone by slow evaporation,and detailed structural information was obtained through single-crystal X-ray diffraction.The self-assembly mechanism was further clarified by density functional theory calculations.This study provides a simple,robust,and scalable method for the production of BMP and offers a reference for the separation and purification of phenolic substances.展开更多
Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'...Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.展开更多
An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mod...An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mode area and nonlinear coefficient were investigated by using finite element method(FEM),the evolu-tion of optical pulses propagating along the fiber was simulated,and the supercontinuum and the coherence were analyzed and evaluated under different pumping conditions.The results show that a supercontinuum spectrum with a spectral width of 4.852μm can be obtained in the proposed fiber with d_(1)/Λof 0.125,d_(2)/Λof 0.583 and the zero-dispersion wavelength of 3.228μm by pumping with a Gaussian pulse with a peak power of 800 W and a full width at half maximum(FWHM)of 20 fs at wavelength of 3.3μm.When the fiber is pumped by the pulse with the peak power of 2000 W,the FWHM of 80 fs at the wavelength of 4.0μm in the in the anomalous dispersion region,the modulation instability is obviously suppressed,and the high-coher-ence supercontinuum spectrum spanning from 1.1μm to 8.99μm is observed.A part of the pulse energy is transferred to the anomalous dispersion region when pumped at the wavelength of 2.8μm in the normal dis-persion region and a broadband high-coherence supercontinuum spectrum extending from 0.8μm to 9.8μm is generated in the 10 mm proposed fiber.This paper introduces elliptical air holes in the Al_(0.24)Ga_(0.76)As photonic crystal fiber,which enhances flexibility for tailoring the performance of supercontinuum,ultimately achieving the broadest supercontinuum spectrum with the shortest fiber length to date.展开更多
In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,cry...In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,crystallization behaviours and mechanical properties were investigated.FTIR,Raman spectroscopy and nuclear magnetic resonance spectroscopy microstructure analysis showed that the silico-oxygen network was damaged,while the increase of[AlO_(4)]content repaired the glass network,and finally made the glass network have better connectivity,with the decrease of SiO_(2).The thermal analysis confirmed the increasing glass transition and crystallization temperatures from growing Al_(2)O_(3)content.In addition,different crystal phases can be precipitated in the glass matrix,such as LiAlSi_(4)O_(10),Li_(2)Si_(2)O_(5) in glass with low Al_(2)O_(3)content,the combination of Li_xAl_xSi_(1-x)O_(2),LiAlSi_(3)O_(8),Li_(2)SiO_(3)in glass with intermediate Al_(2)O_(3)content,and the combination of LiAlSi_(2)O_(6),SiO_(2)in glass with high Al_(2)O_(3)content.The hardness of as-prepared glass gradually increases with the increase of the Al_(2)O_(3)content.The Vickers hardness of the glass-ceramics is highly dependent on the Al_(2)O_(3)content in the glass and the heat treatment temperatures,reaching a maximum of 10.11 GPa.Scanning electron microscope images show that the crystals change from spherical to massive and finally to sheet.The change of glass structure,crystal phase and morphology is the main reason for the different mechanical properties.展开更多
Achieving simultaneous enhancement of crystallinity and optimal domain size remains a fundamental challenge in organic photovoltaics(OPVs),where conventional crystallization strategies often trigger excessive aggregat...Achieving simultaneous enhancement of crystallinity and optimal domain size remains a fundamental challenge in organic photovoltaics(OPVs),where conventional crystallization strategies often trigger excessive aggregation of small-molecule acceptors.This work pioneers a kinetic paradigm for resolving the crystallinity-domain size trade-off in organic photovoltaics through dual-additive-guided stepwise crystallization.By strategically pairing 1,2-dichlorobenzene(o-DCB,low binding energy to Y6)and 1-fluoronaphthalene(FN,high binding energy),we achieve temporally decoupled crystallization control:o-DCB first mediates donor-acceptor co-crystallization during film formation,constructing a metastable network,whereupon FN induces confined Y6 crystallization within this framework during thermal annealing,refining nanostructure without over-aggregation.Morphology studies reveal that this synergy enhances crystallinity of(100)diffraction peaks by 21%–10%versus single-additive controls(o-DCB/FN alone),while maintaining optimal domain size.These morphological advantages yield balanced carrier transport(μh/μe=1.23),near-unity exciton dissociation(98.53%),and a champion power conversion efficiency(PCE)of 18.08%for PM6:Y6,significantly surpassing single-additive devices(o-DCB:17.20%;FN:17.53%).Crucially,the dual-additive strategy demonstrates universal applicability across diverse active layer systems,achieving an outstanding PCE of 19.27%in PM6:L8-BO-based devices,thereby establishing a general framework for morphology control in high-efficiency OPVs.展开更多
Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical pr...Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.展开更多
Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°...Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°(S90)to the rolling direction,were subjected to three-point bending tests.In-situ digital image correlation(DIC)system was employed to capture the strain fields.Electron backscatter diffraction(EBSD)was used to examine the through-thickness microstructures.A crystal plasticity finite element method(CPFEM)incorporating twinning and slip mechanisms was developed to simulate the bending deformation.The texture effect on the neutral layer shift and twinning behaviors was systematically investigated in terms of both experiments and simulations.The results show that CPFEM effectively simulated the texturedependent shifting behaviors of neutral layer and the associated twinning behaviors.Particularly,the spatial distributions of neutral layer across the entire bent plates were captured by both DIC and CPFEM.Additionally,some unusual twinning behaviors were analyzed in depth,such as the{10-12}-{10-12}secondary twins in S90,localized twin bands in S0,and the twin traces difference in S45.These findings reveal a close relationship between the neutral layer shift and twinning activity induced by the initial texture and strain levels.This work provides valuable insights into the bending deformation mechanisms of Mg alloys and has important implications for improving their formability and controlling springback.展开更多
High-performance lead-free piezoelectric single crystals are urgently needed for next-generation actuators and transducers.In this study,we reveal that a compositionally driven tetragonal-pseudocubic(T-PC)phase bounda...High-performance lead-free piezoelectric single crystals are urgently needed for next-generation actuators and transducers.In this study,we reveal that a compositionally driven tetragonal-pseudocubic(T-PC)phase boundary,in conjunction with an octahedral order-disorder tilting transition,significantly enhances the piezoelectric response in Nb^(5+)-substitution(Bi_(0.48)Na_(0.425)K_(0.055)Ba_(0.04))(Ti_(0.98)Nb_(0.02))O_(3)(BNKBT-2Nb)single crystals.The crystal achieves an outstanding piezoelectric coefficient of d33=662 pC/N at room temperature.In situ X-ray diffraction confirms an electric field-induced transition from the PC to T phase.Atomic-resolution HADDF-STEM analysis reveals an increase in the c/a ratio(c/a>1.01)on the local scale and ordered octahe-dral tilting of the a^(0)a^(0)c+type driven by the poling field.The single crystals exhibit excellent piezoelectric per-formance over a broad temperature range,achieving a peak d_(33) of 920 pC/N at approximately 92℃.Furthermore,the polar states exhibit a pronounced frequency dependence near the depolarization temperature.These findings provide critical insight into the structure-property relationship and offer a promising pathway for designing advanced lead-free piezoelectric crystals for functional electromechanical applications.展开更多
A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi veloci...A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi velocity,and degeneracy factor.Simulation results demonstrate that the proposed structure generates multiple photonic bandgaps within the THz frequency range.In the low-THz region,pronounced resonant transmission peaks emerge,enabling near-perfect filtering performance.The positions of these defect modes can be dynamically tuned by adjusting the Fermi level and degeneracy factor.In mid-and high-THz frequency bands,the Dirac semimetal begins to exhibit metallic behavior,leading to attenuation of the transmission peaks and the appearance of absorption.The elevation of the Fermi level delays the critical threshold for the transition from the dielectric state to the metallic state,while an increase in Fermi velocity suppresses metallic behavior.Therefore,enhancing both the Fermi level and Fermi velocity contributes to strengthening the defect peak intensity.Conversely,increasing the degeneracy factor strengthens the metallic characteristics,thereby disrupting the high-frequency photonic bandgap.Notably,the defect layer thickness and incident angle exert significant influence on the transmission behavior:a larger incident angle causes the defect peak to shift toward higher frequencies and reduces its intensity,whereas a thicker defect layer shifts the defect peak toward lower frequencies.The modulation effects of both parameters become more pronounced as frequency increases.Compared with conventional photonic crystals,our work can provide a tunable structure over transmission properties,offering novel strategies for designing tunable filters and optical sensors.展开更多
Color filters are essential components for optical modulation.However,conventional filters are restricted to operating exclusively in either reflective or transmissive mode.Furthermore,they suffer from limited UV and ...Color filters are essential components for optical modulation.However,conventional filters are restricted to operating exclusively in either reflective or transmissive mode.Furthermore,they suffer from limited UV and thermal stability,low color purity,and exhibit identical coloration on both surfaces.Herein,we propose a novel design strategy for trans-reflective color filters by integrating the absorptive properties of dye-doped polysulfone(PSU)with the diffractive capabilities of photonic crystals.This composite filter achieved broad-spectrum transmission with deep color outputs—yellow(0.410,0.510),magenta(0.446,0.231),and cyan(0.201,0.425)—closely aligned with standard color space coordinates.By tuning the refractive index of CeO_(2)@SiO_(2)nanoparticles to match dye-based PSU matrix,the transmittance of filters exceeded 70%.Moreover,dye-mediated absorption reduces the scattering light,thereby enhancing reflection color purity(full width at half maxima(FWHM)=25 nm)and producing vibrant blue,green,and red hues.The incorporation of UV-absorbing CeO_(2)@SiO_(2)nanoparticles effectively mitigated dye photodegradation,yielding exceptional UV stability(ΔT<2%under prolonged UV exposure).The filters also exhibited outstanding thermal stability(ΔT<1%after 30 min heat treatment at 230°C).This work establishes a robust materials design framework for multifunctional optical filters,advancing the development of highfidelity dual-mode color systems for next-generation display technologies.展开更多
Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On ...Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.展开更多
Sliver defects are a group of low-to-medium angle misoriented grains in Ni-based single crystal superalloys that have received more attention in recent years.Occurrence of these defects can negatively affect the mecha...Sliver defects are a group of low-to-medium angle misoriented grains in Ni-based single crystal superalloys that have received more attention in recent years.Occurrence of these defects can negatively affect the mechanical properties of single crystal components.Therefore,studying the mechanisms of sliver formation and its effects on the final properties of alloys is of great importance.In this article,recent studies on the sliver defects were reviewed.Accordingly,the mechanisms of sliver formation as well as factors contributing to sliver initiation were studied.Additionally,effects of slivers on the mechanical properties of single crystal superalloys were discussed.Dendrite deformation and dendrite fracture are the main mechanisms for the sliver formation.This is a consequence of local stress concentration on dendrites during solidification.Therefore,locations such as inclusions,pores,geometrically complex areas,mould walls,freckle channels,etc.can be considered as the potential factors that promote the sliver initiation.Sliver formation significantly degrades the creep life of single-crystal superalloys.Studies have shown that when crystallographic misorientation exceeds approximately15°,creep life can be reduced by up to 47%.Despite the absence of a standardized criterion for predicting or preventing sliver initiation and propagation,their occurrence can be minimized through optimization of solidification parameters,careful grain selection,proper casting geometry design,and rigorous control of material purity and equipment conditions.展开更多
Dimethylphenols serve as important intermediates in synthesizing pharmaceuticals and agrochemicals,yet traditional distillation struggles to separate their isomers due to minimal boiling point differences,and the deve...Dimethylphenols serve as important intermediates in synthesizing pharmaceuticals and agrochemicals,yet traditional distillation struggles to separate their isomers due to minimal boiling point differences,and the development of melt crystallization is hampered by lacking solid–liquid equilibrium (SLE) data for some isomers.Therefore,the SLE data of both binary and ternary mixtures of 2,3-dimethylphenol (2,3-DMP),3,5-dimethylphenol (3,5-DMP),and 3,4-dimethylphenol (3,4-DMP) were determined by using differential scanning calorimetry in this work.Additionally,crystallographic analysis was conducted to investigate the thermodynamic characteristics of these mixtures.The experimental results indicated that all the systems investigated in this research exhibited eutectic behavior.The experimentally obtained SLE data were well correlated with the Wilson and non-random two-liquid models.The excess thermodynamic functions were calculated to analyze the types and intensities of the molecular interactions occurring in the mixtures.Furthermore,this study developed a model for the correlation between the theoretical crystallization yield and the actual cooling yield and final yield in melt crystallization.This study has furnished reliable data essential for developing and optimizing the melt crystallization process of mixtures of 2,3-DMP,3,5-DMP,and 3,4-DMP.展开更多
The chemical structure of polyamide 6(PA6)dictates that only 50%of hydrogen bonds participate in crystallization during the crystallization process,resulting in the properties of its products being significantly depen...The chemical structure of polyamide 6(PA6)dictates that only 50%of hydrogen bonds participate in crystallization during the crystallization process,resulting in the properties of its products being significantly dependent on the molding process.Therefore,the design and development of nucleating agents suitable for PA6 holds great practical significance for high-performance PA6 materials.Amide-based nucleating agents can effectively improve the crystallization rate by increasing intermolecular hydrogen bond density.Further introduction of hydroxyl groups can enhance the hydrogen bonding interactions between the nucleating agent and PA6.In this study,a hydroxyl-containing amidebased nucleating agent,BHT,was designed and synthesized using a tyramine-based biomass as the raw material.These results demonstrated that BHT exhibited good structural compatibility with PA6.After adding 1 wt%BHT,the crystallization temperature of PA6 increased from 170.9℃to 193.3℃,the crystallinity increased 16.6%,the heat distortion temperature and Vicat softening temperature rose to 89.5 and 187.8℃,respectively,the haze decreased to 46%,achieving the synergistic optimization of mechanical,thermal,and optical properties.The in situ time-resolved FTIR results indicated that the addition of BHT increased the enthalpy of hydrogen bond formation during the nucleation stage,facilitated the segmental conformation adjustment of PA6,and enhanced the molar concentration of trans-conformations,ultimately leading to an improvement in the crystallization rate.展开更多
The crystallization and aggregation characteristics of the active layer components in organic solar cells(OSCs)are one of the core factors determining photovoltaic performance,influencing the entire process from light...The crystallization and aggregation characteristics of the active layer components in organic solar cells(OSCs)are one of the core factors determining photovoltaic performance,influencing the entire process from light absorption to charge separation,transport,and ultimately charge collection.Dynamic changes in crystallization and aggregation states can also disrupt the microstructure of the active layer,thus shortening the lifetime of the cell.In this study,a morphology modulation strategy is proposed to regulate the crystallization kinetics of non-fullerene acceptors by employing the polymer molecule PYIT as a nucleating agent.An appropriate amount of PYIT was first completely dissolved with the non-fullerene acceptor Y6 and left to stand for 24 h,followed by the fabrication of layer-by-layer processed OSCs.Experiments demonstrated that high crystallinity of PYIT allows it to act as a crystallization nucleus,promoting the crystallization,orientation consistency,and ordered stacking of the acceptor.These nanoscale structural optimizations facilitate efficient charge transport,enhance exciton dissociation efficiency,and suppress unfavorable energetic disorder.Consequently,not only was the power conversion efficiency(PCE)of D18-Cl/Y6-based layer-by-layer processed OSC increased from 18.08%to 19.13%,but the atmospheric stability and long-term lifetime of the OSCs were also significantly improved.Notably,this strategy is also applicable to indoor OSCs,and the PYIT-optimized device can achieve a PCE of 27.0%under 1000 lux light-emitting diode(LED,3200K)irradiation,which is superior to that of the control device(24.2%).This work develops a crystal engineering strategy that is able to simultaneously optimize the microscopic morphology and charge dynamics properties in OSCs,thereby achieving simultaneous improvement in efficiency and stability.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
Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that p...Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that possess both high thermopower and rapid redox kinetics.This work addresses this challenge by leveraging our recently developed copper(Ⅰ/Ⅱ)(Cu^(+)/Cu^(2+))redox couple.We significantly enhance the performance of Cu-based liquid thermocells by integrating a thermosensitive crystallization process with etched carbon cloth electrodes,achieving synergistic improvements in thermodynamic and kinetic performance.The thermosensitive crystallization process establishes a persistent Cu^(2+)concentration gradient,boosting the thermopower from 1.47 to 2.93 mV K^(-1).Moreover,the etched carbon cloth electrodes provide a larger electroactive surface area and demonstrate a higher current density.Consequently,the optimized Cu^(+)/Cu^(2+)system achieved an exceptional normalized power density P_(max)(ΔT)^(-2)of 3.97 mW m^(-2)K^(-2).A thermocell module comprised of 20 cells directly power various electronic devices at a temperature difference of 40 K.This work successfully exhibits potential of Cu^(+)/Cu^(2+)redox couple in thermoelectric conversion and introduces a valuable redox couple for highperformance thermocells.展开更多
FAPbI3 has been extensively employed in high-performance perovskite solar cells(PSCs)owing to its optimal bandgap and outstanding optoelectronic properties.Nevertheless,it readily undergoes the formation of a photo-in...FAPbI3 has been extensively employed in high-performance perovskite solar cells(PSCs)owing to its optimal bandgap and outstanding optoelectronic properties.Nevertheless,it readily undergoes the formation of a photo-inactiveδ-phase during crystallization,and achieving high-qualityα-phase films becomes even more challenging in antisolvent-free fabrication processes.This study introduces a crystallization control strategy based on 2-dimethylaminopyridine(2-DMAP)ligand engineering to establish a“fast nucleation-slow growth”dual-time-domain crystallization mechanism.2-DMAP facilitates the formation of a functional intermediate phase(2-DMAP·PbI_(2)·DMSO)that enables a direct transformation to theα-FAPbI3 phase and effectively suppresses theδ-phase pathway.Theoretical calculations and systematic experimental characterizations demonstrate that 2-DMAP exhibits stronger binding affinity and a greater charge polarization effect than dimethylsulfoxide(DMSO).This promotes the formation of high-density nuclei during spin coating and delays excessive grain growth during annealing,leading to perovskite films with improved crystallinity,fewer defects,and longer carrier lifetimes.As a result,an antisolvent-free PSC device was successfully fabricated,achieving a power conversion efficiency(PCE)of 25.10%,one of the highest reported for antisolvent-free spin-coating systems.Under ISOS-L-1 standard conditions,the device retained 84.78%of its initial efficiency after 1500 h of continuous illumination,demonstrating excellent operational stability.Moreover,it exhibited remarkable long-term stability under harsh humid and thermal conditions.This work offers a valuable strategy for the large-scale fabrication of high-performance and antisolvent-free PSCs.展开更多
Ambient-air,moisture-assisted annealing is widely used in fabricating perovskite solar cells(PSCs).However,the inherent sensitivity of perovskite intermediate-phase to moisture—due to fast and spontaneous intermolecu...Ambient-air,moisture-assisted annealing is widely used in fabricating perovskite solar cells(PSCs).However,the inherent sensitivity of perovskite intermediate-phase to moisture—due to fast and spontaneous intermolecular exchange reaction—requires strict control of ambient humidity and immediate thermal annealing treatment,raising manufacturing costs and causing fast nucleation of perovskite films.We report herein a self-buffered molecular migration strategy to slow down the intermolecular exchange reaction by introducing a n-butylammonium bromide shielding layer,which limits moisture diffusion into intermediate-phase film.This further endows the notably wide nucleation time and humidity windows for perovskite crystallization in ambient air.Consequently,the optimized 1.68 e V-bandgap n-i-p structured PSC reaches a record-high reverse-scan(RS)PCE of 22.09%.Furthermore,the versatility and applicability of as-proposed self-buffered molecular migration strategy are certified by employing various shielding materials and 1.53 eV-/1.77 eV-bandgap perovskite materials.The n-i-p structured PSCs based on 1.53 eV-and 1.77 eV-bandgap perovskite films achieve outstanding RS PCEs of 25.23%and 19.09%,respectively,both of which are beyond of the state-of-the-art ambient-air processed PSCs.展开更多
基金support received from the National Research Foundation of Korea(NRF)through the Ministry of Science,ICT(Information and Communication Technology),under grant numbers RS-2023-00302646 and RS-2025-02316700.
文摘Tin-lead(Sn-Pb)halide perovskite single crystals combine narrow bandgaps,long carrier diffusion lengths,and low trap densities,positioning them as ideal candidates for near-infrared(NIR)optoelectronics.However,conventional growth strategies rely on bulk crystallization at elevated temperatures,leading to uncontrolled nucleation,Sn^(2+)oxidation,and poor compatibility with planar integration.Here,we develop a coordination-engineered crystallization strategy that enables direct,lowtemperature growth of micrometer-thick Sn-Pb single-crystal thin films on device-compatible substrates.By modulating metal-solvent coordination strength using a low-donor number cosolvent system,we delineate a narrow processing window that stabilizes precursor speciation,lowers the nucleation barrier,and guides directional crystal growth under mild thermal conditions(<40℃).The resulting crystal films exhibit smooth morphology,high crystallinity,compositional uniformity,and ultralow trap densities(~3.98×10^(12)cm^(-3)).When integrated into NIR photodetectors,these films deliver high responsivity(0.51 A W^(-1)at 900 nm),specific detectivity up to 3.6×10^(12)Jones,fast response(~188μs),and>25,000 cycles of ambient operational stability.This approach establishes a scalable platform for redox-stable,low-temperature growth of Sn-Pb perovskite crystal films and expands the processing-structure-function landscape for next-generation infrared optoelectronics.
基金supported by the National Natural Science Foundation of China(22177011(R.Z.Qiao),21977012(R.Z.Qiao),and 21572018(C.Li))the National High-Level Hospital Clinical Research Funding(2023-NHLHCRF-YXHZ-ZRMS-02)the Joint Project of BRCBC(Biomedical Translational Engineering Research Center of BUCT-CJFH)(XK2020-06).
文摘4-Bromo-3-methylphenol(BMP)is an important chemical intermediate with wide applications in the fields of medicine and pesticides.The synthesis of BMP from m-cresol via bromination is easy to carry out on an industrial scale.However,due to the formation of regioisomeric impurities during bromination and the low melting point of BMP,the separation process is prone to the formation of oily substances,resulting in low yield and purity.In this work,a new cocrystallization engineering approach was proposed to separate and purify BMP.Through design of experiments,the cocrystallization process of BMP and triethylenediamine(DABCO)was optimized using a minimum-run resolution IV screening design combined with response surface methodology.In addition,the obtained 2BMP-DABCO powder was characterized by thermal analysis,powder X-ray diffraction,infrared spectroscopy,and scanning electron microscopy.Single crystals of 2BMP-DABCO were grown from acetone by slow evaporation,and detailed structural information was obtained through single-crystal X-ray diffraction.The self-assembly mechanism was further clarified by density functional theory calculations.This study provides a simple,robust,and scalable method for the production of BMP and offers a reference for the separation and purification of phenolic substances.
文摘Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.
文摘An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mode area and nonlinear coefficient were investigated by using finite element method(FEM),the evolu-tion of optical pulses propagating along the fiber was simulated,and the supercontinuum and the coherence were analyzed and evaluated under different pumping conditions.The results show that a supercontinuum spectrum with a spectral width of 4.852μm can be obtained in the proposed fiber with d_(1)/Λof 0.125,d_(2)/Λof 0.583 and the zero-dispersion wavelength of 3.228μm by pumping with a Gaussian pulse with a peak power of 800 W and a full width at half maximum(FWHM)of 20 fs at wavelength of 3.3μm.When the fiber is pumped by the pulse with the peak power of 2000 W,the FWHM of 80 fs at the wavelength of 4.0μm in the in the anomalous dispersion region,the modulation instability is obviously suppressed,and the high-coher-ence supercontinuum spectrum spanning from 1.1μm to 8.99μm is observed.A part of the pulse energy is transferred to the anomalous dispersion region when pumped at the wavelength of 2.8μm in the normal dis-persion region and a broadband high-coherence supercontinuum spectrum extending from 0.8μm to 9.8μm is generated in the 10 mm proposed fiber.This paper introduces elliptical air holes in the Al_(0.24)Ga_(0.76)As photonic crystal fiber,which enhances flexibility for tailoring the performance of supercontinuum,ultimately achieving the broadest supercontinuum spectrum with the shortest fiber length to date.
基金Funded by the National Key Research Program(No.2024-1129-954-112)National Natural Science Foundation of China(No.52372033)Guangxi Science and Technology Major Program(No.AA24263054)。
文摘In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,crystallization behaviours and mechanical properties were investigated.FTIR,Raman spectroscopy and nuclear magnetic resonance spectroscopy microstructure analysis showed that the silico-oxygen network was damaged,while the increase of[AlO_(4)]content repaired the glass network,and finally made the glass network have better connectivity,with the decrease of SiO_(2).The thermal analysis confirmed the increasing glass transition and crystallization temperatures from growing Al_(2)O_(3)content.In addition,different crystal phases can be precipitated in the glass matrix,such as LiAlSi_(4)O_(10),Li_(2)Si_(2)O_(5) in glass with low Al_(2)O_(3)content,the combination of Li_xAl_xSi_(1-x)O_(2),LiAlSi_(3)O_(8),Li_(2)SiO_(3)in glass with intermediate Al_(2)O_(3)content,and the combination of LiAlSi_(2)O_(6),SiO_(2)in glass with high Al_(2)O_(3)content.The hardness of as-prepared glass gradually increases with the increase of the Al_(2)O_(3)content.The Vickers hardness of the glass-ceramics is highly dependent on the Al_(2)O_(3)content in the glass and the heat treatment temperatures,reaching a maximum of 10.11 GPa.Scanning electron microscope images show that the crystals change from spherical to massive and finally to sheet.The change of glass structure,crystal phase and morphology is the main reason for the different mechanical properties.
基金supported by the Shaanxi Provincial High level Talent Introduction Project(5113220044)the Shaanxi Outstanding Youth Project(2023-JC-JQ-33)+8 种基金the Youth Science and Technology Talent Promotion Project of Jiangsu Association for Science and Technology(TJ-2022-088)the Project funded by China Postdoctoral Science Foundation(2023TQ0273,2023TQ0274,2023M742833)the NationalNatural Science Foundation of China(62304181)the Natural Science Basic Research Program of Shaanxi(2023-JC-QN-0726,2025JC-YBQN-469)the GuangdongBasic and Applied Basic Research Foundation(2022A1515110286,2024A1515012538)the Basic Research Programs of Taicang(TC2024JC04)the Suzhou Science and Technology Development Plan Innovation Leading Talent Project(ZXL2023183)the Fundamental Research Funds for the Central Universities(G2022KY05108,G2024KY0605,G2023KY0601)and the Aeronautical Science Foundation of China(2018ZD53047).
文摘Achieving simultaneous enhancement of crystallinity and optimal domain size remains a fundamental challenge in organic photovoltaics(OPVs),where conventional crystallization strategies often trigger excessive aggregation of small-molecule acceptors.This work pioneers a kinetic paradigm for resolving the crystallinity-domain size trade-off in organic photovoltaics through dual-additive-guided stepwise crystallization.By strategically pairing 1,2-dichlorobenzene(o-DCB,low binding energy to Y6)and 1-fluoronaphthalene(FN,high binding energy),we achieve temporally decoupled crystallization control:o-DCB first mediates donor-acceptor co-crystallization during film formation,constructing a metastable network,whereupon FN induces confined Y6 crystallization within this framework during thermal annealing,refining nanostructure without over-aggregation.Morphology studies reveal that this synergy enhances crystallinity of(100)diffraction peaks by 21%–10%versus single-additive controls(o-DCB/FN alone),while maintaining optimal domain size.These morphological advantages yield balanced carrier transport(μh/μe=1.23),near-unity exciton dissociation(98.53%),and a champion power conversion efficiency(PCE)of 18.08%for PM6:Y6,significantly surpassing single-additive devices(o-DCB:17.20%;FN:17.53%).Crucially,the dual-additive strategy demonstrates universal applicability across diverse active layer systems,achieving an outstanding PCE of 19.27%in PM6:L8-BO-based devices,thereby establishing a general framework for morphology control in high-efficiency OPVs.
基金Funded by Shandong Provincial Youth Innovation Team Development Plan of Colleges and Universities(No.2022KJ100)National Natural Science Foundation of China(No.52172019)。
文摘Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.
基金supported by the National Natural Science Foundation of China(No.52371004,52201144,52071040,U20A20230).
文摘Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°(S90)to the rolling direction,were subjected to three-point bending tests.In-situ digital image correlation(DIC)system was employed to capture the strain fields.Electron backscatter diffraction(EBSD)was used to examine the through-thickness microstructures.A crystal plasticity finite element method(CPFEM)incorporating twinning and slip mechanisms was developed to simulate the bending deformation.The texture effect on the neutral layer shift and twinning behaviors was systematically investigated in terms of both experiments and simulations.The results show that CPFEM effectively simulated the texturedependent shifting behaviors of neutral layer and the associated twinning behaviors.Particularly,the spatial distributions of neutral layer across the entire bent plates were captured by both DIC and CPFEM.Additionally,some unusual twinning behaviors were analyzed in depth,such as the{10-12}-{10-12}secondary twins in S90,localized twin bands in S0,and the twin traces difference in S45.These findings reveal a close relationship between the neutral layer shift and twinning activity induced by the initial texture and strain levels.This work provides valuable insights into the bending deformation mechanisms of Mg alloys and has important implications for improving their formability and controlling springback.
基金supported by the National Natural Science Foundation of China(Grant No.11704301)the Natural Science Basic Research Plan in Shaanxi Province of China(Program No.2022JM212)supported by the Ministry of Science and Higher Education of the Russian Federation(FSEG-2023-0016).
文摘High-performance lead-free piezoelectric single crystals are urgently needed for next-generation actuators and transducers.In this study,we reveal that a compositionally driven tetragonal-pseudocubic(T-PC)phase boundary,in conjunction with an octahedral order-disorder tilting transition,significantly enhances the piezoelectric response in Nb^(5+)-substitution(Bi_(0.48)Na_(0.425)K_(0.055)Ba_(0.04))(Ti_(0.98)Nb_(0.02))O_(3)(BNKBT-2Nb)single crystals.The crystal achieves an outstanding piezoelectric coefficient of d33=662 pC/N at room temperature.In situ X-ray diffraction confirms an electric field-induced transition from the PC to T phase.Atomic-resolution HADDF-STEM analysis reveals an increase in the c/a ratio(c/a>1.01)on the local scale and ordered octahe-dral tilting of the a^(0)a^(0)c+type driven by the poling field.The single crystals exhibit excellent piezoelectric per-formance over a broad temperature range,achieving a peak d_(33) of 920 pC/N at approximately 92℃.Furthermore,the polar states exhibit a pronounced frequency dependence near the depolarization temperature.These findings provide critical insight into the structure-property relationship and offer a promising pathway for designing advanced lead-free piezoelectric crystals for functional electromechanical applications.
文摘A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi velocity,and degeneracy factor.Simulation results demonstrate that the proposed structure generates multiple photonic bandgaps within the THz frequency range.In the low-THz region,pronounced resonant transmission peaks emerge,enabling near-perfect filtering performance.The positions of these defect modes can be dynamically tuned by adjusting the Fermi level and degeneracy factor.In mid-and high-THz frequency bands,the Dirac semimetal begins to exhibit metallic behavior,leading to attenuation of the transmission peaks and the appearance of absorption.The elevation of the Fermi level delays the critical threshold for the transition from the dielectric state to the metallic state,while an increase in Fermi velocity suppresses metallic behavior.Therefore,enhancing both the Fermi level and Fermi velocity contributes to strengthening the defect peak intensity.Conversely,increasing the degeneracy factor strengthens the metallic characteristics,thereby disrupting the high-frequency photonic bandgap.Notably,the defect layer thickness and incident angle exert significant influence on the transmission behavior:a larger incident angle causes the defect peak to shift toward higher frequencies and reduces its intensity,whereas a thicker defect layer shifts the defect peak toward lower frequencies.The modulation effects of both parameters become more pronounced as frequency increases.Compared with conventional photonic crystals,our work can provide a tunable structure over transmission properties,offering novel strategies for designing tunable filters and optical sensors.
基金supported by the Program of the National Natural Science Foundation of China(22238002)the Fundamental Research Funds for the Central Universities(DUT22-LAB610)Research and Innovation Team Project of Dalian University of Technology(DUT2022TB10).
文摘Color filters are essential components for optical modulation.However,conventional filters are restricted to operating exclusively in either reflective or transmissive mode.Furthermore,they suffer from limited UV and thermal stability,low color purity,and exhibit identical coloration on both surfaces.Herein,we propose a novel design strategy for trans-reflective color filters by integrating the absorptive properties of dye-doped polysulfone(PSU)with the diffractive capabilities of photonic crystals.This composite filter achieved broad-spectrum transmission with deep color outputs—yellow(0.410,0.510),magenta(0.446,0.231),and cyan(0.201,0.425)—closely aligned with standard color space coordinates.By tuning the refractive index of CeO_(2)@SiO_(2)nanoparticles to match dye-based PSU matrix,the transmittance of filters exceeded 70%.Moreover,dye-mediated absorption reduces the scattering light,thereby enhancing reflection color purity(full width at half maxima(FWHM)=25 nm)and producing vibrant blue,green,and red hues.The incorporation of UV-absorbing CeO_(2)@SiO_(2)nanoparticles effectively mitigated dye photodegradation,yielding exceptional UV stability(ΔT<2%under prolonged UV exposure).The filters also exhibited outstanding thermal stability(ΔT<1%after 30 min heat treatment at 230°C).This work establishes a robust materials design framework for multifunctional optical filters,advancing the development of highfidelity dual-mode color systems for next-generation display technologies.
文摘Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.
文摘Sliver defects are a group of low-to-medium angle misoriented grains in Ni-based single crystal superalloys that have received more attention in recent years.Occurrence of these defects can negatively affect the mechanical properties of single crystal components.Therefore,studying the mechanisms of sliver formation and its effects on the final properties of alloys is of great importance.In this article,recent studies on the sliver defects were reviewed.Accordingly,the mechanisms of sliver formation as well as factors contributing to sliver initiation were studied.Additionally,effects of slivers on the mechanical properties of single crystal superalloys were discussed.Dendrite deformation and dendrite fracture are the main mechanisms for the sliver formation.This is a consequence of local stress concentration on dendrites during solidification.Therefore,locations such as inclusions,pores,geometrically complex areas,mould walls,freckle channels,etc.can be considered as the potential factors that promote the sliver initiation.Sliver formation significantly degrades the creep life of single-crystal superalloys.Studies have shown that when crystallographic misorientation exceeds approximately15°,creep life can be reduced by up to 47%.Despite the absence of a standardized criterion for predicting or preventing sliver initiation and propagation,their occurrence can be minimized through optimization of solidification parameters,careful grain selection,proper casting geometry design,and rigorous control of material purity and equipment conditions.
基金funded by the National Natural Science Foundation of China(22308358,22208346,22421003)IPE Project for Frontier Basic Research(QYJC-2023-05)CAS Project for Young Scientists in Basic Research(YSBR-038).
文摘Dimethylphenols serve as important intermediates in synthesizing pharmaceuticals and agrochemicals,yet traditional distillation struggles to separate their isomers due to minimal boiling point differences,and the development of melt crystallization is hampered by lacking solid–liquid equilibrium (SLE) data for some isomers.Therefore,the SLE data of both binary and ternary mixtures of 2,3-dimethylphenol (2,3-DMP),3,5-dimethylphenol (3,5-DMP),and 3,4-dimethylphenol (3,4-DMP) were determined by using differential scanning calorimetry in this work.Additionally,crystallographic analysis was conducted to investigate the thermodynamic characteristics of these mixtures.The experimental results indicated that all the systems investigated in this research exhibited eutectic behavior.The experimentally obtained SLE data were well correlated with the Wilson and non-random two-liquid models.The excess thermodynamic functions were calculated to analyze the types and intensities of the molecular interactions occurring in the mixtures.Furthermore,this study developed a model for the correlation between the theoretical crystallization yield and the actual cooling yield and final yield in melt crystallization.This study has furnished reliable data essential for developing and optimizing the melt crystallization process of mixtures of 2,3-DMP,3,5-DMP,and 3,4-DMP.
文摘The chemical structure of polyamide 6(PA6)dictates that only 50%of hydrogen bonds participate in crystallization during the crystallization process,resulting in the properties of its products being significantly dependent on the molding process.Therefore,the design and development of nucleating agents suitable for PA6 holds great practical significance for high-performance PA6 materials.Amide-based nucleating agents can effectively improve the crystallization rate by increasing intermolecular hydrogen bond density.Further introduction of hydroxyl groups can enhance the hydrogen bonding interactions between the nucleating agent and PA6.In this study,a hydroxyl-containing amidebased nucleating agent,BHT,was designed and synthesized using a tyramine-based biomass as the raw material.These results demonstrated that BHT exhibited good structural compatibility with PA6.After adding 1 wt%BHT,the crystallization temperature of PA6 increased from 170.9℃to 193.3℃,the crystallinity increased 16.6%,the heat distortion temperature and Vicat softening temperature rose to 89.5 and 187.8℃,respectively,the haze decreased to 46%,achieving the synergistic optimization of mechanical,thermal,and optical properties.The in situ time-resolved FTIR results indicated that the addition of BHT increased the enthalpy of hydrogen bond formation during the nucleation stage,facilitated the segmental conformation adjustment of PA6,and enhanced the molar concentration of trans-conformations,ultimately leading to an improvement in the crystallization rate.
基金supported by the National Natural Science Foundation of China (NSFC grant no. 62474028, 52130304, and62222503)the Natural Science Foundation of Sichuan Province(2025ZNSFSC0037, 2025ZNSFSC1460, and 2024NSFSC1447)+1 种基金the National Key R and D Program of China (2023YFB2604101)sponsored by the Sichuan Province Key Laboratory of Display Science and Technology
文摘The crystallization and aggregation characteristics of the active layer components in organic solar cells(OSCs)are one of the core factors determining photovoltaic performance,influencing the entire process from light absorption to charge separation,transport,and ultimately charge collection.Dynamic changes in crystallization and aggregation states can also disrupt the microstructure of the active layer,thus shortening the lifetime of the cell.In this study,a morphology modulation strategy is proposed to regulate the crystallization kinetics of non-fullerene acceptors by employing the polymer molecule PYIT as a nucleating agent.An appropriate amount of PYIT was first completely dissolved with the non-fullerene acceptor Y6 and left to stand for 24 h,followed by the fabrication of layer-by-layer processed OSCs.Experiments demonstrated that high crystallinity of PYIT allows it to act as a crystallization nucleus,promoting the crystallization,orientation consistency,and ordered stacking of the acceptor.These nanoscale structural optimizations facilitate efficient charge transport,enhance exciton dissociation efficiency,and suppress unfavorable energetic disorder.Consequently,not only was the power conversion efficiency(PCE)of D18-Cl/Y6-based layer-by-layer processed OSC increased from 18.08%to 19.13%,but the atmospheric stability and long-term lifetime of the OSCs were also significantly improved.Notably,this strategy is also applicable to indoor OSCs,and the PYIT-optimized device can achieve a PCE of 27.0%under 1000 lux light-emitting diode(LED,3200K)irradiation,which is superior to that of the control device(24.2%).This work develops a crystal engineering strategy that is able to simultaneously optimize the microscopic morphology and charge dynamics properties in OSCs,thereby achieving simultaneous improvement in efficiency and stability.
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.
基金financially supported by research grants from Innovative Research Group Project of National Natural Science Foundation of China(52021004)the National Key Research and Development Program of China(2022YFB3803300)+1 种基金the National Natural Science Foundation of China(62474026,62205140,12204071)the China Postdoctoral Science Foundation(2022M710532)。
文摘Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that possess both high thermopower and rapid redox kinetics.This work addresses this challenge by leveraging our recently developed copper(Ⅰ/Ⅱ)(Cu^(+)/Cu^(2+))redox couple.We significantly enhance the performance of Cu-based liquid thermocells by integrating a thermosensitive crystallization process with etched carbon cloth electrodes,achieving synergistic improvements in thermodynamic and kinetic performance.The thermosensitive crystallization process establishes a persistent Cu^(2+)concentration gradient,boosting the thermopower from 1.47 to 2.93 mV K^(-1).Moreover,the etched carbon cloth electrodes provide a larger electroactive surface area and demonstrate a higher current density.Consequently,the optimized Cu^(+)/Cu^(2+)system achieved an exceptional normalized power density P_(max)(ΔT)^(-2)of 3.97 mW m^(-2)K^(-2).A thermocell module comprised of 20 cells directly power various electronic devices at a temperature difference of 40 K.This work successfully exhibits potential of Cu^(+)/Cu^(2+)redox couple in thermoelectric conversion and introduces a valuable redox couple for highperformance thermocells.
基金supported by the National Natural Science Foundation of China (62374104, 62374103)the Taishan Scholar Foundation of Shandong Province (tsqn2023120051105)+1 种基金the Natural Science Foundation of Shandong Province (ZR2023QE321)the Shandong University-Muerhls Joint Laboratory
文摘FAPbI3 has been extensively employed in high-performance perovskite solar cells(PSCs)owing to its optimal bandgap and outstanding optoelectronic properties.Nevertheless,it readily undergoes the formation of a photo-inactiveδ-phase during crystallization,and achieving high-qualityα-phase films becomes even more challenging in antisolvent-free fabrication processes.This study introduces a crystallization control strategy based on 2-dimethylaminopyridine(2-DMAP)ligand engineering to establish a“fast nucleation-slow growth”dual-time-domain crystallization mechanism.2-DMAP facilitates the formation of a functional intermediate phase(2-DMAP·PbI_(2)·DMSO)that enables a direct transformation to theα-FAPbI3 phase and effectively suppresses theδ-phase pathway.Theoretical calculations and systematic experimental characterizations demonstrate that 2-DMAP exhibits stronger binding affinity and a greater charge polarization effect than dimethylsulfoxide(DMSO).This promotes the formation of high-density nuclei during spin coating and delays excessive grain growth during annealing,leading to perovskite films with improved crystallinity,fewer defects,and longer carrier lifetimes.As a result,an antisolvent-free PSC device was successfully fabricated,achieving a power conversion efficiency(PCE)of 25.10%,one of the highest reported for antisolvent-free spin-coating systems.Under ISOS-L-1 standard conditions,the device retained 84.78%of its initial efficiency after 1500 h of continuous illumination,demonstrating excellent operational stability.Moreover,it exhibited remarkable long-term stability under harsh humid and thermal conditions.This work offers a valuable strategy for the large-scale fabrication of high-performance and antisolvent-free PSCs.
基金the financial support from the National Key R&D Program of China(2021YFF0500500)the National Natural Science Foundation of China(62474131,62274132,and 62204189)。
文摘Ambient-air,moisture-assisted annealing is widely used in fabricating perovskite solar cells(PSCs).However,the inherent sensitivity of perovskite intermediate-phase to moisture—due to fast and spontaneous intermolecular exchange reaction—requires strict control of ambient humidity and immediate thermal annealing treatment,raising manufacturing costs and causing fast nucleation of perovskite films.We report herein a self-buffered molecular migration strategy to slow down the intermolecular exchange reaction by introducing a n-butylammonium bromide shielding layer,which limits moisture diffusion into intermediate-phase film.This further endows the notably wide nucleation time and humidity windows for perovskite crystallization in ambient air.Consequently,the optimized 1.68 e V-bandgap n-i-p structured PSC reaches a record-high reverse-scan(RS)PCE of 22.09%.Furthermore,the versatility and applicability of as-proposed self-buffered molecular migration strategy are certified by employing various shielding materials and 1.53 eV-/1.77 eV-bandgap perovskite materials.The n-i-p structured PSCs based on 1.53 eV-and 1.77 eV-bandgap perovskite films achieve outstanding RS PCEs of 25.23%and 19.09%,respectively,both of which are beyond of the state-of-the-art ambient-air processed PSCs.
