Semiconductor colloidal nanocrystals(NCs)have size-and shape-dependent optoelectronic properties due to the quantum confinement effect,and are considered to be promising optoelectronic materials.Among them,Ⅱ-Ⅵ(CdSe,...Semiconductor colloidal nanocrystals(NCs)have size-and shape-dependent optoelectronic properties due to the quantum confinement effect,and are considered to be promising optoelectronic materials.Among them,Ⅱ-Ⅵ(CdSe,CdS,CdTe,etc.)andⅣ-Ⅵ(PbSe,PbTe,PbS,etc.)have been widely studied as representative colloidal NCs.However,the surfactant used in its synthesis progress results in the NCs surface covered by an insulating shell,which greatly affects the exciton separation and carrier transport of colloidal NCs-based photovoltaic devices.Therefore,how to design high-efficiency optoelectronic devices by improving the transport performance of carriers has been a great challenge.The key issues in the research ofⅡ-Ⅵ(CdSe,CdS,CdTe,etc.)andⅣ-Ⅵ(PbSe,PbTe,PbS,etc.)colloidal NCs were summarized,including synthesis strategy,morphology/size adjustment,surface ligand design,improvement of conductivity and their optoelectronic properties.The influence of surface ligands on the stability and dispersion of NCs was firstly introduced,and then strategies of improving electrical conductivity of NCs were discussed,such as ligands exchange,doping,self-assembly and plasmons,which provided a good foundation for the subsequent preparation of optoelectronic devices.The future development direction of NCs optoelectronic devices is expounded from the aspects of materials composition,comprehensive preparation and flexible processing of colloidal NCs.展开更多
Based on the region model of lambda bipolar transistor ( LBT), a dividing region theory model of PLBT is set up,simulated and verified. Firstly, the principal operations of different kinds of photoelectronic lambda bi...Based on the region model of lambda bipolar transistor ( LBT), a dividing region theory model of PLBT is set up,simulated and verified. Firstly, the principal operations of different kinds of photoelectronic lambda bipolar transistor ( PLBT) are characterized by a simple circuit model. Through mathematical analysis of the equivalent circuit, the typical characteristics curve is divided into positive resistance, peak, negative resistance and cutoff regions. Secondly, by analyzing and simulating this model, the ratio of MOSFET width to channel length, threshold voltage and common emitter gain are discovered as the main structure parameters that determine the characteristic curves of PLBT. And peak region width, peak current value, negative resistance value and valley voltage value of PLBT can be changed conveniently according to the actual demands by modifying these parameters. Finally comparisons of the characteristics of the fabricated devices and the simu- lation results are made, which show that the analytical results are in agreement with the observed devices characteristics.展开更多
The growing interest in biological skin mimicry has greatly contributed to the creation of high-performance artificial skin.Here,inspired by the optical-electrical signal co-transmission of chameleon skins,a bilayer b...The growing interest in biological skin mimicry has greatly contributed to the creation of high-performance artificial skin.Here,inspired by the optical-electrical signal co-transmission of chameleon skins,a bilayer biomimetic ion-conductive photoelectronic skin(BIPES)was constructed by compositing the mechanochromic nano-structured silica photonic crystal film with an adhesive,flexible hydrogel by a layer-by-layer design strategy.The BIPES has a highly sensitive strain response on electrical and optical signals(GF=3.27 at 0-100%,△λ/△ε=2.1 nm%^(-1))and temperature response(TCR=-2.27%℃^(-1)at 0-50℃).Importantly,through the temperature insensitivity of the mechanochromic film,the BIPES not only achieved dual-signal motion detection but also achieved real-time temperature monitoring excluding strain interference.This research provides new inspiration for the construction of multi-signal combined photoelectronic skins and further exploration for advanced accurate smart wearable electronics in appli-cations,especially in health detection for patients with non-spontaneous body-trembling.展开更多
The development of large-area high-performance flexible photoelectronic synaptic devices has become a hot topic in the field of neuromorphic computing and artificial vision systems.In this work,we have successfully pr...The development of large-area high-performance flexible photoelectronic synaptic devices has become a hot topic in the field of neuromorphic computing and artificial vision systems.In this work,we have successfully prepared a large-area,ultra-flexible semiconducting single-walled carbon nanotubes(sc-SWCNTs)photoelectronic synaptic thin-film transistors(TFTs)array(33×34)using solution-processable AlO_(x)thin film as the dielectrics by roll-to-roll gravure printing.Our photoelectronic synaptic TFTs exhibit excellent electrical properties with high switching ratio(≥10^(5)),low subthreshold swing(73 mV·dec^(−1)),excellent photoresponse properties over a wide wavelength range(from 270 to 650 nm),sustained photoconductivity effect(only 26.7%drop after removing light source for 36,000 s)and remarkable mechanical reliability and flexibility(maintaining excellent electrical properties after bending more than 15,000 cycles with a bending radius of 5 mm).In addition,concepts such as multimodal optoelectronic synaptic plasticity,optical writing speed perception simulation,and human eye self-recovery model have been successfully demonstrated using printed flexible sc-SWCNTs photoelectronic neuromorphic TFTs arrays.More importantly,we systematically investigated the response characteristics of these devices under deep ultraviolet light stimulation and,for the first time,successfully simulated bio-inspired visual perception self-recovery including the dynamic transition of the visual system from clarity to blurriness and their self-recovery over time.This work indicates that our photoelectronic neuromorphic TFT devices have great practical potential in human-computer interaction,environment perception,and visual simulation.展开更多
Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent...Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent bonds and the limited modifiability of COFs with irreversible covalent bonds restricted the enhancement of the pCO_(2)RR performance.Herein,three phthalocyanine-based COFs with ether-linked,CoOP,CoPOP,and CoBOP,were successfully prepared via in situ polycondensation using modifiable bis-phthalonitrile.CoBOP achieved a record of syngas performance in pCO_(2)RR systems with photosensitizers and sacrificial agents(CO 83.7 mmol g^(-1)h^(-1)and H_254.7 mmol g^(-1)h^(-1)),surpassing most COF photocatalysts.Additionally,CoOP,CoPOP,and CoBOP exhibit stabilities in extreme environments owing to their irreversible covalent bonds.Experimental and density functional theory analyses confirm that the optimally matched the lowest unoccupied molecular orbital of the linking unit between the photosensitizer and active unit endowed Co BOP with the highest photoelectron transfer efficiency among the three catalysts,boosting its pCO_(2)RR activity.This work is highly instructive for designing COFs with structure-adjustable and irreversible covalent bonds.展开更多
Medical implants with functionalities such as sensing,health monitoring,stimulation,diagnosis,and physiological treatment are rapidly growing.With the increasing functional sophistication and addition of modules such ...Medical implants with functionalities such as sensing,health monitoring,stimulation,diagnosis,and physiological treatment are rapidly growing.With the increasing functional sophistication and addition of modules such as data transmission,on-chip processing,and data storage,energy demand of the implantable system is also growing.Using implantable energy harvester either to recharge or ultimately replace hazardous battery is essential to provide a long-term sustainable solution.Energy harvesting techniques using piezoelectric,thermoelectric,radio frequency power transmission,biofuel,and photoelectronic(or sometimes termed as“photovoltaic”in terms of solar light harvesting,i.e.,PV)conversion,have been attempted for the implantable,but these methods are currently limited by insufficient power output,large footprint,and low efficiency.Nevertheless,the planar PV with potential of lighter weight,higher energy density,and higher efficiency,provides promising power solution for in-body medical implants.In this short review,we will discuss the potential opportunities and challenges associated with PV's for medical implants,covering materials,to devices,and to system level requirements.展开更多
Understanding the dynamics of photoexcited carriers is essential for advancing photoelectronic device design.Photon absorption generates electron–hole pairs,and subsequent scatterings can induce ultrafast thermalizat...Understanding the dynamics of photoexcited carriers is essential for advancing photoelectronic device design.Photon absorption generates electron–hole pairs,and subsequent scatterings can induce ultrafast thermalization within a picosecond,forming a quasi-equilibrium distribution with overheated electrons.The high-energy tail of this distribution enables carriers to overcome energy barriers,thereby enhancing quantum efficiency—a phenomenon known as photothermionic emission(PTE).Despite its importance,the onset and mechanisms of PTE remain under debate.Using real-time timedependent density functional theory(rt-TDDFT),we investigate ultrafast carrier thermalization in two-dimensional(2D)materials graphene and PtTe2,and the results reveal distinct differences.In graphene,both electrons and holes thermalize into Fermi–Dirac distributions with good agreement to experiment,while PtTe2exhibits anomalous high-energy tails for both electrons and holes,deviating significantly from Fermi–Dirac behavior.We attribute this anomaly to differences in orbital coupling between the two materials,from which we derive design principles for identifying optimal PTE candidates and,ultimately,improving photodetector performance.展开更多
We report a study on the electronic structure and chemical bonding of the PB and AsB diatomic molecules using high-resolution photoelectron imaging of cryogenically-cooled PB^(−)and AsB^(−)anions.The electron affiniti...We report a study on the electronic structure and chemical bonding of the PB and AsB diatomic molecules using high-resolution photoelectron imaging of cryogenically-cooled PB^(−)and AsB^(−)anions.The electron affinities of PB and AsB are measured to be 2.751(1)and 2.600(1)eV,respectively.The ground states of the PB^(−)and AsB−anions are determined to be ^(2)Σ^(+) with a σ^(1)π^(4) valence electron configuration.The ground states of neutral PB and AsB are found to be ^(3)Π_(2) with a σ^(1)π^(3) electron configuration.The spin-orbit excited states(^(3)Π_(1) and ^(3)Π_(0)),as well as two low-lying singlet excited states(^(1)Σ^(+)and ^(1)Π),are observed.Unusual spectroscopic characteristics are observed in the ^(3)Π_(2) ground state of AsB,probably due to state mixing with a higher-lying ^(1)Δ_(2) state.The current work provides extensive electronic and spectroscopic information for the PB and AsB molecules.展开更多
Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ra...Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ray Photoelectron emission spectroscopy(HAXPES)and microscopy(HAXPEEM)as well as microscopic X-ray absorption spectroscopy(μ-XAS)techniques.The results reveal the inhomogeneity in the oxide films on the micron-sized Cr_(2)N-and VN-type particles,while the inhomogeneity on the martensite matrix phase exists due to localised formation of nano-sized tempering nitride particles at 600℃.The oxide film formed on Cr_(2)N-type particles is rich in Cr_(2)O_(3) compared with that on the martensite matrix and VN-type particles.With the increase of tempering temperature,Cr_(2)O_(3) formation is faster for the oxidation of Cr in the martensite matrix than the oxidation of Cr nitride-rich particles.展开更多
Magnesium alloys as medical implant materials necessitate a lower and adjustable corrosion rate for clinical applications.The microstructure and corrosion behavior of AZ31Mn-xEr(x=0.1,0.5,1.2)alloys were systematicall...Magnesium alloys as medical implant materials necessitate a lower and adjustable corrosion rate for clinical applications.The microstructure and corrosion behavior of AZ31Mn-xEr(x=0.1,0.5,1.2)alloys were systematically investigated using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray photoelectron spectroscopy(XPS),combined with Tafel polarization and electrochemical impedance spectroscopy(EIS)analyses.The findings showed that the alloying element Er refined the grain structure during solidification by increasing the nucleation rate and forming a secondary phase of Al_(3)Er with Al.The Er and Mg in the matrix co-oxidize to form a dense MgO/Er_(2)O_(3)composite oxide,preventing the formation of loose magnesium hydroxide/basic magnesium carbonate.The trace alloying element Mn interacts with impurities Fe in the magnesium matrix to form an AlFeMn second phase,reducing micro-galvanic corrosion driving force.Electrochemical testing in a 3.5%NaCl solution demonstrated a marked reduction in corrosion rate from 10.46 mm/a(AZ 31 Mn alloy)to 0.44 mm/a(AZ31Mn-1.2Er alloy).This research offers a reference for searching for corrosion-resistant magnesium alloy and degradable medical magnesium alloy materials.展开更多
The corrosion behaviors of an as-cast FeCoNiAl_(0.75)Cr_(1.25)high-entropy alloy(HEA)in acidic Na_(2)SO_(4)solution with different pH values were investigated.The results indicate that the as-cast FeCoNiAl_(0.75)Cr_(1...The corrosion behaviors of an as-cast FeCoNiAl_(0.75)Cr_(1.25)high-entropy alloy(HEA)in acidic Na_(2)SO_(4)solution with different pH values were investigated.The results indicate that the as-cast FeCoNiAl_(0.75)Cr_(1.25)HEA is mainly composed of face-centered cubic phase,body-centered cubic(BCC1)phase(Co–Cr–Fe)and ordered BCC(B2)phase(Ni–Al),in which BCC1 phase and B2 phase have a eutectic microstructure.Moreover,the corrosion of B2 phase occurs preferentially in a 0.05 mol/L SO_(4)^(2−)acidic solution.The electrochemical measurement results show that the corrosion resistance of the investigated HEA significantly changes as the solution pH increases from 2 to 2.5.This indicates that there is a critical pH in the range of 2–2.5 that affects the corrosion of HEA.In addition,the results of X-ray photoelectron spectroscopy prove that the surface film of FeCoNiAl_(0.75)Cr_(1.25)in SO_(4)^(2−)solution is formed with Al_(2)O_(3)and Cr_(2)O_(3)as the main components,and The content of Al2O3 and Cr_(2)O_(3)increases with increasing solution pH.展开更多
In the present work,the effects of neodymium(Nd)on micro structure,mechanical performance,and corrosion behavior of powder metallurgy Mg-2Si-xNd(x=0.05 wt%,0.15 wt%,and 0.20 wt%)alloys were investigated.Microstructure...In the present work,the effects of neodymium(Nd)on micro structure,mechanical performance,and corrosion behavior of powder metallurgy Mg-2Si-xNd(x=0.05 wt%,0.15 wt%,and 0.20 wt%)alloys were investigated.Microstructures were examined by optical and scanning electron microscopes combined with an energy-dispersive spectrometer.Hardness and compressive tests were used to study the mechanical properties of alloys.Potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),Mott-Schottky analysis,and the hydrogen evolution test were applied to characterize the corrosion behavior of alloys in Hanks'solution.The microstructure of Mg-2Si-xNd alloys mainly consists ofα-Mg matrix,Mg2Si,and MgNd phases.The increase in Nd content tends to decrease the aspect ratio ofα-Mg grains,which leads to the enhancement of the ultimate-compressive strengths and hardness of the alloys.Potentiodynamic polarization shows that increasing Nd content leads to a lower corrosion current density in the Mg-2Si-xNd alloys.The EIS results confirm that a higher addition of Nd suppresses the dissolution kinetics of the alloys due to the increasing charge transfer resistance.Mott-Schottky analysis reveals the formation of an n-type semiconductive passive film on the alloy surfaces,where the interstitial and oxygen vacancies predominate over the metal vacancies.The X-ray photoelectron spectroscopy(XPS)reveals that a mixture of Mg(OH)_(2),MgO,MgCO_(3),and Nd_(2)O_(3)has formed as the corrosion products on the Mg-2Si-xNd alloy surfaces after a longer immersion time in Hanks'solution.展开更多
High-resolution photoelectron spectra of cryogenically cooled TiO_(2)CH_(3)OH^(−)anions obtained with slow electron velocity-map imaging are reported and used to explore the reactions of TiO_(2)^(−/0)with methanol.The...High-resolution photoelectron spectra of cryogenically cooled TiO_(2)CH_(3)OH^(−)anions obtained with slow electron velocity-map imaging are reported and used to explore the reactions of TiO_(2)^(−/0)with methanol.The highly structured spectra were compared with results from DFT calculations to determine the dominant structure to be cis-CH_(3)OTi(O)OH^(−),a dissociative adduct in which CH3OH is split by TiO_(2)^(−).The experiment yields an electron affinity of 1.2152(7)eV for TiO_(2)CH^(3)OH as well as several vibrational frequencies for the neutral species.Comparison to Franck−Condon(FC)simulations shows that while most experimental features appear in the simulations,several are not and are assigned to FC-forbidden transitions involving non-totally symmetric vibrational modes.The FC-allowed and forbidden transi-tions also exhibit different photoelectron angular distributions.The FC-forbidden transitions are attributed to Herzberg−Teller(HT)coupling with the A^(2)A″excited state of the anion.The results are compared to previous cryogenic slow electron velocity-map imaging(cryo-SE-Ⅵ)studies of bare TiO_(2)^(−)and the water-split adduct TiO_(3)H_(2)^(−).展开更多
The structure and electronic properties of Co_(2)Ge_(10)^(-)anion and its neutral counterpart were investigated by anion photoelectron spectroscopy and theoretical calculations.The experimental vertical detachment ene...The structure and electronic properties of Co_(2)Ge_(10)^(-)anion and its neutral counterpart were investigated by anion photoelectron spectroscopy and theoretical calculations.The experimental vertical detachment energy of Co_(2)Ge_(10)^(-)was measured to be 2.86±0.08 eV.The lowest-energy isomer of Co_(2)Ge_(10)^(-)is in a doublet state and has a cage-like structure with Cs symmetry,which can be constructed by a tetragonal bipyramid on top of a pentagonal bipyramid and these two bipyramid structures share a common Co atom.The most stable structure of neutral Co_(2)Ge_(10)resembles its anionic counterpart and it is in a triplet state.The natural population analysis showed that the inner Co atom of both the anionic and neutral Co_(2)Ge_(10)acquires negative charge from the neighboring Ge atoms.The outer Co atom has a larger spin moment than the inner Co atom,indicating that the magnetic moments of Co_(2)Ge_(10)^(-/0)are mainly contributed by the outer Co atom.Analyses of the density of states and molecular orbitals indicated that there are a few highly delocalized molecular orbitals in Co_(2)Ge_(10)^(-),which are mainly contributed by Ge 4s atomic orbitals.展开更多
MgATP is a stable complex formed by the chelation of Mg^(2+)with deprotonated adenosine-5'-triphosphate(ATP).In the cellular environment,MgATP plays a critical role in ATP hydrolysis,releasing substantial energy t...MgATP is a stable complex formed by the chelation of Mg^(2+)with deprotonated adenosine-5'-triphosphate(ATP).In the cellular environment,MgATP plays a critical role in ATP hydrolysis,releasing substantial energy to support essential biological functions.To understand the structure and stabilization mechanism of MgATP,we conducted a joint negative ion photoelectron spectroscopic and computational study of the[ATP^(4-)·Mg^(2+)]^(2-)complex dianion,using[ATP^(4-)·2H^(+)]^(2-)as a reference.The experimentally determined adiabatic and vertical detachment energies(ADE and VDE)of[ATP^(4-)·Mg^(2+)]^(2-)at 20 K are 3.51±0.05 eV and 3.82±0.05 eV,respectively.The major spectral features of[ATP^(4-)·Mg^(2+)]^(2-)are attributed to two theoretically identified isomers with unfolded geometries,which are stabilized primarily by electrostatic interactions between Mg^(2+)and the triphosphate and ribose groups,with four deprotonated oxygens forming a pseudo-tetrahedral coordination.In contrast,[ATP^(4-)·2H^(+)]^(2-)exhibits a fundamentally different stabilization mechanism.Although most of the fifteen identified[ATP^(4-)·2H^(+)]^(2-)isomers also adopt unfolded geometries,they are primarily stabilized by intramolecular hydrogen bonds within the triphosphate group and between triphosphate and ribose groups.The interaction between ATP^(4-)and two protons is found to be much weaker than that with Mg^(2+),and[ATP^(4-)·2H^(+)]^(2-)exhibits substantial structural flexibility compared to[ATP^(4-)·Mg^(2+)]^(2-)due to the conformational constraint of the triphosphate chain by Mg^(2+).Thirteen[ATP^(4-)·2H^(+)]^(2-)isomers with unfolded geometries likely account for the major high-EBE(electron-binding-energy)spectral features.Notably,for the first time,a low EBE and temperature-dependent spectral feature is observed and attributed to two folded isomers of[ATP^(4-)·2H^(+)]^(2-),which exist at 20 K but disappear at room temperature.This study provides valuable molecular-level insights into cellular MgATP that resides within the hydrophobic pockets of proteins.展开更多
The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(...The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(2)(M=Ti,Zr,and Hf)compounds are formed in bent insertion structures.The observed ground-state adiabatic detachment energy(ADE)is measured to be 1.597±0.003,1.651±0.003,and 2.119±0.003 eV for TiO_(2)^(-),ZrO_(2)^(-),and HfO_(2)^(-),respectively.The vibrational frequencies of the anionic and neutral MO_(2)are also determined from the experimental spectra.The results of theoretical calculations show that the electronic configurations of MO_(2)^(-)are^(2)A_(1)with C_(2v)point group.Bond order analysis indicates that the two M-O bonds are all multiple characters.展开更多
The corrosion behavior of CoCrCu_(0.1)FeMoNi high entropy alloy(HEA)in 0.5 mol/L NaOH solution was investigated using X-ray photoelectron spectroscopy,X-ray diffraction,scanning electron microscopy,potentiodynamic pol...The corrosion behavior of CoCrCu_(0.1)FeMoNi high entropy alloy(HEA)in 0.5 mol/L NaOH solution was investigated using X-ray photoelectron spectroscopy,X-ray diffraction,scanning electron microscopy,potentiodynamic polarization measurement,and electrochemical impedance spectroscopy.The results showed that the microstructure of this HEA displayed a dendritic morphology along with inter-dendritic regions.At the applied potential of–0.3,0,and 0.1 V vs.saturated calomel electrode(SCE),no significant damage to the surface of the alloy was observed.At the applied potentials of 0.15 and 0.2 V vs.SCE,selective detachment and tearing of the microstructure on the alloy surface were observed,attributed to micro-galvanic corrosion.HEA demonstrates typical spontaneous passivation behavior and exhibits capacitance at all five applied potentials.The energy dispersive spectroscopy results indicate significant elemental segregation within HEA,with a decrease in the content of Cr_(2)O_(3)in the passive film as the applied potential increases.Consequently,the protective efficacy of the passive film over the substrate in 0.5 mol/L NaOH solution was compromised.展开更多
Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneit...Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneity due to the degradation of Mg on its corrosion behavior.The immersion experiments using pure Mg plates,which were placed vertically in a culture medium(Dulbecco’s Modified Eagle’s Medium(DEME)+10%fetal bovine serum(FBS))for 1,5,and 10 days,were conducted.Surface analyses for the corrosion product layers and the measurements of the pH values and concentrations of eluted ions in the immersion medium around the upper and lower areas of the Mg plate were performed.The significant effect of the macroscopic environmental heterogeneity derived from Mg degradation on the corrosion behavior was demonstrated by in vitro tests.Additionally,the in vivo tests were carried out by implanting the pure Mg plates in the femur of rabbits.The in vivo results exhibited macroscopically heterogeneous Mg degradation,with areas of more severe corrosion compared to the in vitro test;it is especially noticeable during the early stage of degradation,even though the average corrosion rate was lower.展开更多
We have performed a comparative study of the photoelectron spectra adopting different initial states(2s or 2_(p0))of hydrogen atoms in a near-infrared laser pulse by using the full three-dimensional time-dependent Sch...We have performed a comparative study of the photoelectron spectra adopting different initial states(2s or 2_(p0))of hydrogen atoms in a near-infrared laser pulse by using the full three-dimensional time-dependent Schr?dinger equation.It is demonstrated that the atomic photoelectron spectra oscillate out of step as a function of electron kinetic energies for different initial states(2s or 2_(p0)),which is well reproduced by the simulations based on strong field approximation,and the above distinct feature is ascribed to the different interferences from the partial electron wave packets detached by positive and negative electric fields for different initial states of 2s and 2_(p0).展开更多
In order to investigate the effect of different doping types on the band alignment of heterojunctions,we prepared PtSe_(2)/n-GaN,PtSe_(2)/p-GaN,and PtSe_(2)/u-GaN heterojunctions by wet transfer technique.The valence ...In order to investigate the effect of different doping types on the band alignment of heterojunctions,we prepared PtSe_(2)/n-GaN,PtSe_(2)/p-GaN,and PtSe_(2)/u-GaN heterojunctions by wet transfer technique.The valence band offsets(VBO)of the three heterojunctions were measured by x-ray photoelectron spectroscopy(XPS),while the PtSe_(2)/n-GaN is 3.70±0.15 eV,PtSe_(2)/p-GaN is 0.264±0.15 eV,and PtSe_(2)/u-GaN is 3.02±0.15 eV.The conduction band offset(CBO)of the three heterojunctions was calculated from the material bandgap and VBO,while the PtSe_(2)/n-GaN is 0.61±0.15 eV,PtSe_(2)/p-GaN is 2.83±0.15 eV,and PtSe_(2)/u-GaN is 0.07±0.15 eV.This signifies that both PtSe_(2)/u-GaN and PtSe_(2)/p-GaN exhibit type-Ⅰband alignment,but the PtSe_(2)/n-GaN heterojunction has type-Ⅲband alignment.This signifies that the band engineering of PtSe_(2)/GaN heterojunction can be achieved by manipulating the concentration and type of doping,which is significantly relevant for the advancement of related devices through the realization of band alignment and the modulation of the material properties of the PtSe_(2)/GaN heterojunction.展开更多
基金supported by the National Natural Science Foundation of China(No.51976081)。
文摘Semiconductor colloidal nanocrystals(NCs)have size-and shape-dependent optoelectronic properties due to the quantum confinement effect,and are considered to be promising optoelectronic materials.Among them,Ⅱ-Ⅵ(CdSe,CdS,CdTe,etc.)andⅣ-Ⅵ(PbSe,PbTe,PbS,etc.)have been widely studied as representative colloidal NCs.However,the surfactant used in its synthesis progress results in the NCs surface covered by an insulating shell,which greatly affects the exciton separation and carrier transport of colloidal NCs-based photovoltaic devices.Therefore,how to design high-efficiency optoelectronic devices by improving the transport performance of carriers has been a great challenge.The key issues in the research ofⅡ-Ⅵ(CdSe,CdS,CdTe,etc.)andⅣ-Ⅵ(PbSe,PbTe,PbS,etc.)colloidal NCs were summarized,including synthesis strategy,morphology/size adjustment,surface ligand design,improvement of conductivity and their optoelectronic properties.The influence of surface ligands on the stability and dispersion of NCs was firstly introduced,and then strategies of improving electrical conductivity of NCs were discussed,such as ligands exchange,doping,self-assembly and plasmons,which provided a good foundation for the subsequent preparation of optoelectronic devices.The future development direction of NCs optoelectronic devices is expounded from the aspects of materials composition,comprehensive preparation and flexible processing of colloidal NCs.
基金Supported by "973" National Key Basic Research Program ( No. 2002CB311905).
文摘Based on the region model of lambda bipolar transistor ( LBT), a dividing region theory model of PLBT is set up,simulated and verified. Firstly, the principal operations of different kinds of photoelectronic lambda bipolar transistor ( PLBT) are characterized by a simple circuit model. Through mathematical analysis of the equivalent circuit, the typical characteristics curve is divided into positive resistance, peak, negative resistance and cutoff regions. Secondly, by analyzing and simulating this model, the ratio of MOSFET width to channel length, threshold voltage and common emitter gain are discovered as the main structure parameters that determine the characteristic curves of PLBT. And peak region width, peak current value, negative resistance value and valley voltage value of PLBT can be changed conveniently according to the actual demands by modifying these parameters. Finally comparisons of the characteristics of the fabricated devices and the simu- lation results are made, which show that the analytical results are in agreement with the observed devices characteristics.
基金financially supported by the National Natural Science Foundation of China(No.82172040).
文摘The growing interest in biological skin mimicry has greatly contributed to the creation of high-performance artificial skin.Here,inspired by the optical-electrical signal co-transmission of chameleon skins,a bilayer biomimetic ion-conductive photoelectronic skin(BIPES)was constructed by compositing the mechanochromic nano-structured silica photonic crystal film with an adhesive,flexible hydrogel by a layer-by-layer design strategy.The BIPES has a highly sensitive strain response on electrical and optical signals(GF=3.27 at 0-100%,△λ/△ε=2.1 nm%^(-1))and temperature response(TCR=-2.27%℃^(-1)at 0-50℃).Importantly,through the temperature insensitivity of the mechanochromic film,the BIPES not only achieved dual-signal motion detection but also achieved real-time temperature monitoring excluding strain interference.This research provides new inspiration for the construction of multi-signal combined photoelectronic skins and further exploration for advanced accurate smart wearable electronics in appli-cations,especially in health detection for patients with non-spontaneous body-trembling.
基金supported by the National Key Research and Development Program of China(No.2020YFA0714700)the National Natural Science Foundation of China(Nos.62274174 and 52173192)+2 种基金Basic Research Program of Jiangsu(No.BK20232009)a fellowship from the China Postdoctoral Science Foundation(NO.2023M742559)the Cooperation Project of Vacuum Interconnect Research Facility(NANO-X)of Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(No.F2208).
文摘The development of large-area high-performance flexible photoelectronic synaptic devices has become a hot topic in the field of neuromorphic computing and artificial vision systems.In this work,we have successfully prepared a large-area,ultra-flexible semiconducting single-walled carbon nanotubes(sc-SWCNTs)photoelectronic synaptic thin-film transistors(TFTs)array(33×34)using solution-processable AlO_(x)thin film as the dielectrics by roll-to-roll gravure printing.Our photoelectronic synaptic TFTs exhibit excellent electrical properties with high switching ratio(≥10^(5)),low subthreshold swing(73 mV·dec^(−1)),excellent photoresponse properties over a wide wavelength range(from 270 to 650 nm),sustained photoconductivity effect(only 26.7%drop after removing light source for 36,000 s)and remarkable mechanical reliability and flexibility(maintaining excellent electrical properties after bending more than 15,000 cycles with a bending radius of 5 mm).In addition,concepts such as multimodal optoelectronic synaptic plasticity,optical writing speed perception simulation,and human eye self-recovery model have been successfully demonstrated using printed flexible sc-SWCNTs photoelectronic neuromorphic TFTs arrays.More importantly,we systematically investigated the response characteristics of these devices under deep ultraviolet light stimulation and,for the first time,successfully simulated bio-inspired visual perception self-recovery including the dynamic transition of the visual system from clarity to blurriness and their self-recovery over time.This work indicates that our photoelectronic neuromorphic TFT devices have great practical potential in human-computer interaction,environment perception,and visual simulation.
基金financially supported by the Innovation Capability Support Program of Shaanxi—Science and Technology Innovation Team Project(No.2025RS-CXTD-024)the Fundamental Research Foundation of SHCCIG New Materials Technology Research Institute Co.,Ltd(No.D5204230171)+3 种基金the Fundamental Research Funds for the Central Universities(G2025KY05240)the Natural Science Basic Research Program of Shaanxi(Program No.2024JC-YBQN-0073)the Fundamental Research Funds for the Central Universities(No.D5000250204)Young Talent Fund of Association for Science and Technology in Shaanxi(No.20230101)。
文摘Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent bonds and the limited modifiability of COFs with irreversible covalent bonds restricted the enhancement of the pCO_(2)RR performance.Herein,three phthalocyanine-based COFs with ether-linked,CoOP,CoPOP,and CoBOP,were successfully prepared via in situ polycondensation using modifiable bis-phthalonitrile.CoBOP achieved a record of syngas performance in pCO_(2)RR systems with photosensitizers and sacrificial agents(CO 83.7 mmol g^(-1)h^(-1)and H_254.7 mmol g^(-1)h^(-1)),surpassing most COF photocatalysts.Additionally,CoOP,CoPOP,and CoBOP exhibit stabilities in extreme environments owing to their irreversible covalent bonds.Experimental and density functional theory analyses confirm that the optimally matched the lowest unoccupied molecular orbital of the linking unit between the photosensitizer and active unit endowed Co BOP with the highest photoelectron transfer efficiency among the three catalysts,boosting its pCO_(2)RR activity.This work is highly instructive for designing COFs with structure-adjustable and irreversible covalent bonds.
基金supported by the U.S.Department of Energy's Office of Energy Efficiency and Renewable Energy(EERE)under the Solar Energy Technologies Office Award Number DE-EE0009364K.W.acknowledges the support from U.S.DOE EERE under the Solar Energy Technologies Office award number DE-EE0009364.S.P+1 种基金the support through DOE STTR program(Prime-NanoSonic Inc.),DE-SC0019844.S.K.Kthe support from U.S.Department of Agriculture-National Institute of Food and Agriculture(USDA-NIFA),under Award No.2019-67021-28991.
文摘Medical implants with functionalities such as sensing,health monitoring,stimulation,diagnosis,and physiological treatment are rapidly growing.With the increasing functional sophistication and addition of modules such as data transmission,on-chip processing,and data storage,energy demand of the implantable system is also growing.Using implantable energy harvester either to recharge or ultimately replace hazardous battery is essential to provide a long-term sustainable solution.Energy harvesting techniques using piezoelectric,thermoelectric,radio frequency power transmission,biofuel,and photoelectronic(or sometimes termed as“photovoltaic”in terms of solar light harvesting,i.e.,PV)conversion,have been attempted for the implantable,but these methods are currently limited by insufficient power output,large footprint,and low efficiency.Nevertheless,the planar PV with potential of lighter weight,higher energy density,and higher efficiency,provides promising power solution for in-body medical implants.In this short review,we will discuss the potential opportunities and challenges associated with PV's for medical implants,covering materials,to devices,and to system level requirements.
基金Project supported by the Natural Science Foundation of Chongqing of China(Grant No.CSTB2023NSCQ-LZX0087)the National Natural Science Foundation of China(Grant Nos.62074021 and 12174380)。
文摘Understanding the dynamics of photoexcited carriers is essential for advancing photoelectronic device design.Photon absorption generates electron–hole pairs,and subsequent scatterings can induce ultrafast thermalization within a picosecond,forming a quasi-equilibrium distribution with overheated electrons.The high-energy tail of this distribution enables carriers to overcome energy barriers,thereby enhancing quantum efficiency—a phenomenon known as photothermionic emission(PTE).Despite its importance,the onset and mechanisms of PTE remain under debate.Using real-time timedependent density functional theory(rt-TDDFT),we investigate ultrafast carrier thermalization in two-dimensional(2D)materials graphene and PtTe2,and the results reveal distinct differences.In graphene,both electrons and holes thermalize into Fermi–Dirac distributions with good agreement to experiment,while PtTe2exhibits anomalous high-energy tails for both electrons and holes,deviating significantly from Fermi–Dirac behavior.We attribute this anomaly to differences in orbital coupling between the two materials,from which we derive design principles for identifying optimal PTE candidates and,ultimately,improving photodetector performance.
基金supported by the National Science Foundation (Grant No.CHE-2403841)。
文摘We report a study on the electronic structure and chemical bonding of the PB and AsB diatomic molecules using high-resolution photoelectron imaging of cryogenically-cooled PB^(−)and AsB^(−)anions.The electron affinities of PB and AsB are measured to be 2.751(1)and 2.600(1)eV,respectively.The ground states of the PB^(−)and AsB−anions are determined to be ^(2)Σ^(+) with a σ^(1)π^(4) valence electron configuration.The ground states of neutral PB and AsB are found to be ^(3)Π_(2) with a σ^(1)π^(3) electron configuration.The spin-orbit excited states(^(3)Π_(1) and ^(3)Π_(0)),as well as two low-lying singlet excited states(^(1)Σ^(+)and ^(1)Π),are observed.Unusual spectroscopic characteristics are observed in the ^(3)Π_(2) ground state of AsB,probably due to state mixing with a higher-lying ^(1)Δ_(2) state.The current work provides extensive electronic and spectroscopic information for the PB and AsB molecules.
基金supported by the Vinnova(project number 2020-03778)supported by the Swedish Research Council(Vetenskapsradet,project number 2021-04157).
文摘Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ray Photoelectron emission spectroscopy(HAXPES)and microscopy(HAXPEEM)as well as microscopic X-ray absorption spectroscopy(μ-XAS)techniques.The results reveal the inhomogeneity in the oxide films on the micron-sized Cr_(2)N-and VN-type particles,while the inhomogeneity on the martensite matrix phase exists due to localised formation of nano-sized tempering nitride particles at 600℃.The oxide film formed on Cr_(2)N-type particles is rich in Cr_(2)O_(3) compared with that on the martensite matrix and VN-type particles.With the increase of tempering temperature,Cr_(2)O_(3) formation is faster for the oxidation of Cr in the martensite matrix than the oxidation of Cr nitride-rich particles.
基金Projects(82171030,81870678)supported by the National Natural Science Foundation of China。
文摘Magnesium alloys as medical implant materials necessitate a lower and adjustable corrosion rate for clinical applications.The microstructure and corrosion behavior of AZ31Mn-xEr(x=0.1,0.5,1.2)alloys were systematically investigated using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray photoelectron spectroscopy(XPS),combined with Tafel polarization and electrochemical impedance spectroscopy(EIS)analyses.The findings showed that the alloying element Er refined the grain structure during solidification by increasing the nucleation rate and forming a secondary phase of Al_(3)Er with Al.The Er and Mg in the matrix co-oxidize to form a dense MgO/Er_(2)O_(3)composite oxide,preventing the formation of loose magnesium hydroxide/basic magnesium carbonate.The trace alloying element Mn interacts with impurities Fe in the magnesium matrix to form an AlFeMn second phase,reducing micro-galvanic corrosion driving force.Electrochemical testing in a 3.5%NaCl solution demonstrated a marked reduction in corrosion rate from 10.46 mm/a(AZ 31 Mn alloy)to 0.44 mm/a(AZ31Mn-1.2Er alloy).This research offers a reference for searching for corrosion-resistant magnesium alloy and degradable medical magnesium alloy materials.
基金supported by Key Laboratory of Research on Hydraulic and Hydro-Power Equipment Surface Engineering Technology of Zhejiang Province(20240304).
文摘The corrosion behaviors of an as-cast FeCoNiAl_(0.75)Cr_(1.25)high-entropy alloy(HEA)in acidic Na_(2)SO_(4)solution with different pH values were investigated.The results indicate that the as-cast FeCoNiAl_(0.75)Cr_(1.25)HEA is mainly composed of face-centered cubic phase,body-centered cubic(BCC1)phase(Co–Cr–Fe)and ordered BCC(B2)phase(Ni–Al),in which BCC1 phase and B2 phase have a eutectic microstructure.Moreover,the corrosion of B2 phase occurs preferentially in a 0.05 mol/L SO_(4)^(2−)acidic solution.The electrochemical measurement results show that the corrosion resistance of the investigated HEA significantly changes as the solution pH increases from 2 to 2.5.This indicates that there is a critical pH in the range of 2–2.5 that affects the corrosion of HEA.In addition,the results of X-ray photoelectron spectroscopy prove that the surface film of FeCoNiAl_(0.75)Cr_(1.25)in SO_(4)^(2−)solution is formed with Al_(2)O_(3)and Cr_(2)O_(3)as the main components,and The content of Al2O3 and Cr_(2)O_(3)increases with increasing solution pH.
基金Project supported by National Research and Innovation Agency of the Republic of Indonesia(Badan Riset dan Inovasi Nasional-BRIN)through the Grant of Rumah Program Organisasi Riset Nanoteknologi dan Material(RP-ORNM)No.20/Ⅲ.10/HK/2024。
文摘In the present work,the effects of neodymium(Nd)on micro structure,mechanical performance,and corrosion behavior of powder metallurgy Mg-2Si-xNd(x=0.05 wt%,0.15 wt%,and 0.20 wt%)alloys were investigated.Microstructures were examined by optical and scanning electron microscopes combined with an energy-dispersive spectrometer.Hardness and compressive tests were used to study the mechanical properties of alloys.Potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),Mott-Schottky analysis,and the hydrogen evolution test were applied to characterize the corrosion behavior of alloys in Hanks'solution.The microstructure of Mg-2Si-xNd alloys mainly consists ofα-Mg matrix,Mg2Si,and MgNd phases.The increase in Nd content tends to decrease the aspect ratio ofα-Mg grains,which leads to the enhancement of the ultimate-compressive strengths and hardness of the alloys.Potentiodynamic polarization shows that increasing Nd content leads to a lower corrosion current density in the Mg-2Si-xNd alloys.The EIS results confirm that a higher addition of Nd suppresses the dissolution kinetics of the alloys due to the increasing charge transfer resistance.Mott-Schottky analysis reveals the formation of an n-type semiconductive passive film on the alloy surfaces,where the interstitial and oxygen vacancies predominate over the metal vacancies.The X-ray photoelectron spectroscopy(XPS)reveals that a mixture of Mg(OH)_(2),MgO,MgCO_(3),and Nd_(2)O_(3)has formed as the corrosion products on the Mg-2Si-xNd alloy surfaces after a longer immersion time in Hanks'solution.
基金funded by the Air Force Office of Scientific Research (AFOSR) under Grant (No.FA955023-1-0545)。
文摘High-resolution photoelectron spectra of cryogenically cooled TiO_(2)CH_(3)OH^(−)anions obtained with slow electron velocity-map imaging are reported and used to explore the reactions of TiO_(2)^(−/0)with methanol.The highly structured spectra were compared with results from DFT calculations to determine the dominant structure to be cis-CH_(3)OTi(O)OH^(−),a dissociative adduct in which CH3OH is split by TiO_(2)^(−).The experiment yields an electron affinity of 1.2152(7)eV for TiO_(2)CH^(3)OH as well as several vibrational frequencies for the neutral species.Comparison to Franck−Condon(FC)simulations shows that while most experimental features appear in the simulations,several are not and are assigned to FC-forbidden transitions involving non-totally symmetric vibrational modes.The FC-allowed and forbidden transi-tions also exhibit different photoelectron angular distributions.The FC-forbidden transitions are attributed to Herzberg−Teller(HT)coupling with the A^(2)A″excited state of the anion.The results are compared to previous cryogenic slow electron velocity-map imaging(cryo-SE-Ⅵ)studies of bare TiO_(2)^(−)and the water-split adduct TiO_(3)H_(2)^(−).
基金supported by the National Natural Science Foundation of China(Nos.92461313,12074387,and 92161114)the Innovation Capability Support Program of Shaanxi Province(No.2023-CX-TD-49).
文摘The structure and electronic properties of Co_(2)Ge_(10)^(-)anion and its neutral counterpart were investigated by anion photoelectron spectroscopy and theoretical calculations.The experimental vertical detachment energy of Co_(2)Ge_(10)^(-)was measured to be 2.86±0.08 eV.The lowest-energy isomer of Co_(2)Ge_(10)^(-)is in a doublet state and has a cage-like structure with Cs symmetry,which can be constructed by a tetragonal bipyramid on top of a pentagonal bipyramid and these two bipyramid structures share a common Co atom.The most stable structure of neutral Co_(2)Ge_(10)resembles its anionic counterpart and it is in a triplet state.The natural population analysis showed that the inner Co atom of both the anionic and neutral Co_(2)Ge_(10)acquires negative charge from the neighboring Ge atoms.The outer Co atom has a larger spin moment than the inner Co atom,indicating that the magnetic moments of Co_(2)Ge_(10)^(-/0)are mainly contributed by the outer Co atom.Analyses of the density of states and molecular orbitals indicated that there are a few highly delocalized molecular orbitals in Co_(2)Ge_(10)^(-),which are mainly contributed by Ge 4s atomic orbitals.
基金was supported by the U.S.Department of Energy(DOE),Office of Science,Office of Basic Energy Sciences,Division of Chemical Sciences,Geosciences,and Biosciences,Condensed Phase and Interfacial Molecular Science program,FWP 16248.
文摘MgATP is a stable complex formed by the chelation of Mg^(2+)with deprotonated adenosine-5'-triphosphate(ATP).In the cellular environment,MgATP plays a critical role in ATP hydrolysis,releasing substantial energy to support essential biological functions.To understand the structure and stabilization mechanism of MgATP,we conducted a joint negative ion photoelectron spectroscopic and computational study of the[ATP^(4-)·Mg^(2+)]^(2-)complex dianion,using[ATP^(4-)·2H^(+)]^(2-)as a reference.The experimentally determined adiabatic and vertical detachment energies(ADE and VDE)of[ATP^(4-)·Mg^(2+)]^(2-)at 20 K are 3.51±0.05 eV and 3.82±0.05 eV,respectively.The major spectral features of[ATP^(4-)·Mg^(2+)]^(2-)are attributed to two theoretically identified isomers with unfolded geometries,which are stabilized primarily by electrostatic interactions between Mg^(2+)and the triphosphate and ribose groups,with four deprotonated oxygens forming a pseudo-tetrahedral coordination.In contrast,[ATP^(4-)·2H^(+)]^(2-)exhibits a fundamentally different stabilization mechanism.Although most of the fifteen identified[ATP^(4-)·2H^(+)]^(2-)isomers also adopt unfolded geometries,they are primarily stabilized by intramolecular hydrogen bonds within the triphosphate group and between triphosphate and ribose groups.The interaction between ATP^(4-)and two protons is found to be much weaker than that with Mg^(2+),and[ATP^(4-)·2H^(+)]^(2-)exhibits substantial structural flexibility compared to[ATP^(4-)·Mg^(2+)]^(2-)due to the conformational constraint of the triphosphate chain by Mg^(2+).Thirteen[ATP^(4-)·2H^(+)]^(2-)isomers with unfolded geometries likely account for the major high-EBE(electron-binding-energy)spectral features.Notably,for the first time,a low EBE and temperature-dependent spectral feature is observed and attributed to two folded isomers of[ATP^(4-)·2H^(+)]^(2-),which exist at 20 K but disappear at room temperature.This study provides valuable molecular-level insights into cellular MgATP that resides within the hydrophobic pockets of proteins.
基金supported by the National Natural Science Foundation of China(No.22273065)Shandong Energy institute(SEI U202312)"Strategic Priority Research Program"of the Chinese Academy of Sciences(No.XDA02020000).
文摘The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(2)(M=Ti,Zr,and Hf)compounds are formed in bent insertion structures.The observed ground-state adiabatic detachment energy(ADE)is measured to be 1.597±0.003,1.651±0.003,and 2.119±0.003 eV for TiO_(2)^(-),ZrO_(2)^(-),and HfO_(2)^(-),respectively.The vibrational frequencies of the anionic and neutral MO_(2)are also determined from the experimental spectra.The results of theoretical calculations show that the electronic configurations of MO_(2)^(-)are^(2)A_(1)with C_(2v)point group.Bond order analysis indicates that the two M-O bonds are all multiple characters.
基金funded by National Key Research and Development Program of China(No.2021YFB3401100)Evaluation Project of Guangdong Provincial Key Laboratory(No.2023B1212060043)+1 种基金Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001)GDAS'Project of Science and Technology Development(Nos.2023GDASQNRC-0205 and 2024GDASZH-2024010102).
文摘The corrosion behavior of CoCrCu_(0.1)FeMoNi high entropy alloy(HEA)in 0.5 mol/L NaOH solution was investigated using X-ray photoelectron spectroscopy,X-ray diffraction,scanning electron microscopy,potentiodynamic polarization measurement,and electrochemical impedance spectroscopy.The results showed that the microstructure of this HEA displayed a dendritic morphology along with inter-dendritic regions.At the applied potential of–0.3,0,and 0.1 V vs.saturated calomel electrode(SCE),no significant damage to the surface of the alloy was observed.At the applied potentials of 0.15 and 0.2 V vs.SCE,selective detachment and tearing of the microstructure on the alloy surface were observed,attributed to micro-galvanic corrosion.HEA demonstrates typical spontaneous passivation behavior and exhibits capacitance at all five applied potentials.The energy dispersive spectroscopy results indicate significant elemental segregation within HEA,with a decrease in the content of Cr_(2)O_(3)in the passive film as the applied potential increases.Consequently,the protective efficacy of the passive film over the substrate in 0.5 mol/L NaOH solution was compromised.
基金supported by JSPS KAKENHI Grant Number 22K12903.
文摘Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneity due to the degradation of Mg on its corrosion behavior.The immersion experiments using pure Mg plates,which were placed vertically in a culture medium(Dulbecco’s Modified Eagle’s Medium(DEME)+10%fetal bovine serum(FBS))for 1,5,and 10 days,were conducted.Surface analyses for the corrosion product layers and the measurements of the pH values and concentrations of eluted ions in the immersion medium around the upper and lower areas of the Mg plate were performed.The significant effect of the macroscopic environmental heterogeneity derived from Mg degradation on the corrosion behavior was demonstrated by in vitro tests.Additionally,the in vivo tests were carried out by implanting the pure Mg plates in the femur of rabbits.The in vivo results exhibited macroscopically heterogeneous Mg degradation,with areas of more severe corrosion compared to the in vitro test;it is especially noticeable during the early stage of degradation,even though the average corrosion rate was lower.
基金Project supported by Li Ka Shing Foundation STUGTIIT Joint Research(Grant No.2024LKSFG02)the STU Scientific Research Foundation for Talents(Grant Nos.NTF22026,NTF23011,NTF23014,and NTF23036T)+1 种基金the National Basic Research Program of China(Grant No.2019YFA0307700)the National Natural Science Foundation of China(Grant Nos.12074239 and 12274300)。
文摘We have performed a comparative study of the photoelectron spectra adopting different initial states(2s or 2_(p0))of hydrogen atoms in a near-infrared laser pulse by using the full three-dimensional time-dependent Schr?dinger equation.It is demonstrated that the atomic photoelectron spectra oscillate out of step as a function of electron kinetic energies for different initial states(2s or 2_(p0)),which is well reproduced by the simulations based on strong field approximation,and the above distinct feature is ascribed to the different interferences from the partial electron wave packets detached by positive and negative electric fields for different initial states of 2s and 2_(p0).
基金Project supported by the National Natural Science Foundation of China(Grant No.61874108)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2024-04)the Gansu Provincial Scientific and Technologic Planning Program(Grant No.22ZD6GE016).
文摘In order to investigate the effect of different doping types on the band alignment of heterojunctions,we prepared PtSe_(2)/n-GaN,PtSe_(2)/p-GaN,and PtSe_(2)/u-GaN heterojunctions by wet transfer technique.The valence band offsets(VBO)of the three heterojunctions were measured by x-ray photoelectron spectroscopy(XPS),while the PtSe_(2)/n-GaN is 3.70±0.15 eV,PtSe_(2)/p-GaN is 0.264±0.15 eV,and PtSe_(2)/u-GaN is 3.02±0.15 eV.The conduction band offset(CBO)of the three heterojunctions was calculated from the material bandgap and VBO,while the PtSe_(2)/n-GaN is 0.61±0.15 eV,PtSe_(2)/p-GaN is 2.83±0.15 eV,and PtSe_(2)/u-GaN is 0.07±0.15 eV.This signifies that both PtSe_(2)/u-GaN and PtSe_(2)/p-GaN exhibit type-Ⅰband alignment,but the PtSe_(2)/n-GaN heterojunction has type-Ⅲband alignment.This signifies that the band engineering of PtSe_(2)/GaN heterojunction can be achieved by manipulating the concentration and type of doping,which is significantly relevant for the advancement of related devices through the realization of band alignment and the modulation of the material properties of the PtSe_(2)/GaN heterojunction.
