Primordial black holes(PBHs) offer a compelling candidate for dark matter. The production of PBHs through well-tested and accepted physical processes is highly worthy of investigation. This work highlights the role of...Primordial black holes(PBHs) offer a compelling candidate for dark matter. The production of PBHs through well-tested and accepted physical processes is highly worthy of investigation. This work highlights the role of turbulences in the very early universe in sustaining intense and persistent fluctuations in energy or mass density,which could provide a natural mechanism for PBH formation in the primordial universe. We analyze the mass range and abundance of PBHs produced in the magnetohydrodynamic turbulence induced by the electroweak phase transition. Remarkably, we find that the mass range of the produced PBHs falls within the most viable“asteroid mass” window from the present-day observations, and within natural parameter regions their abundance can be sufficiently large. These findings suggest that PBHs produced during magnetohydrodynamic turbulence in the very early universe may comprise a dominant part of dark matter.展开更多
We assume exponential corrections to the entropy of 5D charged Ad S black hole solutions,which are derived within the framework of Einstein-Gauss-Bonnet gravity and nonlinear electrodynamics.Additionally,we consider t...We assume exponential corrections to the entropy of 5D charged Ad S black hole solutions,which are derived within the framework of Einstein-Gauss-Bonnet gravity and nonlinear electrodynamics.Additionally,we consider two distinct versions of 5D charged Ad S black holes by setting the parameters q→0 and k→0(where q represents the charge,and k is the non-linear parameter).We investigate these black holes in the extended phase space,where the cosmological constant is interpreted as pressure,demonstrating the first law of black hole thermodynamics.The focus extends to understanding the thermal stability or instability,as well as identifying first and second-order phase transitions.This exploration is carried out through the analysis of various thermodynamic quantities,including heat capacity at constant pressure,Gibbs free energy(GFE),Helmholtz free energy(HFE),and the trace of the Hessian matrix.In order to visualize phase transitions,identify critical points,analyze stability and provide comprehensive analysis,we have made the contour plot of the mentioned thermodynamic quantities and observed that our results are very consistent.These investigations are conducted within the context of exponentially corrected entropies,providing valuable insights into the intricate thermodynamic behavior of these 5D charged Ad S black holes under different parameter limits.展开更多
The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the an...The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the analysis of characteristic lines and crossover behaviors within the supercritical region.By making use of the free energy,we introduce three key thermodynamic quantities:scaled variance,skewness,and kurtosis.Our results demonstrate that the Widom line,associated with the maximal scaled variance,can effectively differentiate between small and large black hole-like subphases,each displaying distinct thermodynamic behaviors within the supercritical region.Furthermore,by utilizing quasinormal modes,we identify the Frenkel line,offering a dynamic perspective to distinguish between small and large black hole-like subphases.These contribute to a deeper comprehension of black hole subphases in the supercritical region,thus illuminating new facets of black hole thermodynamics.展开更多
The gravitational memory effect manifests gravitational nonlinearity,degenerate vacua,and asymptotic symmetries;its detection is considered challenging.We propose using a space-borne interferometer to detect memory si...The gravitational memory effect manifests gravitational nonlinearity,degenerate vacua,and asymptotic symmetries;its detection is considered challenging.We propose using a space-borne interferometer to detect memory signals from stellar-mass binary black holes(BBHs),typically targeted by ground-based detectors.We use DECIGO detector as an example.Over 5 years,DECIGO is estimated to detect approximately 2,036 memory signals(SNRs>3)from stellar-mass BBHs.Simulations used frequency-domain memory waveforms for direct SNR estimation.Predictions utilized a GWTC-3 constrained BBH population model(Power law+Peak mass,DEFAULT spin,Madau-Dickinson merger rate).The analysis used conservative lower merger rate limits and considered orbital eccentricity.The high detection rate stems from strong memory signals within DECIGO’s bandwidth and the abundance of stellar-mass BBHs.This substantial and conservative detection count enables statistical use of the memory effect for fundamental physics and astrophysics.DECIGO exemplifies that space interferometers may better detect memory signals from smaller mass binaries than their typical targets.Detectors in lower frequency bands are expected to find strong memory signals from∼10^(4)M⊙binaries.展开更多
The photon region surrounding a black hole is crucial for distant observers to receive the emitted spectrum from its vicinity.This paper investigates the optical features of a regular spinning antide Sitter(AdS)black ...The photon region surrounding a black hole is crucial for distant observers to receive the emitted spectrum from its vicinity.This paper investigates the optical features of a regular spinning antide Sitter(AdS)black hole.These kinds of black holes hold deviation parameter k,and the cosmological constant A including their mass M and spin a.The cosmological parameter depends on the curvature radius by A=-3/l~2.We investigate the structure of geodesics for unstable circular orbits of photons as observed by an observer at specific Boyer-Lindquist coordinates(r_(O),v_(O))in the region between the outer and cosmological horizon,so-called the domain of outer communication.Our investigations include the analysis of three observables from its shadow plot:the black hole shadow radius(R_(s)),the distortion of the black hole(δ_(s)),and shadow area A.With the help of these observables,we calculate the angular diameter of the apparent size of the shadow.The shadows cast by spinning regular spacetimes are smaller compared to those produced by rotating black holes in both general relativity and regular spacetimes.We also calculate the rate at which energy is emitted from the black hole.展开更多
Elemental doping of BiVO_(4) crystal lattices effectively enhances carrier separation,thereby facilitating efficient photoelectrochemical water splitting.However,the positive effect of elementally induced lattice dist...Elemental doping of BiVO_(4) crystal lattices effectively enhances carrier separation,thereby facilitating efficient photoelectrochemical water splitting.However,the positive effect of elementally induced lattice distortions on hole extraction has been neglected.Herein,the crystal lattice of BiVO_(4) is distorted by doping with an inexpensive Cs metal;then,CoFe_(2)O_(4) is used as an efficient hole-extraction layer to further modify the surface of the doped photoanode.Benefiting from the above design,the newly prepared CoFe_(2)O_(4)-Cs-BiVO_(4) photoanode achieved a photocurrent density of 5.66 mA cm^(–2) at 1.23 V vs.a reversible hydrogen electrode,indicating a 3.9-fold improvement in photocurrent density.Detailed physicochemical characterization and density functional theory calculations showed that the lattice distortion induced by Cs doping promoted the directional migration of BiVO_(4) bulk-phase holes to the CoFe_(2)O_(4) layer.Additionally,the coupled CoFe_(2)O_(4) can be used as a hole extraction layer to further enhance the interfacial migration of carriers.The synergistic effect of the two effectively promotes the directional migration of photogenerated carriers from the BiVO_(4) bulk phase to the active sites of the oxygen evolution reaction,thereby effectively inhibiting carrier recombination.This study revealed the positive effect of the dual-hole extraction strategy on solar energy conversion,thereby opening new avenues for the rational design of photoanodes.展开更多
In this work,the influences of surface layer slurry at different temperatures(10℃,14℃,18℃,22℃)on wax patterns deformation,shrinkage,slurry coating characteristics,and the surface quality of the casting were invest...In this work,the influences of surface layer slurry at different temperatures(10℃,14℃,18℃,22℃)on wax patterns deformation,shrinkage,slurry coating characteristics,and the surface quality of the casting were investigated by using a single factor variable method.The surface morphologies of the shell molds produced by different temperatures of the surface(first)layer slurries were observed via electron microscopy.Furthermore,the microscopic composition of these shell molds was obtained by EDS,and the osmotic effect of the slurry on the wax patterns at different temperatures was also assessed by the PZ-200 Contact Angle detector.The forming reasons for the surface cracks and holes of thick and large ZTC4 titanium alloy by investment casting were analyzed.The experimental results show that the surface of the shell molds prepared by the surface layer slurry with a low temperature exhibits noticeable damage,which is mainly due to the poor coating performance and the serious expansion and contraction of wax pattern at low temperatures.The second layer shell material(SiO_(2),Al_(2)O_(3))immerses into the crack area of the surface layer,contacts and reacts with the molten titanium to form surface cracks and holes in the castings.With the increase of the temperature of surface layer slurry,the damage to the shell surface tends to weaken,and the composition of the shell molds'surface becomes more uniform with less impurities.The results show that the surface layer slurry at 22℃is evenly coated on the surface of the wax patterns with appropriate thickness,and there is no surface shell mold rupture caused by sliding slurry after sand leaching.The surface layer slurry temperature is consistent with the wax pattern temperature and the workshop temperature,so there is no damage of the surface layer shell caused by expansion and contraction.Therefore,the shell mold prepared by the surface layer slurry at this temperature has good integrity,isolating the contact between the low inert shell material and the titanium liquid effectively,and the ZTC4 titanium alloy cylinder casting prepared by this shell mold is smooth,without cracks and holes.展开更多
Strong surface impact will produce strong vibration,which will pose a threat to the safety of nearby buried pipelines and other important lifeline projects.Based on the verified numerical method,a comprehensive numeri...Strong surface impact will produce strong vibration,which will pose a threat to the safety of nearby buried pipelines and other important lifeline projects.Based on the verified numerical method,a comprehensive numerical parameter analysis is conducted on the key influencing factors of the vibration isolation hole(VIH),which include hole diameter,hole net spacing,hole depth,hole number,hole arrangement,and soil parameters.The results indicate that a smaller ratio of net spacing to hole diameter,the deeper the hole,the multi-row hole,the hole adoption of staggered arrangements,and better site soil conditions can enhance the efficiency of the VIH barrier.The average maximum vibration reduction efficiency within the vibration isolation area can reach 42.2%.The vibration safety of adjacent oil pipelines during a dynamic compaction projection was evaluated according to existing standards,and the measurement of the VIH was recommended to reduce excessive vibration.The single-row vibration isolation scheme and three-row staggered arrangement with the same hole parameters are suggested according to different cases.The research findings can serve as a reference for the vibration safety analysis,assessment,and control of adjacent underground facilities under the influence of strong surface impact loads.展开更多
Enhancing the activity of photocatalysts is a critical challenge for improving the photocatalytic degradation of contaminated wastewater.Here,a novel Ce single-atom-doped titanate nanotube photocatalyst(CeH_(2)Ti_(2)O...Enhancing the activity of photocatalysts is a critical challenge for improving the photocatalytic degradation of contaminated wastewater.Here,a novel Ce single-atom-doped titanate nanotube photocatalyst(CeH_(2)Ti_(2)O_(5)·H_(2)O)was successfully synthesized using a onepot solvothermal method.Degradation experiments revealed that the optimal Ce doping ratio was 1.0%.The ultraviolet-visible diffuse reflectance spectroscopy results showed that the bandgap of the Ce-doped sample decreased from 3.02 to 2.87 eV,enhancing the absorption in the visible spectral range.At the same time,the BrunauerEmmett-Teller specific surface area increased from 63.68 to 88.95 m^(2)g^(-1).The 1.0%Ce-H_(2)Ti_(2)O_(5)·H_(2)O(HTC_(1))could degrade 99.04%of 100 mg L-1rhodamine B(RhB)after 40 min of visible-light irradiation.The degradation efficiency decreased by only 21.24%after five cycles.The results of free-radical quenching and electron spin resonance spectroscopy analyses indicated that HTC_(1)achieved efficient degradation of RhB through a direct hole oxidation mechanism.Compared with pure protonated titanate nanotubes(H_(2)Ti_(2)O_(5)·H_(2)O),HTC_(1)had a higher specific surface area,more electron traps,narrower bandgap,longer hole lifetime,and suppressed photogenerated charge recombination rate owing to the Ce single-atom doping.展开更多
Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb...Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb,respectively.The effects of microstructure,texture,crack propagation behavior and second phase precipitation behavior on hole expansion ratio were investigated.The precipitation behavior of TiC and(Ti,Nb)C in austenite and ferrite in three groups of steel samples was calculated theoretically.The results showed that the hole expansion ratios of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 51.73%,51.17%and 66.24%following simulated coiling at 600℃,respectively.The microstructure was mainly polygonal ferrite with a small amount of pearlite.The grain refinement of 0.097Ti–0.059Nb test steel and the low texture ratio of{110}//ND improved the hole expansion ratio.The low overall hole expansion ratio was due to the microstructure inhomogeneity.The microstructure uniformity was improved by the quenching and tempering treatment,and the hole expansion ratio of the three test steels was greatly increased.The fastest precipitation temperatures in the austenitic region of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 880,860 and 830℃,while those in the ferrite region were 680,675 and 675℃,respectively.The addition of Nb element increased the volume free energy,so that the critical core size of the nucleation on the dislocation line increased,resulting in the decrease in the fastest precipitation temperature.展开更多
Heterocyclic compounds play an important role in organic hole transport materials(HTMs)for perovskite solar cells(PSCs).Herein,a series of linear D-π-D HTMs(O-CBz,S-CBz,SO_(2)-CBz)with different dibenzoheterocycles c...Heterocyclic compounds play an important role in organic hole transport materials(HTMs)for perovskite solar cells(PSCs).Herein,a series of linear D-π-D HTMs(O-CBz,S-CBz,SO_(2)-CBz)with different dibenzoheterocycles core(dibenzofuran,dibenzothiophene,dibenzothiophene sulfone)were designed and synthesized,and their applications in PSCs were investigated.The intrinsic properties(CV,UV-vis,hole mobility and conductivity)were systematically investigated,demonstrating that all three materials are suitable HTMs for planar n-i-p type PSCs.Benefiting from the excellent hole mobility and conductivity,good film forming ability,and outstanding charge extraction and transport capability of S-CBz,FAPbI_(3)-based PSCs using S-CBz as HTM achieved a PCE of 25.0%,which is superior to that of Spiro-OMeTAD-based PSCs fabricated under the same conditions(23.9%).Furthermore,due to the interaction between S and Pb^(2+),SCBz-based PSC devices exhibited improved stability.This work demonstrates that dibenzothiophene-based architectures are promising candidates for high-performance HTMs in perovskite solar cell architectures.展开更多
The level set method(LSM)is renowned for producing smooth boundaries and clear geometric representations,facilitating integration with CAD environments.However,its inability to autonomously generate new holes during o...The level set method(LSM)is renowned for producing smooth boundaries and clear geometric representations,facilitating integration with CAD environments.However,its inability to autonomously generate new holes during optimization makes the results highly dependent on the initial design.Although topological derivatives are often introduced to enable hole nucleation,their conversion into effective shape derivatives remains challenging,limiting topological evolution.To address this,a level set topology optimization method with autonomous hole formation(LSM-AHF)is proposed,integrating the material removal mechanism of the SIMP(Solid Isotropic Material with Penalization)method into the LSM framework.First,an initial structure is generated by adjusting the judgment threshold,and a binary thresholding algorithm is subsequently employed to obtain a clear and well-defined geometry.The structural boundaries of this geometry are then identified and used to construct a signed distance field,which serves as the initial level set function.To ensure smooth transitions across material interfaces and enhance numerical stability,Gaussian filtering is subsequently applied to the distance field.Numerical results demonstrate that LSMAHF effectively enables hole nucleation without manual initialization and improves topology change,addressing the respective limitations of conventional LSM and SIMP methods.展开更多
A film hole arrangement guideline along the temperature difference is proposed.The performance of different film holes arrangement and the impact of parameters are investigated though cascade wind tunnel test and nume...A film hole arrangement guideline along the temperature difference is proposed.The performance of different film holes arrangement and the impact of parameters are investigated though cascade wind tunnel test and numerical simulations.Finally,the optimized flow field structure and the mechanism of its effects are explored.Under the same operating conditions,Hole pattern#2(arrangement along the 50 K temperature difference line)can reduce coolant consumption by half while achieves the same cooling effect as original film hole arrangement.Additionally,Hole pattern#2 reduces the temperature difference between the suction and pressure sides of the vane,effectively protecting the structural strength.At mass flow ratio is 6.23%,Hole pattern#2 achieves both good cooling effectiveness and relatively saves coolant consumption,offering the highest costeffectiveness.The modulation in the position of film holes results in different local pressures affecting the flow inside the cooling chamber.The coupling of internal and external flows leads to different vortex structures near the outlet of the film holes,thereby influencing the film effectiveness.Hole pattern#2 does not exhibit significant high-cooling regions,but it shows a more uniform distribution of overall cooling effectiveness.Therefore,optimizing the arrangement of film holes and spacing them along the temperature difference is considered a crucial technical means to enhance the efficiency of gas turbines.展开更多
In this paper,a type of reinforcing structure for composite shell with single and through hole is presented.The experimental tests for the composite shells without hole,with single hole and reinforced structure,with t...In this paper,a type of reinforcing structure for composite shell with single and through hole is presented.The experimental tests for the composite shells without hole,with single hole and reinforced structure,with through hole and reinforced structure subjected to hydrostatic pressure were carried out by the designed experimental test system.The mechanical responses of the composite shells under hydrostatic pressure are obtained by the high-speed camera and strain measurement.The results show that the entire deformation process of the shell can be divided into three:uniform compression,"buckling mode formation"and buckling.The"buckling mode formation"process is captured and reported for the first time.For the composite shell with single hole,the proposed reinforcing structure has a significant reinforcement effect on the shell and the buckling capacity of the shell is not weaker than the complete composite shell.For the composite shell with through hole,sealing effect can be achieved by the proposed reinforcing structure,but the buckling capacity of the shell after reinforcement can only reach 77%of the original buckling capacity.展开更多
This study introduces a novel approach for coupled aeroelastic analysis of panel subjected to supersonic airflow,utilizing Add-On Acoustic Black Hole(AABH)to mitigate panel flutter.Employing Galerkin's method to d...This study introduces a novel approach for coupled aeroelastic analysis of panel subjected to supersonic airflow,utilizing Add-On Acoustic Black Hole(AABH)to mitigate panel flutter.Employing Galerkin's method to discretize aeroelastic equation of panel and leveraging finite element method to derive a reduced discrete model of AABH,this study effectively couples two substructures via interface displacement.Investigation into the interactive force highlights the modal effective mass,frequency discrepancy between oscillation and AABH mode,and modal damping ratio as critical factors influencing individual AABH mode in flutter suppression.The selection of effective AABH modes,closely linked to these factors,directly influences the accuracy of simulations.The results reveal that AABH notably enhances the panel's critical flutter boundary by14.6%,a significant improvement over the 3.6%increase afforded by equivalent mass.Furthermore,AABH outperforms both the tuned mass damper and nonlinear energy sink in flutter suppression efficacy.By adjusting the AABH's geometrical parameters to increase the accumulative modal effective mass within the pertinent frequency range,or choosing a suitable installation position for AABH,its performance in flutter suppression is further optimized.These findings not only underscore the AABH's potential in enhancing aeroelastic stability but also provide a foundation for its optimal design.展开更多
In the aerospace field,hole burnishing enhancement plays an essential role in improving the service performance of load-bearing holes.To satisfy the assembly accuracy and strength requirements,the structure shape and ...In the aerospace field,hole burnishing enhancement plays an essential role in improving the service performance of load-bearing holes.To satisfy the assembly accuracy and strength requirements,the structure shape and surface integrity must be considered simultaneously during the enhancement process.The current manufacturing process of hole burnishing has a relatively weak balance between the structure shape and surface integrity;therefore,it is necessary to analyze the mechanism and optimize the parameters to improve the strengthening effect of the holes.In this study,a two-dimensional longitudinal simplified model for the hole burnishing process was established,and the reasons for the surface roughness improvement of the hole wall and material accumulation on the upper surface were analyzed.Experiments were conducted to determine the influence of the burnishing parameters on the structure shape(material accumulation,shape contour,and roundness)and surface integrity(surface roughness,residual stress,and surface hardness),based on the opposite requirements of improving the structure shape and surface integrity for the burnishing depth(BD).The results showed that with an increase in the BD,the structure shape deteriorated,whereas the surface integrity improved.Fatigue behavior verification experiments were conducted,and parameter selection schemes for the collaborative improvement of the structure shape and surface integrity were discussed.For the holes of titanium alloy TB6(Ti-10V-2Fe-3Al),the fatigue life can be increased by 162%when the BD,spindle speed,and feed rate were 0.20 mm,200 r/min,and 0.2 mm/r,respectively.展开更多
AIM:To evaluate whether fluid-air exchange is an effective treatment for unclosed macular hole(MH)after primary vitrectomy.METHODS:This retrospective study included patients with an unclosed MH within 1–2wk after vit...AIM:To evaluate whether fluid-air exchange is an effective treatment for unclosed macular hole(MH)after primary vitrectomy.METHODS:This retrospective study included patients with an unclosed MH within 1–2wk after vitrectomy.Patients were divided into the vitrectomy,fluid-air exchange,and observation groups according to the secondary treatment.The anatomical outcomes and postoperative visual acuity were recorded.RESULTS:The analysis included 25 eyes in 25 patients(16 females)aged 37–74y(vitrectomy group,n=10;fluid-air exchange group,n=9;observation group,n=6).Closure rate after secondary treatment was 100%in the vitrectomy group,88.9%in the fluid-air exchange group and 33.3%in the observation group.Optical coherence tomography images obtained at the last follow-up revealed that continuity of the external limiting membrane(ELM)was significantly more common(P=0.004)in the fluid-air group(8/9 eyes,88.9%)than in the vitrectomy group(2/10 eyes,20.0%)and that macular morphology was better in the fluid-air group than in the vitrectomy group.No serious complications were observed after secondary treatment.CONCLUSION:Fluid-air exchange is an alternative option to repeat vitrectomy for patients with an unclosed MH after initial vitrectomy with elevated macular edge.展开更多
This study explores the dynamics of charged Hayward black holes,focusing on the effects of electric charge and the length factor on accretion disk characteristics.Our results show that increasing both parameters reduc...This study explores the dynamics of charged Hayward black holes,focusing on the effects of electric charge and the length factor on accretion disk characteristics.Our results show that increasing both parameters reduces the size of the event horizon and innermost stable circular orbits(ISCO)radius,with the electric charge exerting a more pronounced influence.Additionally,the length factor and electric charge can effectively replicate the spin of a Kerr black hole.Both parameters also affect the electromagnetic radiation emitted from the accretion disk,increasing the flux,temperature,and radiative efficiency.The peak radiation occurs in the soft x-ray band,with higher values of electric charge and length factor enhancing disk luminosity and shifting the peak to higher frequencies.These findings can offer valuable insights into the accretion processes around black holes and their observable signatures,particularly in x-ray astronomy.展开更多
The gravitational deflection of light signals restricted in the polar-axis plane of a moving Kerr–Newman(KN)black hole with a constant velocity along the polar axis is studied within the second post-Minkowskian(PM)ap...The gravitational deflection of light signals restricted in the polar-axis plane of a moving Kerr–Newman(KN)black hole with a constant velocity along the polar axis is studied within the second post-Minkowskian(PM)approximation.For this purpose,the Lorentz boosting technique is adopted to obtain the exact metric of a moving KN black hole with an arbitrary constant velocity in Kerr–Schild coordinates for the first time.Based on the weak field limit of the exact metric,we then derive the equations of motion of test particles constrained in the polaraxis plane of a moving KN source whose velocity is along the polar axis and collinear with its angular momentum.An iterative technique is utilized subsequently in the calculations of the null deflection angle up to the 2PM order caused by the moving lens,and this deflection angle is found to be spin-independent.Finally,we discuss the influence of the motion of the lens on the gravitational deflection and estimate the possibility of detecting this kinematical effect.Our work might be helpful for future astronomical observations.展开更多
The injection of electrical charge from an electrode into organic semiconductors directly influences the performance of organic optoelectronic devices.However,our understanding of the mechanisms behind charge injectio...The injection of electrical charge from an electrode into organic semiconductors directly influences the performance of organic optoelectronic devices.However,our understanding of the mechanisms behind charge injection remains incomplete.In this study,we explored the hole injection from an indium tin oxide(ITO)electrode into a hole transport layer(HTL)by employing various organic interlayers(ILs)with different ionization potentials(IPs).It was demonstrated that using O_(2)plasma treatment onto an ITO surface and incorporating an interlayer(IL)with a higher IP between the ITO electrode and the HTL can substantially increase the hole current density.This improvement leads to the achievement of barrier-free injection and the establishment of space-charge-limited current.We propose two synergistic mechanisms of spatial electron tunneling that govern the injection characteristics:electron tunneling from the HTL across the IL to the electrode that establishes an electrostatic equilibrium with a zero-injection barrier and an electric-field-induced spatial tunneling effect that occurs during device operation with applying bias.This research offers a strategy to achieve spacecharge-limited hole current and provides an explanatory framework for understanding the underlying physics of charge injection.展开更多
基金supported by the International Partnership Program of the Chinese Academy of Sciences (Grant No.025GJHZ2023106GC)。
文摘Primordial black holes(PBHs) offer a compelling candidate for dark matter. The production of PBHs through well-tested and accepted physical processes is highly worthy of investigation. This work highlights the role of turbulences in the very early universe in sustaining intense and persistent fluctuations in energy or mass density,which could provide a natural mechanism for PBH formation in the primordial universe. We analyze the mass range and abundance of PBHs produced in the magnetohydrodynamic turbulence induced by the electroweak phase transition. Remarkably, we find that the mass range of the produced PBHs falls within the most viable“asteroid mass” window from the present-day observations, and within natural parameter regions their abundance can be sufficiently large. These findings suggest that PBHs produced during magnetohydrodynamic turbulence in the very early universe may comprise a dominant part of dark matter.
基金the Deanship of Research and Graduate Studies at King Khalid University for funding this work through Large Research Project under Grant No.RGP2/539/45。
文摘We assume exponential corrections to the entropy of 5D charged Ad S black hole solutions,which are derived within the framework of Einstein-Gauss-Bonnet gravity and nonlinear electrodynamics.Additionally,we consider two distinct versions of 5D charged Ad S black holes by setting the parameters q→0 and k→0(where q represents the charge,and k is the non-linear parameter).We investigate these black holes in the extended phase space,where the cosmological constant is interpreted as pressure,demonstrating the first law of black hole thermodynamics.The focus extends to understanding the thermal stability or instability,as well as identifying first and second-order phase transitions.This exploration is carried out through the analysis of various thermodynamic quantities,including heat capacity at constant pressure,Gibbs free energy(GFE),Helmholtz free energy(HFE),and the trace of the Hessian matrix.In order to visualize phase transitions,identify critical points,analyze stability and provide comprehensive analysis,we have made the contour plot of the mentioned thermodynamic quantities and observed that our results are very consistent.These investigations are conducted within the context of exponentially corrected entropies,providing valuable insights into the intricate thermodynamic behavior of these 5D charged Ad S black holes under different parameter limits.
基金supported by the National Natural Science Foundation of China(Grant Nos.12473001,11975072,11875102,11835009,and 11965013)the National SKA Program of China(Grant Nos.2022SKA0110200 and 2022SKA0110203)+1 种基金the National 111 Project(Grant No.B16009)supported by Yunnan High-level Talent Training Support Plan Young&Elite Talents Project(Grant No.YNWR-QNBJ-2018-181).
文摘The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the analysis of characteristic lines and crossover behaviors within the supercritical region.By making use of the free energy,we introduce three key thermodynamic quantities:scaled variance,skewness,and kurtosis.Our results demonstrate that the Widom line,associated with the maximal scaled variance,can effectively differentiate between small and large black hole-like subphases,each displaying distinct thermodynamic behaviors within the supercritical region.Furthermore,by utilizing quasinormal modes,we identify the Frenkel line,offering a dynamic perspective to distinguish between small and large black hole-like subphases.These contribute to a deeper comprehension of black hole subphases in the supercritical region,thus illuminating new facets of black hole thermodynamics.
基金supported by the National Natural Science Foundation of China(Grant Nos.11633001,11920101003,and 12205222 for S.H.)the Key Program of the National Natural Science Foundation of China(Grant No.12433001)+1 种基金the Strate-gic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23000000)the National Key Research and Development Program of China(Grant No.2021YFC2203001 for Z.C.Z.).
文摘The gravitational memory effect manifests gravitational nonlinearity,degenerate vacua,and asymptotic symmetries;its detection is considered challenging.We propose using a space-borne interferometer to detect memory signals from stellar-mass binary black holes(BBHs),typically targeted by ground-based detectors.We use DECIGO detector as an example.Over 5 years,DECIGO is estimated to detect approximately 2,036 memory signals(SNRs>3)from stellar-mass BBHs.Simulations used frequency-domain memory waveforms for direct SNR estimation.Predictions utilized a GWTC-3 constrained BBH population model(Power law+Peak mass,DEFAULT spin,Madau-Dickinson merger rate).The analysis used conservative lower merger rate limits and considered orbital eccentricity.The high detection rate stems from strong memory signals within DECIGO’s bandwidth and the abundance of stellar-mass BBHs.This substantial and conservative detection count enables statistical use of the memory effect for fundamental physics and astrophysics.DECIGO exemplifies that space interferometers may better detect memory signals from smaller mass binaries than their typical targets.Detectors in lower frequency bands are expected to find strong memory signals from∼10^(4)M⊙binaries.
基金supported by the National Postdoctoral Fellowship of the Science and Engineering Research Board(SERB),Department of Science and Technology(DST),Government of India,File No.PDF/2021/003491。
文摘The photon region surrounding a black hole is crucial for distant observers to receive the emitted spectrum from its vicinity.This paper investigates the optical features of a regular spinning antide Sitter(AdS)black hole.These kinds of black holes hold deviation parameter k,and the cosmological constant A including their mass M and spin a.The cosmological parameter depends on the curvature radius by A=-3/l~2.We investigate the structure of geodesics for unstable circular orbits of photons as observed by an observer at specific Boyer-Lindquist coordinates(r_(O),v_(O))in the region between the outer and cosmological horizon,so-called the domain of outer communication.Our investigations include the analysis of three observables from its shadow plot:the black hole shadow radius(R_(s)),the distortion of the black hole(δ_(s)),and shadow area A.With the help of these observables,we calculate the angular diameter of the apparent size of the shadow.The shadows cast by spinning regular spacetimes are smaller compared to those produced by rotating black holes in both general relativity and regular spacetimes.We also calculate the rate at which energy is emitted from the black hole.
文摘Elemental doping of BiVO_(4) crystal lattices effectively enhances carrier separation,thereby facilitating efficient photoelectrochemical water splitting.However,the positive effect of elementally induced lattice distortions on hole extraction has been neglected.Herein,the crystal lattice of BiVO_(4) is distorted by doping with an inexpensive Cs metal;then,CoFe_(2)O_(4) is used as an efficient hole-extraction layer to further modify the surface of the doped photoanode.Benefiting from the above design,the newly prepared CoFe_(2)O_(4)-Cs-BiVO_(4) photoanode achieved a photocurrent density of 5.66 mA cm^(–2) at 1.23 V vs.a reversible hydrogen electrode,indicating a 3.9-fold improvement in photocurrent density.Detailed physicochemical characterization and density functional theory calculations showed that the lattice distortion induced by Cs doping promoted the directional migration of BiVO_(4) bulk-phase holes to the CoFe_(2)O_(4) layer.Additionally,the coupled CoFe_(2)O_(4) can be used as a hole extraction layer to further enhance the interfacial migration of carriers.The synergistic effect of the two effectively promotes the directional migration of photogenerated carriers from the BiVO_(4) bulk phase to the active sites of the oxygen evolution reaction,thereby effectively inhibiting carrier recombination.This study revealed the positive effect of the dual-hole extraction strategy on solar energy conversion,thereby opening new avenues for the rational design of photoanodes.
文摘In this work,the influences of surface layer slurry at different temperatures(10℃,14℃,18℃,22℃)on wax patterns deformation,shrinkage,slurry coating characteristics,and the surface quality of the casting were investigated by using a single factor variable method.The surface morphologies of the shell molds produced by different temperatures of the surface(first)layer slurries were observed via electron microscopy.Furthermore,the microscopic composition of these shell molds was obtained by EDS,and the osmotic effect of the slurry on the wax patterns at different temperatures was also assessed by the PZ-200 Contact Angle detector.The forming reasons for the surface cracks and holes of thick and large ZTC4 titanium alloy by investment casting were analyzed.The experimental results show that the surface of the shell molds prepared by the surface layer slurry with a low temperature exhibits noticeable damage,which is mainly due to the poor coating performance and the serious expansion and contraction of wax pattern at low temperatures.The second layer shell material(SiO_(2),Al_(2)O_(3))immerses into the crack area of the surface layer,contacts and reacts with the molten titanium to form surface cracks and holes in the castings.With the increase of the temperature of surface layer slurry,the damage to the shell surface tends to weaken,and the composition of the shell molds'surface becomes more uniform with less impurities.The results show that the surface layer slurry at 22℃is evenly coated on the surface of the wax patterns with appropriate thickness,and there is no surface shell mold rupture caused by sliding slurry after sand leaching.The surface layer slurry temperature is consistent with the wax pattern temperature and the workshop temperature,so there is no damage of the surface layer shell caused by expansion and contraction.Therefore,the shell mold prepared by the surface layer slurry at this temperature has good integrity,isolating the contact between the low inert shell material and the titanium liquid effectively,and the ZTC4 titanium alloy cylinder casting prepared by this shell mold is smooth,without cracks and holes.
基金National Natural Science Foundation of China under Grant Nos.52078386 and 52308496SINOMACH Youth Science and Technology Fund under Grant No.QNJJ-PY-2022-02+2 种基金Young Elite Scientists Sponsorship Program under Grant No.BYESS2023432Fund of State Key Laboratory of Precision Blasting and Hubei Key Laboratory of Blasting Engineering,Jianghan University under Grant No.PBSKL2023A9Fund of China Railway Construction Group Co.,Ltd.under Grant No.LX19-04b。
文摘Strong surface impact will produce strong vibration,which will pose a threat to the safety of nearby buried pipelines and other important lifeline projects.Based on the verified numerical method,a comprehensive numerical parameter analysis is conducted on the key influencing factors of the vibration isolation hole(VIH),which include hole diameter,hole net spacing,hole depth,hole number,hole arrangement,and soil parameters.The results indicate that a smaller ratio of net spacing to hole diameter,the deeper the hole,the multi-row hole,the hole adoption of staggered arrangements,and better site soil conditions can enhance the efficiency of the VIH barrier.The average maximum vibration reduction efficiency within the vibration isolation area can reach 42.2%.The vibration safety of adjacent oil pipelines during a dynamic compaction projection was evaluated according to existing standards,and the measurement of the VIH was recommended to reduce excessive vibration.The single-row vibration isolation scheme and three-row staggered arrangement with the same hole parameters are suggested according to different cases.The research findings can serve as a reference for the vibration safety analysis,assessment,and control of adjacent underground facilities under the influence of strong surface impact loads.
基金financially supported by the National Key Technology R&D Program of China(No.2021YFB3500801)
文摘Enhancing the activity of photocatalysts is a critical challenge for improving the photocatalytic degradation of contaminated wastewater.Here,a novel Ce single-atom-doped titanate nanotube photocatalyst(CeH_(2)Ti_(2)O_(5)·H_(2)O)was successfully synthesized using a onepot solvothermal method.Degradation experiments revealed that the optimal Ce doping ratio was 1.0%.The ultraviolet-visible diffuse reflectance spectroscopy results showed that the bandgap of the Ce-doped sample decreased from 3.02 to 2.87 eV,enhancing the absorption in the visible spectral range.At the same time,the BrunauerEmmett-Teller specific surface area increased from 63.68 to 88.95 m^(2)g^(-1).The 1.0%Ce-H_(2)Ti_(2)O_(5)·H_(2)O(HTC_(1))could degrade 99.04%of 100 mg L-1rhodamine B(RhB)after 40 min of visible-light irradiation.The degradation efficiency decreased by only 21.24%after five cycles.The results of free-radical quenching and electron spin resonance spectroscopy analyses indicated that HTC_(1)achieved efficient degradation of RhB through a direct hole oxidation mechanism.Compared with pure protonated titanate nanotubes(H_(2)Ti_(2)O_(5)·H_(2)O),HTC_(1)had a higher specific surface area,more electron traps,narrower bandgap,longer hole lifetime,and suppressed photogenerated charge recombination rate owing to the Ce single-atom doping.
基金financially supported by the CITIC niobium steel development award Fund(M1656-2021)Central Iron and Steel Research Institute for its independent research and development fund(No.21G62460ZD).
文摘Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb,respectively.The effects of microstructure,texture,crack propagation behavior and second phase precipitation behavior on hole expansion ratio were investigated.The precipitation behavior of TiC and(Ti,Nb)C in austenite and ferrite in three groups of steel samples was calculated theoretically.The results showed that the hole expansion ratios of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 51.73%,51.17%and 66.24%following simulated coiling at 600℃,respectively.The microstructure was mainly polygonal ferrite with a small amount of pearlite.The grain refinement of 0.097Ti–0.059Nb test steel and the low texture ratio of{110}//ND improved the hole expansion ratio.The low overall hole expansion ratio was due to the microstructure inhomogeneity.The microstructure uniformity was improved by the quenching and tempering treatment,and the hole expansion ratio of the three test steels was greatly increased.The fastest precipitation temperatures in the austenitic region of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 880,860 and 830℃,while those in the ferrite region were 680,675 and 675℃,respectively.The addition of Nb element increased the volume free energy,so that the critical core size of the nucleation on the dislocation line increased,resulting in the decrease in the fastest precipitation temperature.
基金supported by the financial support from the National Natural Science Foundation of China(Nos.22279046,22179053)Natural Science Excellent Youth Foundation of Jiangsu Province(No.BK20220112)Special Foundation for Carbon Peak Carbon Neutralization Technology Innovation Program of Jiangsu Province(No.BE2022026-2).
文摘Heterocyclic compounds play an important role in organic hole transport materials(HTMs)for perovskite solar cells(PSCs).Herein,a series of linear D-π-D HTMs(O-CBz,S-CBz,SO_(2)-CBz)with different dibenzoheterocycles core(dibenzofuran,dibenzothiophene,dibenzothiophene sulfone)were designed and synthesized,and their applications in PSCs were investigated.The intrinsic properties(CV,UV-vis,hole mobility and conductivity)were systematically investigated,demonstrating that all three materials are suitable HTMs for planar n-i-p type PSCs.Benefiting from the excellent hole mobility and conductivity,good film forming ability,and outstanding charge extraction and transport capability of S-CBz,FAPbI_(3)-based PSCs using S-CBz as HTM achieved a PCE of 25.0%,which is superior to that of Spiro-OMeTAD-based PSCs fabricated under the same conditions(23.9%).Furthermore,due to the interaction between S and Pb^(2+),SCBz-based PSC devices exhibited improved stability.This work demonstrates that dibenzothiophene-based architectures are promising candidates for high-performance HTMs in perovskite solar cell architectures.
基金supported by the National Natural Science Foundation of China[52475096]Guangxi Natural Science Fund for Distinguished Young Scholars[2025GXNSFFA069009]+2 种基金Bagui Outstanding Youth Program of Guangxi,ChinaNatural Science and Technology Innovation Development Doubling Plan Project of Guangxi University,China[2024BZRC010]Innovation Project of Guangxi Graduate Education,China[YCBZ2025014].
文摘The level set method(LSM)is renowned for producing smooth boundaries and clear geometric representations,facilitating integration with CAD environments.However,its inability to autonomously generate new holes during optimization makes the results highly dependent on the initial design.Although topological derivatives are often introduced to enable hole nucleation,their conversion into effective shape derivatives remains challenging,limiting topological evolution.To address this,a level set topology optimization method with autonomous hole formation(LSM-AHF)is proposed,integrating the material removal mechanism of the SIMP(Solid Isotropic Material with Penalization)method into the LSM framework.First,an initial structure is generated by adjusting the judgment threshold,and a binary thresholding algorithm is subsequently employed to obtain a clear and well-defined geometry.The structural boundaries of this geometry are then identified and used to construct a signed distance field,which serves as the initial level set function.To ensure smooth transitions across material interfaces and enhance numerical stability,Gaussian filtering is subsequently applied to the distance field.Numerical results demonstrate that LSMAHF effectively enables hole nucleation without manual initialization and improves topology change,addressing the respective limitations of conventional LSM and SIMP methods.
基金co-supported by the Basic Research for National Science and Technology Major Project of China(No. J2019-I-0012)the National Natural Science Foundation of China (No. 12102478)the Natural Science Basic Research Program Youth Project of Shaanxi Province,China (No.2021JQ-356)
文摘A film hole arrangement guideline along the temperature difference is proposed.The performance of different film holes arrangement and the impact of parameters are investigated though cascade wind tunnel test and numerical simulations.Finally,the optimized flow field structure and the mechanism of its effects are explored.Under the same operating conditions,Hole pattern#2(arrangement along the 50 K temperature difference line)can reduce coolant consumption by half while achieves the same cooling effect as original film hole arrangement.Additionally,Hole pattern#2 reduces the temperature difference between the suction and pressure sides of the vane,effectively protecting the structural strength.At mass flow ratio is 6.23%,Hole pattern#2 achieves both good cooling effectiveness and relatively saves coolant consumption,offering the highest costeffectiveness.The modulation in the position of film holes results in different local pressures affecting the flow inside the cooling chamber.The coupling of internal and external flows leads to different vortex structures near the outlet of the film holes,thereby influencing the film effectiveness.Hole pattern#2 does not exhibit significant high-cooling regions,but it shows a more uniform distribution of overall cooling effectiveness.Therefore,optimizing the arrangement of film holes and spacing them along the temperature difference is considered a crucial technical means to enhance the efficiency of gas turbines.
基金supported by the Ningbo Major Research and Development Plan Project(Grant No.2024Z135)the Natural Science Basic Research Program of Shaanxi Province(Grant No.2024JC-YBMS-322)+1 种基金China Postdoctoral Science Foundation(Grant No.2020M673492)National Natural Science Foundation of China(Grant No.51909219)。
文摘In this paper,a type of reinforcing structure for composite shell with single and through hole is presented.The experimental tests for the composite shells without hole,with single hole and reinforced structure,with through hole and reinforced structure subjected to hydrostatic pressure were carried out by the designed experimental test system.The mechanical responses of the composite shells under hydrostatic pressure are obtained by the high-speed camera and strain measurement.The results show that the entire deformation process of the shell can be divided into three:uniform compression,"buckling mode formation"and buckling.The"buckling mode formation"process is captured and reported for the first time.For the composite shell with single hole,the proposed reinforcing structure has a significant reinforcement effect on the shell and the buckling capacity of the shell is not weaker than the complete composite shell.For the composite shell with through hole,sealing effect can be achieved by the proposed reinforcing structure,but the buckling capacity of the shell after reinforcement can only reach 77%of the original buckling capacity.
基金the National Key Research and Development Program of China(No.2021YFB3400100)the National Natural Science Foundation of China(Nos.52235003&U2241261)。
文摘This study introduces a novel approach for coupled aeroelastic analysis of panel subjected to supersonic airflow,utilizing Add-On Acoustic Black Hole(AABH)to mitigate panel flutter.Employing Galerkin's method to discretize aeroelastic equation of panel and leveraging finite element method to derive a reduced discrete model of AABH,this study effectively couples two substructures via interface displacement.Investigation into the interactive force highlights the modal effective mass,frequency discrepancy between oscillation and AABH mode,and modal damping ratio as critical factors influencing individual AABH mode in flutter suppression.The selection of effective AABH modes,closely linked to these factors,directly influences the accuracy of simulations.The results reveal that AABH notably enhances the panel's critical flutter boundary by14.6%,a significant improvement over the 3.6%increase afforded by equivalent mass.Furthermore,AABH outperforms both the tuned mass damper and nonlinear energy sink in flutter suppression efficacy.By adjusting the AABH's geometrical parameters to increase the accumulative modal effective mass within the pertinent frequency range,or choosing a suitable installation position for AABH,its performance in flutter suppression is further optimized.These findings not only underscore the AABH's potential in enhancing aeroelastic stability but also provide a foundation for its optimal design.
文摘In the aerospace field,hole burnishing enhancement plays an essential role in improving the service performance of load-bearing holes.To satisfy the assembly accuracy and strength requirements,the structure shape and surface integrity must be considered simultaneously during the enhancement process.The current manufacturing process of hole burnishing has a relatively weak balance between the structure shape and surface integrity;therefore,it is necessary to analyze the mechanism and optimize the parameters to improve the strengthening effect of the holes.In this study,a two-dimensional longitudinal simplified model for the hole burnishing process was established,and the reasons for the surface roughness improvement of the hole wall and material accumulation on the upper surface were analyzed.Experiments were conducted to determine the influence of the burnishing parameters on the structure shape(material accumulation,shape contour,and roundness)and surface integrity(surface roughness,residual stress,and surface hardness),based on the opposite requirements of improving the structure shape and surface integrity for the burnishing depth(BD).The results showed that with an increase in the BD,the structure shape deteriorated,whereas the surface integrity improved.Fatigue behavior verification experiments were conducted,and parameter selection schemes for the collaborative improvement of the structure shape and surface integrity were discussed.For the holes of titanium alloy TB6(Ti-10V-2Fe-3Al),the fatigue life can be increased by 162%when the BD,spindle speed,and feed rate were 0.20 mm,200 r/min,and 0.2 mm/r,respectively.
文摘AIM:To evaluate whether fluid-air exchange is an effective treatment for unclosed macular hole(MH)after primary vitrectomy.METHODS:This retrospective study included patients with an unclosed MH within 1–2wk after vitrectomy.Patients were divided into the vitrectomy,fluid-air exchange,and observation groups according to the secondary treatment.The anatomical outcomes and postoperative visual acuity were recorded.RESULTS:The analysis included 25 eyes in 25 patients(16 females)aged 37–74y(vitrectomy group,n=10;fluid-air exchange group,n=9;observation group,n=6).Closure rate after secondary treatment was 100%in the vitrectomy group,88.9%in the fluid-air exchange group and 33.3%in the observation group.Optical coherence tomography images obtained at the last follow-up revealed that continuity of the external limiting membrane(ELM)was significantly more common(P=0.004)in the fluid-air group(8/9 eyes,88.9%)than in the vitrectomy group(2/10 eyes,20.0%)and that macular morphology was better in the fluid-air group than in the vitrectomy group.No serious complications were observed after secondary treatment.CONCLUSION:Fluid-air exchange is an alternative option to repeat vitrectomy for patients with an unclosed MH after initial vitrectomy with elevated macular edge.
文摘This study explores the dynamics of charged Hayward black holes,focusing on the effects of electric charge and the length factor on accretion disk characteristics.Our results show that increasing both parameters reduces the size of the event horizon and innermost stable circular orbits(ISCO)radius,with the electric charge exerting a more pronounced influence.Additionally,the length factor and electric charge can effectively replicate the spin of a Kerr black hole.Both parameters also affect the electromagnetic radiation emitted from the accretion disk,increasing the flux,temperature,and radiative efficiency.The peak radiation occurs in the soft x-ray band,with higher values of electric charge and length factor enhancing disk luminosity and shifting the peak to higher frequencies.These findings can offer valuable insights into the accretion processes around black holes and their observable signatures,particularly in x-ray astronomy.
基金supported in part by the National Natural Science Foundation of China(grant Nos.11973025,12205139,12303079,12475057,and 12481540180)the Natural Science Foundation of Hunan Province(grant No.2022JJ40347)。
文摘The gravitational deflection of light signals restricted in the polar-axis plane of a moving Kerr–Newman(KN)black hole with a constant velocity along the polar axis is studied within the second post-Minkowskian(PM)approximation.For this purpose,the Lorentz boosting technique is adopted to obtain the exact metric of a moving KN black hole with an arbitrary constant velocity in Kerr–Schild coordinates for the first time.Based on the weak field limit of the exact metric,we then derive the equations of motion of test particles constrained in the polaraxis plane of a moving KN source whose velocity is along the polar axis and collinear with its angular momentum.An iterative technique is utilized subsequently in the calculations of the null deflection angle up to the 2PM order caused by the moving lens,and this deflection angle is found to be spin-independent.Finally,we discuss the influence of the motion of the lens on the gravitational deflection and estimate the possibility of detecting this kinematical effect.Our work might be helpful for future astronomical observations.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFB0408000)Guangdong Provincial Department of Science and Technology(Grant No.2019TQ05C778)Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515011639)。
文摘The injection of electrical charge from an electrode into organic semiconductors directly influences the performance of organic optoelectronic devices.However,our understanding of the mechanisms behind charge injection remains incomplete.In this study,we explored the hole injection from an indium tin oxide(ITO)electrode into a hole transport layer(HTL)by employing various organic interlayers(ILs)with different ionization potentials(IPs).It was demonstrated that using O_(2)plasma treatment onto an ITO surface and incorporating an interlayer(IL)with a higher IP between the ITO electrode and the HTL can substantially increase the hole current density.This improvement leads to the achievement of barrier-free injection and the establishment of space-charge-limited current.We propose two synergistic mechanisms of spatial electron tunneling that govern the injection characteristics:electron tunneling from the HTL across the IL to the electrode that establishes an electrostatic equilibrium with a zero-injection barrier and an electric-field-induced spatial tunneling effect that occurs during device operation with applying bias.This research offers a strategy to achieve spacecharge-limited hole current and provides an explanatory framework for understanding the underlying physics of charge injection.
