Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to cr...Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to creating stable physical colors on the surface of lithium niobate crystals by combining gold ion implantation with laser direct writing technologies.The interaction between the laser,the implanted gold nanoparticles,and the crystal lattice induces permanent,localized modifications on the crystal surface.By fine-tuning the laser direct writing parameters,we reshaped the gold nanoparticles into spheres of varying sizes on the crystal surface,resulting in the display of red,green,blue,and pale-yellow colors.We investigated the influence of the implanted Au nanoparticles-particularly their localized surface plasmon resonances-on the modifications of the lithium niobate crystal lattice during the laser writing process using confocal Raman spectroscopy and high-resolution transmission electron microscopy.Our findings reveal that the embedded Au nanoparticles play a pivotal role in altering the conventional light-matter interaction between the crystal lattice and the laser,thereby facilitating the generation of surface colors.This work opens new avenues for the development of vibrant surface colors on transparent dielectric crystals.展开更多
In the post-lithium-ion battery era,potassium-ion batteries(PIBs)show great potential due to their high energy density and economic competitiveness from abundant potassium resources.In comparison with traditional orga...In the post-lithium-ion battery era,potassium-ion batteries(PIBs)show great potential due to their high energy density and economic competitiveness from abundant potassium resources.In comparison with traditional organic electrolytes,aqueous electrolytes bring lower costs,higher safety,and more environmentally friendly preparation processes for PIBs.Against this background,aqueous PIBs(APIBs)have gradually become a research hotspot in the past few years.Cathodes,a critical component of APIBs,directly affect energy density,safety,and stability.Herein,this review systematically summarizes the research progress of typical APIB cathode materials,some breakthrough investigations of which are highlighted.Meanwhile,material synthesis methods,electrolyte design strategies,electrochemical performance optimization pathways,and electrochemical reaction mechanisms are introduced briefly.Finally,the current challenges and corresponding improvement strategies are proposed to provide a reference for further development.展开更多
We show the structural and optical properties of non-polar a-plane GaN epitaxial films modified by Si ion implantation.Upon gradually raising Si fluences from 5×10^(13)cm^(-2)to 5×10^(15)cm^(-2),the n-type d...We show the structural and optical properties of non-polar a-plane GaN epitaxial films modified by Si ion implantation.Upon gradually raising Si fluences from 5×10^(13)cm^(-2)to 5×10^(15)cm^(-2),the n-type dopant concentration gradually increases from 4.6×10^(18)cm^(-2)to 4.5×10^(20)cm^(-2),while the generated vacancy density accordingly raises from 3.7×10^(13)cm^(-2)to 3.8×10^(15)cm^(-2).Moreover,despite that the implantation enhances structural disorder,the epitaxial structure of the implanted region is still well preserved which is confirmed by Rutherford backscattering channeling spectrometry measurements.The monotonical uniaxial lattice expansion along the a direction(out-of-plane direction)is observed as a function of fluences till 1×10^(15)cm^(-2),which ceases at the overdose of 5×10^(15)cm^(-2)due to the partial amorphization in the surface region.Upon raising irradiation dose,a yellow emission in the as-grown sample is gradually quenched,probably due to the irradiation-induced generation of non-radiative recombination centers.展开更多
The immobilization of biomaterials on a carrier is the first step for many different applications in life science and medicine. The usage of surface-near electrostatic forces is one possible approach to guide the char...The immobilization of biomaterials on a carrier is the first step for many different applications in life science and medicine. The usage of surface-near electrostatic forces is one possible approach to guide the charged biomaterials to a specific location on the carrier. In this study, we investigate the effect of intrinsic defects on the surface potential of silicon carriers in the dark and under illumination by means of Kelvin probe force microscopy. The intrinsic defects were introduced into the carrier by local, stripe-patterned ion implantation of silicon ions with a fluence of 3 × 10<sup>13</sup> Si ions/cm<sup>2</sup> and 3 × 10<sup>15</sup> Si ions/cm<sup>2</sup> into a p-type silicon wafer with a dopant concentration of 9 × 10<sup>15</sup> B/cm<sup>3</sup>. The patterned implantation allows a direct comparison between the surface potential of the silicon host against the surface potential of implanted stripes. The depth of the implanted silicon ions in the target and the concentration of displaced silicon atoms was simulated using the Stopping and Range of Ions in Matter (SRIM) software. The low fluence implantation shows a negligible effect on the measured Kelvin bias in the dark, whereas the large fluence implantation leads to an increased Kelvin bias, i.e. to a smaller surface work function according to the contact potential difference model. Illumination causes a reduced surface band bending and surface potential in the non-implanted regions. The change of the Kelvin bias in the implanted regions under illumination provides insight into the mobility and lifetime of photo-generated electron-hole pairs. Finally, the effect of annealing on the intrinsic defect density is discussed and compared with atomic force microscopy measurements on the 2<sup>nd</sup> harmonic. In addition, by using the Baumgart, Helm, Schmidt interpretation of the measured Kelvin bias, the dopant concentration after implantation is estimated.展开更多
The resistance of wear protective coatings against oxidation is crucial for their use at high temperatures.Here,three nanocomposite AlCr(Si)N coatings with a fixed Al/Cr atomic ratio of 70/30 and a varying Si-content ...The resistance of wear protective coatings against oxidation is crucial for their use at high temperatures.Here,three nanocomposite AlCr(Si)N coatings with a fixed Al/Cr atomic ratio of 70/30 and a varying Si-content of 0 at.%,2.5 at.% and 5 at.% were analyzed by differential scanning calorimetry,thermogravimetric analysis and X-ray in order to understand the oxidation behavior depending on their Si-content.Additionally,a partially oxidized AlCrSiN coating with 5 at.%Si on a sapphire substrate was studied across the coating thickness by depth-resolved cross-sectional X-ray nanodiffraction and scanning trans-mission electron microscopy to investigate the elemental composition,morphology,phases and residual stress evolution of the oxide scale and the non-oxidized coating underneath.The results reveal enhanced oxidation properties of the AlCr(Si)N coatings with increasing Si-content,as demonstrated by a retarded onset of oxidation to higher temperatures from 1100℃ for AlCrN to 1260℃ for the Si-containing coatings and a simultaneous deceleration of the oxidation process.After annealing of the AlCrSiN sample with5 at.%Si at an extraordinary high temperature of 1400℃ for 60 min in ambient air,three zones developed throughout the coating strongly differing in their composition and structure:(i)a dense oxide layer comprising an Al-rich and a Cr-rich zone formed at the very top,followed by(ii)a fine-grained transition zone with incomplete oxidation and(iii)a non-oxidized zone with a porous structure.The varying elemental composition of these zones is furthermore accompanied by micro-structural variations and a complex residual stress development revealed by cross-sectional X-ray nanodiffraction.The results provide a deeper understanding of the oxidation behavior of AlCr(Si)N coatings depending on their Si-content and the associated elemental,microstructural and residual stress evolution during high-temperature oxidation.展开更多
An induction levitation melting （ILM） refining process is performed to remove most microsized inclusions in ultra-low carbon steel （UCS）. Nanosized, spheroid shaped sulfide precipitates remain dispersed in the UCS...An induction levitation melting （ILM） refining process is performed to remove most microsized inclusions in ultra-low carbon steel （UCS）. Nanosized, spheroid shaped sulfide precipitates remain dispersed in the UCS. During the ILM process, the UCS is molten and is rotated under an upward magnetic field. With the addition of Ti additives, the spinning molten steel under the upward magnetic field ejects particles because of resultant centrifugal, floating, and magnetic forces. Magnetic force plays a key role in removing sub-micrometer-sized particles, composed of porous aluminum titanate enwrapping alumina nuclei. Consequently, sulfide precipitates with sizes less than 50 nan remain dispersed in the steel matrix. These findings open a path to the fabrication of clean steel or steel bearing only a nanosized strengthen- ing phase.展开更多
In this study, aluminum-doped zinc oxide(AZO) thin films were deposited onto a low-temperature polyethylene terephthalate(PET) substrate using DC magnetron sputtering. Deposition parameters included power range of 100...In this study, aluminum-doped zinc oxide(AZO) thin films were deposited onto a low-temperature polyethylene terephthalate(PET) substrate using DC magnetron sputtering. Deposition parameters included power range of 100-300 W, a working pressure of 15 mTorr, and a substrate temperature of 50 ℃. Post-deposition, flash lamp annealing(FLA) was employed as a rapid thermal processing method with a pulse duration of 1.7 ms and energy density of 7 J·cm-2, aimed at enhancing the film's quality while preserving the temperature-sensitive PET substrate. FLA offers advantages over conventional annealing,including shorter processing times and improved material properties. The structural, optical, and electrical characteristics of the AZO films were assessed using X-ray diffraction, field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, ultraviolet-visible spectroscopy, and Hall effect measurements. The results demonstrated that properties of AZO films varied with deposition and annealing conditions. Films deposited at 200 W and subjected to FLA exhibited superior crystallinity, with average visible light transmittance exceeding 80% and resistivity as low as 0.38 Ω·cm representing 95%improvement in transmittance. Electrical analysis revealed that carrier concentration, mobility, and resistivity were influenced by both sputtering and annealing parameters. These findings underscore the effectiveness of FLA in optimizing AZO thin film properties, highlighting potential in optoelectronics applications.展开更多
In the modern technological landscape,magnetic field sensors play a crucial role and are indispensable across a range of high-tech applications[1].In conjunction with magnets,magnetic field sensors can accurately dete...In the modern technological landscape,magnetic field sensors play a crucial role and are indispensable across a range of high-tech applications[1].In conjunction with magnets,magnetic field sensors can accurately detect any form of relative movement of objects without physical contact.For instance,in the precise control of robotic arms or machine tools,a permanent magnet is used as a reference.The magnetic sensor detects the relative movement of magnet by sensing changes in the magnetic field strength.These changes are converted into electrical signals,which are fed back to the control system,enabling accurate positioning and control of the device.This advanced detection technology not only greatly enhances measurement precision but also significantly extends the lifespan of equipment.Among various types of magnetic field sensors,magnetoresistive(MR)sensors stand out for their exceptional performance[1].The high sensitivity allows them to detect minimal changes of magnetic fields in high-precision measurements.Today,MR sensors are widely used across numerous fields,including automobile industries,information processing and storage,navigation systems,biomedical applications,etc[1,2].With their outstanding performance and wide-ranging applications,MR sensors are at the forefront of sensor technology.展开更多
The application of polymers to replace oleylamine(OLA)and oleic acid(OA)as ligands for perovskite nanocrystals is an effective strategy to improve their stability and durability especially for the solution-based proce...The application of polymers to replace oleylamine(OLA)and oleic acid(OA)as ligands for perovskite nanocrystals is an effective strategy to improve their stability and durability especially for the solution-based processing.Herein,we report a mechanosynthesis of lead bromide perovskite nanoparticles(NPs)stabilized by partially hydrolyzed poly(methyl methacrylate)(h-PMMA)and highmolecular-weight highly-branched poly(ethylenimine)(PEI-25K).The as-synthesized NP solutions exhibited green emission centered at 516 nm,possessing a narrow full-width at half-maximum of 17 nm and as high photoluminescence quantum yield(PL QY)as 85%,while showing excellent durability and resistance to polar solvents,e.g.,methanol.The colloids of polymer-stabilized NPs were directly processable toform stable and strongly-emitting thin films and solids,making them attractive as gain media.Furthermore,the roles of h-PMMA and PEI-25K in the grinding process were studied in depth.The h-PMMA can form micelles in the grinding solvent of dichloromethane to act as size-regulating templates for the growth of NPs.The PEI-25K with large amounts of amino groups induced significant enrichment of PbBr_(2)in the reaction mixture,which in turn caused the formation of CsPb_(2)Br_(5)-mPbBr_(2)and CsPbBr_(3)-Cs_(4)PbBr_(6)-nCsBr NPs.The presence of CsPbBr_(3)-Cs_(4)PbBr_(6)-nCsBr NPs was responsible for the high PL QY,as the Cs_(4)PbBr_(6)phase with a wide energy bandgap can passivate the surface defects of the CsPbBr_(3)phase.This work describes a direct and facile mechanosynthesis of polymer-coordinated perovskite NPs and promotes in-depth understanding of the formation and phase conversion for perovskite NPs in the grinding process.展开更多
Plasmonics offers a promising framework for next-generation photonic applications,including optical tweezers,ultrafast lasing,and quantum communication.Integrating plasmonics into photonics enables efficient interface...Plasmonics offers a promising framework for next-generation photonic applications,including optical tweezers,ultrafast lasing,and quantum communication.Integrating plasmonics into photonics enables efficient interface coupling between heterogeneous systems,resulting in enhanced performance and diverse functionality.This review presents various unique encapsulation methods for developing plasmonics-embedded hybrid nanocomposite systems.Recent progress in the manipulation mechanisms of encapsulated plasmons is systematically summarized,offering an active modulation platform for optimizing optical performance.Considering the opportunities and challenges,the advancement of tunable encapsulated plasmons exhibits promising prospects,as demonstrated by a section discussing recent significant progress in photonic applications.展开更多
In the present work,the high uniform 6-inch single-crystalline AlN template is successfully achieved by high temperature annealing technique,which opens up the path towards industrial application in power device.Moreo...In the present work,the high uniform 6-inch single-crystalline AlN template is successfully achieved by high temperature annealing technique,which opens up the path towards industrial application in power device.Moreover,the outstanding crystalline-quality is confirmed by Rutherford backscattering spectrometry(RBS).In accompanied with the results from X-ray diffraction,the RBS results along both[0001]and[1213]reveal that the in-plane lattice is effectively reordered by high temperature annealing.In addition,the constantΦ_(epi)angle between[0001]and[1213]at different depths of 31.54°confirms the uniform compressive strain inside the AlN region.Benefitting from the excellent crystalline quality of AlN template,we can epitaxially grow the enhanced-mode high electron mobility transistor(HEMT)with a graded AlGaN buffer as thin as only~300 nm.Such an ultra-thin AlGaN buffer layer results in the wafer-bow as low as 18.1μm in 6-inch wafer scale.The fabricated HEMT devices with 16μm-L_(GD)exhibits a threshold voltage(V_(TH))of 1.1 V and a high OFF-state breakdown voltage(V_(BD))over 1400 V.Furthermore,after 200 V high-voltage OFF-state stress,the current collapse is only 13.6%.Therefore,the advantages of both 6-inch size and excellent crystallinity announces the superiority of single-crystalline AlN template in low-cost electrical power applications.展开更多
Color centers in silicon carbide(SiC)are promising candidates for quantum technologies.However,the richness of the polytype and defect configuration of SiC makes the accurate control of the types and position of defec...Color centers in silicon carbide(SiC)are promising candidates for quantum technologies.However,the richness of the polytype and defect configuration of SiC makes the accurate control of the types and position of defects in SiC still challenging.In this study,helium ion-implanted 4H-SiC was characterized by atomic force microscopy(AFM),confocal photoluminescence(PL),and confocal Raman spectroscopy at room temperature.PL signals of silicon vacancy were found and analyzed using 638-nm and 785-nm laser excitation by means of depth profiling and SWIFT mapping.Lattice defects(C-C bond)were detected by continuous laser excitation at 532 nm and 638 nm,respectively.PL/Raman depth profiling was helpful in revealing the three-dimensional distribution of produced defects.Differences in the depth profiling results and SRIM simulation results were explained by considering the depth resolution of the confocal measurement setup,helium bubbles,as well as swelling.展开更多
Contrary to the common belief that the light-induced halide ion segregation in a mixed halide alloy occurs within the illuminated area,we find that the Br ions released by light are expelled from the illuminated area,...Contrary to the common belief that the light-induced halide ion segregation in a mixed halide alloy occurs within the illuminated area,we find that the Br ions released by light are expelled from the illuminated area,which generates a macro/mesoscopic size anion ring surrounding the illuminated area,exhibiting a photoluminescence ring.This intriguing phenomenon can be explained as resulting from two counter-balancing effects:the outward diffusion of the light-induced free Br ions and the Coulombic force between the anion deficit and surplus region.Right after removing the illumination,the macro/mesoscopic scale ion displacement results in a built-in voltage of about 0.4 V between the ring and the center.Then,the displaced anions return to the illuminated area,and the restoring force leads to a damped ultra-low-frequency oscillatory ion motion,with a period of about 20-30 h and lasting over 100 h.This finding may be the first observation of an ionic plasma oscillation in solids.Our understanding and controlling the"ion segregation"demonstrate that it is possible to turn this commonly viewed"adverse phenomenon"into novel electronic applications,such as ionic patterning,self-destructive memory,and energy storage.展开更多
Plasma waves play an important role in many solid-state phenomena and devices.They also become significant in electronic device structures as the operation frequencies of these devices increase.A prominent example is ...Plasma waves play an important role in many solid-state phenomena and devices.They also become significant in electronic device structures as the operation frequencies of these devices increase.A prominent example is field-effect transistors(FETs),that witness increased attention for application as rectifying detectors and mixers of electromagnetic waves at gigahertz and terahertz frequencies,where they exhibit very good sensitivity even high above the cut-off frequency defined by the carrier transit time.Transport theory predicts that the coupling of radiation at THz frequencies into the channel of an antenna-coupled FET leads to the development of a gated plasma wave,collectively involving the charge carriers of both the two-dimensional electron gas and the gate electrode.In this paper,we present the first direct visualization of these waves.Employing graphene FETs containing a buried gate electrode,we utilize near-field THz nanoscopy at room temperature to directly probe the envelope function of the electric field amplitude on the exposed graphene sheet and the neighboring antenna regions.Mapping of the field distribution documents that wave injection is unidirectional from the source side since the oscillating electrical potentials on the gate and drain are equalized by capacitive shunting.The plasma waves,excited at 2 THz,are overdamped,and their decay time lies in the range of 25-70 fs.Despite this short decay time,the decay length is rather long,i.e.,0.3-0.5μm,because of the rather large propagation speed of the plasma waves,which is found to lie in the range of 3.5-7×10^(6)m/s,in good agreement with theory.The propagation speed depends only weakly on the gate voltage swing and is consistent with the theoretically predicted 1/4 power law.展开更多
Three-dimensional(3D)graphene networks are performance boosters for functional nanostructures in energy-related fields.Although tremendous intriguing nanostructures-decorated 3D graphene networks have been realized,on...Three-dimensional(3D)graphene networks are performance boosters for functional nanostructures in energy-related fields.Although tremendous intriguing nanostructures-decorated 3D graphene networks have been realized,on-demand decoration of nanostructures in the specified position of interest within the whole 3D graphene skeleton is still out of reach,shedding limitations on constructing more sophisticated components with programmable structures which offer enormous potential for the enhancement of performance and exploration of new functions.Here,we report the melamine-sponge(MS)-templated hydrothermal method capable of realizing reduced graphene oxide(RGO)-nanostructure composite aerogels with programmable structures and compositions.The key of this method is using the MS template to preset the structures of choice through programmable solution-processed immobilization of graphene oxide(GO)and nanostructures.Remarkably,the hydrothermal treatment simultaneously removed the MS template and reduced the GO networks without changing the preset structures.We showcased nine typical RGO-nanostructures composite aerogels to demonstrate the versatility of the MS-templated hydrothermal method.展开更多
Successful application of two-dimensional transition metal dichalcogenides in optoelectronic,catalytic,or sensing devices heavily relies on the materials’quality,that is,the thickness uniformity,presence of grain bou...Successful application of two-dimensional transition metal dichalcogenides in optoelectronic,catalytic,or sensing devices heavily relies on the materials’quality,that is,the thickness uniformity,presence of grain boundaries,and the types and concentrations of point defects.Raman spectroscopy is a powerful and nondestructive tool to probe these factors but the interpretation of the spectra,especially the separation of different contributions,is not straightforward.Comparison to simulated spectra is beneficial,but for defective systems first-principles simulations are often computationally too expensive due to the large sizes of the systems involved.Here,we present a combined first-principles and empirical potential method for simulating Raman spectra of defective materials and apply it to monolayer MoS_(2) with random distributions of Mo and S vacancies.We study to what extent the types of vacancies can be distinguished and provide insight into the origin of different evolutions of Raman spectra upon increasing defect concentration.We apply to our simulated spectra the phonon confinement model used in previous experiments to assess defect concentrations,and show that the simplest form of the model is insufficient to fully capture peak shapes,but a good match is obtained when the type of phonon confinement and the full phonon dispersion relation are accounted for.展开更多
In this study,we unveil a conceptual technology for fabricating artificial metalloenzymes(ArMs)by deeply integrating hemin into protein scaffolds via a protein refolding process,a method that transcends the convention...In this study,we unveil a conceptual technology for fabricating artificial metalloenzymes(ArMs)by deeply integrating hemin into protein scaffolds via a protein refolding process,a method that transcends the conventional scope of surface-level modifications.Our approach involves denaturing proteins,such as benzaldehyde lyase,green fluorescent protein,and Candida antarctica lipase B,to expose extensive reactive amino acid residues,which are then intricately linked with hemin using orthogonal click reactions,followed by protein refolding.This process not only retains the proteins’structural integrity but expands proteins’functionality.The most notable outcome of this methodology is the hemin@BAL variant,which demonstrated a remarkable 83.7%conversion rate in cyclopropanation reactions,far surpassing the capabilities of traditional hemin-based catalysis in water.This success highlights the significant role of protein structure in the ArMs’activity and marks a substantial leap forward in chemical modification of proteins.Our findings suggest vast potentials of protein refolding approaches for ArMs across various catalytic applications,paving the way for future advancements in synthetic biology and synthetic chemistry.展开更多
Phase-stable electromagnetic pulses in the THz frequency range offer several unique capabilities in time-resolved spectroscopy.However,the diversity of their application is limited by the covered spectral bandwidth.In...Phase-stable electromagnetic pulses in the THz frequency range offer several unique capabilities in time-resolved spectroscopy.However,the diversity of their application is limited by the covered spectral bandwidth.In particular,the upper frequency limit of photoconductive emitters-the most widespread technique in THz spectroscopy-reaches only up to 7 THz in the regular transmission mode due to absorption by infrared-active optical phonons.Here,we present ultrabroadband(extending up to 70 THz)THz emission from an Au-implanted Ge emitter that is compatible with mode-locked fibre lasers operating at wavelengths of 1.1 and 1.55μm with pulse repetition rates of 10 and 20 MHz,respectively.This result opens up the possibility for the development of compact THz photonic devices operating up to multi-THz frequencies that are compatible with Si CMOS technology.展开更多
基金supported by the National Natural Science Foundation of China (NSFC) (Grants No. 12274236, 12134009, 12074223)Shandong Provincial Natural Science Foundation (Grants No. 2022HWYQ-047, ZR2024MA041)+3 种基金Taishan Scholars Program of Shandong Province (Grants No. tsqn201909041)“Qilu Young Scholar Program” of Shandong UniversityCore Facility Sharing Platform of Shandong UniversityOpen Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems
文摘Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to creating stable physical colors on the surface of lithium niobate crystals by combining gold ion implantation with laser direct writing technologies.The interaction between the laser,the implanted gold nanoparticles,and the crystal lattice induces permanent,localized modifications on the crystal surface.By fine-tuning the laser direct writing parameters,we reshaped the gold nanoparticles into spheres of varying sizes on the crystal surface,resulting in the display of red,green,blue,and pale-yellow colors.We investigated the influence of the implanted Au nanoparticles-particularly their localized surface plasmon resonances-on the modifications of the lithium niobate crystal lattice during the laser writing process using confocal Raman spectroscopy and high-resolution transmission electron microscopy.Our findings reveal that the embedded Au nanoparticles play a pivotal role in altering the conventional light-matter interaction between the crystal lattice and the laser,thereby facilitating the generation of surface colors.This work opens new avenues for the development of vibrant surface colors on transparent dielectric crystals.
基金financially supported by the National Natural Science Foundation of China(52201259,52202286,52002094)the Education Department of Liaoning Province(JYTQN2023285)+5 种基金the Shenyang University of Technology(QNPY202209-4)the Key Laboratory of Functional Inorganic Material Chemistry(Heilongjiang University,Ministry of Education)the Science and Technology Department of Liaoning Province(2024-BSLH-172,JYTMS20231216)the Natural Science Foundation of Zhejiang Province(LY24B030006)the Science and Technology Plan Project of Wenzhou Municipality(ZG2024055)the Shenzhen Science and Technology Innovation Program(RCBS20210706092218040)。
文摘In the post-lithium-ion battery era,potassium-ion batteries(PIBs)show great potential due to their high energy density and economic competitiveness from abundant potassium resources.In comparison with traditional organic electrolytes,aqueous electrolytes bring lower costs,higher safety,and more environmentally friendly preparation processes for PIBs.Against this background,aqueous PIBs(APIBs)have gradually become a research hotspot in the past few years.Cathodes,a critical component of APIBs,directly affect energy density,safety,and stability.Herein,this review systematically summarizes the research progress of typical APIB cathode materials,some breakthrough investigations of which are highlighted.Meanwhile,material synthesis methods,electrolyte design strategies,electrochemical performance optimization pathways,and electrochemical reaction mechanisms are introduced briefly.Finally,the current challenges and corresponding improvement strategies are proposed to provide a reference for further development.
基金the Key-Area Research and Development Program of Guangdong Province,China(Grant Nos.2019B010132001,2020B010174003,and 2019B121204004)the Basic and Application Basic Research Foundation of Guangdong Province,China(Grant Nos.2020A1515110891 and 2019A1515111053)the Fund from the Ion Beam Center(IBC)at HZDR.
文摘We show the structural and optical properties of non-polar a-plane GaN epitaxial films modified by Si ion implantation.Upon gradually raising Si fluences from 5×10^(13)cm^(-2)to 5×10^(15)cm^(-2),the n-type dopant concentration gradually increases from 4.6×10^(18)cm^(-2)to 4.5×10^(20)cm^(-2),while the generated vacancy density accordingly raises from 3.7×10^(13)cm^(-2)to 3.8×10^(15)cm^(-2).Moreover,despite that the implantation enhances structural disorder,the epitaxial structure of the implanted region is still well preserved which is confirmed by Rutherford backscattering channeling spectrometry measurements.The monotonical uniaxial lattice expansion along the a direction(out-of-plane direction)is observed as a function of fluences till 1×10^(15)cm^(-2),which ceases at the overdose of 5×10^(15)cm^(-2)due to the partial amorphization in the surface region.Upon raising irradiation dose,a yellow emission in the as-grown sample is gradually quenched,probably due to the irradiation-induced generation of non-radiative recombination centers.
文摘The immobilization of biomaterials on a carrier is the first step for many different applications in life science and medicine. The usage of surface-near electrostatic forces is one possible approach to guide the charged biomaterials to a specific location on the carrier. In this study, we investigate the effect of intrinsic defects on the surface potential of silicon carriers in the dark and under illumination by means of Kelvin probe force microscopy. The intrinsic defects were introduced into the carrier by local, stripe-patterned ion implantation of silicon ions with a fluence of 3 × 10<sup>13</sup> Si ions/cm<sup>2</sup> and 3 × 10<sup>15</sup> Si ions/cm<sup>2</sup> into a p-type silicon wafer with a dopant concentration of 9 × 10<sup>15</sup> B/cm<sup>3</sup>. The patterned implantation allows a direct comparison between the surface potential of the silicon host against the surface potential of implanted stripes. The depth of the implanted silicon ions in the target and the concentration of displaced silicon atoms was simulated using the Stopping and Range of Ions in Matter (SRIM) software. The low fluence implantation shows a negligible effect on the measured Kelvin bias in the dark, whereas the large fluence implantation leads to an increased Kelvin bias, i.e. to a smaller surface work function according to the contact potential difference model. Illumination causes a reduced surface band bending and surface potential in the non-implanted regions. The change of the Kelvin bias in the implanted regions under illumination provides insight into the mobility and lifetime of photo-generated electron-hole pairs. Finally, the effect of annealing on the intrinsic defect density is discussed and compared with atomic force microscopy measurements on the 2<sup>nd</sup> harmonic. In addition, by using the Baumgart, Helm, Schmidt interpretation of the measured Kelvin bias, the dopant concentration after implantation is estimated.
基金financially supported by Christian Doppler Research Associationfinancial support by the Austrian Federal Ministry for Digital and Economic A airs and the National Foundation for Research,Technology and Development。
文摘The resistance of wear protective coatings against oxidation is crucial for their use at high temperatures.Here,three nanocomposite AlCr(Si)N coatings with a fixed Al/Cr atomic ratio of 70/30 and a varying Si-content of 0 at.%,2.5 at.% and 5 at.% were analyzed by differential scanning calorimetry,thermogravimetric analysis and X-ray in order to understand the oxidation behavior depending on their Si-content.Additionally,a partially oxidized AlCrSiN coating with 5 at.%Si on a sapphire substrate was studied across the coating thickness by depth-resolved cross-sectional X-ray nanodiffraction and scanning trans-mission electron microscopy to investigate the elemental composition,morphology,phases and residual stress evolution of the oxide scale and the non-oxidized coating underneath.The results reveal enhanced oxidation properties of the AlCr(Si)N coatings with increasing Si-content,as demonstrated by a retarded onset of oxidation to higher temperatures from 1100℃ for AlCrN to 1260℃ for the Si-containing coatings and a simultaneous deceleration of the oxidation process.After annealing of the AlCrSiN sample with5 at.%Si at an extraordinary high temperature of 1400℃ for 60 min in ambient air,three zones developed throughout the coating strongly differing in their composition and structure:(i)a dense oxide layer comprising an Al-rich and a Cr-rich zone formed at the very top,followed by(ii)a fine-grained transition zone with incomplete oxidation and(iii)a non-oxidized zone with a porous structure.The varying elemental composition of these zones is furthermore accompanied by micro-structural variations and a complex residual stress development revealed by cross-sectional X-ray nanodiffraction.The results provide a deeper understanding of the oxidation behavior of AlCr(Si)N coatings depending on their Si-content and the associated elemental,microstructural and residual stress evolution during high-temperature oxidation.
基金supported partly by the National Natural Science Foundation of China (No. 51472170)the Major State Basic Research Development Program of China (No. 2011CB932700)
文摘An induction levitation melting （ILM） refining process is performed to remove most microsized inclusions in ultra-low carbon steel （UCS）. Nanosized, spheroid shaped sulfide precipitates remain dispersed in the UCS. During the ILM process, the UCS is molten and is rotated under an upward magnetic field. With the addition of Ti additives, the spinning molten steel under the upward magnetic field ejects particles because of resultant centrifugal, floating, and magnetic forces. Magnetic force plays a key role in removing sub-micrometer-sized particles, composed of porous aluminum titanate enwrapping alumina nuclei. Consequently, sulfide precipitates with sizes less than 50 nan remain dispersed in the steel matrix. These findings open a path to the fabrication of clean steel or steel bearing only a nanosized strengthen- ing phase.
基金supported by the MOTIE (Ministry of Trade,Industry,and Energy)in Korea,under the Fostering Global Talents for Innovative Growth Program (P0017308)supervised by the Korea Institute for Advancement of Technology (KIAT)+1 种基金supported by the MSIT (Ministry of Science and ICT),Korea,under the ITRC (Information Technology Research Center)support program (IITP-2024-2020-0-01655)supervised by the IITP (Institute of Information and Communications Technology Planning and Evaluation).
文摘In this study, aluminum-doped zinc oxide(AZO) thin films were deposited onto a low-temperature polyethylene terephthalate(PET) substrate using DC magnetron sputtering. Deposition parameters included power range of 100-300 W, a working pressure of 15 mTorr, and a substrate temperature of 50 ℃. Post-deposition, flash lamp annealing(FLA) was employed as a rapid thermal processing method with a pulse duration of 1.7 ms and energy density of 7 J·cm-2, aimed at enhancing the film's quality while preserving the temperature-sensitive PET substrate. FLA offers advantages over conventional annealing,including shorter processing times and improved material properties. The structural, optical, and electrical characteristics of the AZO films were assessed using X-ray diffraction, field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, ultraviolet-visible spectroscopy, and Hall effect measurements. The results demonstrated that properties of AZO films varied with deposition and annealing conditions. Films deposited at 200 W and subjected to FLA exhibited superior crystallinity, with average visible light transmittance exceeding 80% and resistivity as low as 0.38 Ω·cm representing 95%improvement in transmittance. Electrical analysis revealed that carrier concentration, mobility, and resistivity were influenced by both sputtering and annealing parameters. These findings underscore the effectiveness of FLA in optimizing AZO thin film properties, highlighting potential in optoelectronics applications.
文摘In the modern technological landscape,magnetic field sensors play a crucial role and are indispensable across a range of high-tech applications[1].In conjunction with magnets,magnetic field sensors can accurately detect any form of relative movement of objects without physical contact.For instance,in the precise control of robotic arms or machine tools,a permanent magnet is used as a reference.The magnetic sensor detects the relative movement of magnet by sensing changes in the magnetic field strength.These changes are converted into electrical signals,which are fed back to the control system,enabling accurate positioning and control of the device.This advanced detection technology not only greatly enhances measurement precision but also significantly extends the lifespan of equipment.Among various types of magnetic field sensors,magnetoresistive(MR)sensors stand out for their exceptional performance[1].The high sensitivity allows them to detect minimal changes of magnetic fields in high-precision measurements.Today,MR sensors are widely used across numerous fields,including automobile industries,information processing and storage,navigation systems,biomedical applications,etc[1,2].With their outstanding performance and wide-ranging applications,MR sensors are at the forefront of sensor technology.
基金G.J.acknow ledges the China Scholarship Council(No.201706740088).This work was partly supported by the bilateral IB-BMBF-TOBITAK Project ColMiBack(01DL20002)and DFG project EY 16/14-3.O.E.acknowledges TOBITAK for the financial support through BIDEB-2211 program.H.V.D.gratefully acknowledges support from TUBA.The use of the HZDR Ion Beam Center TEM facilities and the funding of TEM Talos by the German Federal Ministry of Education of Research(BMBF),Grant No.03SF0451,in the framework o f HEMCP are acknowledged.M.G.acknowledges the Swiss National Science Foundation(SNF)and the German Research Foundation(DFG EY 16/18-2)for financial support.W.W.received supports from Jiangsu Overseas Visiting Scholar Program for University Prom inent Young&Middle-aged Teachers and Presidents.X.F.acknowledges the China Scholarship Council(No.201606340161).J.W.received supports from the National Natural Science Foundation of China(No.21701143).We are very grateful to Prof.A lexander Eychmuller,Dr.Vladim ir Lesnyak and Dr.Alexey Shavel for the valuable discussions.We are grateful to Susanne Goldberg for TEM imaging,Franziska Eichler for the instruction to the PL decay measurements.We appreciate Linlin Wang and Dr.Juliane Simmchen for their help with DLS measurements.We thank Dr.Andre Wolf for his corrections to the draft.
文摘The application of polymers to replace oleylamine(OLA)and oleic acid(OA)as ligands for perovskite nanocrystals is an effective strategy to improve their stability and durability especially for the solution-based processing.Herein,we report a mechanosynthesis of lead bromide perovskite nanoparticles(NPs)stabilized by partially hydrolyzed poly(methyl methacrylate)(h-PMMA)and highmolecular-weight highly-branched poly(ethylenimine)(PEI-25K).The as-synthesized NP solutions exhibited green emission centered at 516 nm,possessing a narrow full-width at half-maximum of 17 nm and as high photoluminescence quantum yield(PL QY)as 85%,while showing excellent durability and resistance to polar solvents,e.g.,methanol.The colloids of polymer-stabilized NPs were directly processable toform stable and strongly-emitting thin films and solids,making them attractive as gain media.Furthermore,the roles of h-PMMA and PEI-25K in the grinding process were studied in depth.The h-PMMA can form micelles in the grinding solvent of dichloromethane to act as size-regulating templates for the growth of NPs.The PEI-25K with large amounts of amino groups induced significant enrichment of PbBr_(2)in the reaction mixture,which in turn caused the formation of CsPb_(2)Br_(5)-mPbBr_(2)and CsPbBr_(3)-Cs_(4)PbBr_(6)-nCsBr NPs.The presence of CsPbBr_(3)-Cs_(4)PbBr_(6)-nCsBr NPs was responsible for the high PL QY,as the Cs_(4)PbBr_(6)phase with a wide energy bandgap can passivate the surface defects of the CsPbBr_(3)phase.This work describes a direct and facile mechanosynthesis of polymer-coordinated perovskite NPs and promotes in-depth understanding of the formation and phase conversion for perovskite NPs in the grinding process.
基金supported by the National Natural Science Foundation of China(12235009)Taishan Scholars Program of Shandong Province(tspd20210303).
文摘Plasmonics offers a promising framework for next-generation photonic applications,including optical tweezers,ultrafast lasing,and quantum communication.Integrating plasmonics into photonics enables efficient interface coupling between heterogeneous systems,resulting in enhanced performance and diverse functionality.This review presents various unique encapsulation methods for developing plasmonics-embedded hybrid nanocomposite systems.Recent progress in the manipulation mechanisms of encapsulated plasmons is systematically summarized,offering an active modulation platform for optimizing optical performance.Considering the opportunities and challenges,the advancement of tunable encapsulated plasmons exhibits promising prospects,as demonstrated by a section discussing recent significant progress in photonic applications.
基金supported by the National Key R&D Program of China(No.2022YFE0140100)the National Natural Science Foundation of China(Nos.52273271 and 62321004)partly supported by the Key R&D Program of Guangdong Province(No.2020B01074003)。
文摘In the present work,the high uniform 6-inch single-crystalline AlN template is successfully achieved by high temperature annealing technique,which opens up the path towards industrial application in power device.Moreover,the outstanding crystalline-quality is confirmed by Rutherford backscattering spectrometry(RBS).In accompanied with the results from X-ray diffraction,the RBS results along both[0001]and[1213]reveal that the in-plane lattice is effectively reordered by high temperature annealing.In addition,the constantΦ_(epi)angle between[0001]and[1213]at different depths of 31.54°confirms the uniform compressive strain inside the AlN region.Benefitting from the excellent crystalline quality of AlN template,we can epitaxially grow the enhanced-mode high electron mobility transistor(HEMT)with a graded AlGaN buffer as thin as only~300 nm.Such an ultra-thin AlGaN buffer layer results in the wafer-bow as low as 18.1μm in 6-inch wafer scale.The fabricated HEMT devices with 16μm-L_(GD)exhibits a threshold voltage(V_(TH))of 1.1 V and a high OFF-state breakdown voltage(V_(BD))over 1400 V.Furthermore,after 200 V high-voltage OFF-state stress,the current collapse is only 13.6%.Therefore,the advantages of both 6-inch size and excellent crystallinity announces the superiority of single-crystalline AlN template in low-cost electrical power applications.
基金the National Natural Science Foundation of China(Nos.51575389,51761135106)National Key Research and Development Program of China(2016YFB1102203)+1 种基金State key laboratory of precision measuring technology and instruments(Piltl705)the‘111’Project by the State Administration of Foreign Experts Affairs and the Ministry of Education of China(Grant No.B07014)。
文摘Color centers in silicon carbide(SiC)are promising candidates for quantum technologies.However,the richness of the polytype and defect configuration of SiC makes the accurate control of the types and position of defects in SiC still challenging.In this study,helium ion-implanted 4H-SiC was characterized by atomic force microscopy(AFM),confocal photoluminescence(PL),and confocal Raman spectroscopy at room temperature.PL signals of silicon vacancy were found and analyzed using 638-nm and 785-nm laser excitation by means of depth profiling and SWIFT mapping.Lattice defects(C-C bond)were detected by continuous laser excitation at 532 nm and 638 nm,respectively.PL/Raman depth profiling was helpful in revealing the three-dimensional distribution of produced defects.Differences in the depth profiling results and SRIM simulation results were explained by considering the depth resolution of the confocal measurement setup,helium bubbles,as well as swelling.
文摘Contrary to the common belief that the light-induced halide ion segregation in a mixed halide alloy occurs within the illuminated area,we find that the Br ions released by light are expelled from the illuminated area,which generates a macro/mesoscopic size anion ring surrounding the illuminated area,exhibiting a photoluminescence ring.This intriguing phenomenon can be explained as resulting from two counter-balancing effects:the outward diffusion of the light-induced free Br ions and the Coulombic force between the anion deficit and surplus region.Right after removing the illumination,the macro/mesoscopic scale ion displacement results in a built-in voltage of about 0.4 V between the ring and the center.Then,the displaced anions return to the illuminated area,and the restoring force leads to a damped ultra-low-frequency oscillatory ion motion,with a period of about 20-30 h and lasting over 100 h.This finding may be the first observation of an ionic plasma oscillation in solids.Our understanding and controlling the"ion segregation"demonstrate that it is possible to turn this commonly viewed"adverse phenomenon"into novel electronic applications,such as ionic patterning,self-destructive memory,and energy storage.
基金funding from the Adolf Messer Stiftungthe Friedrich-Ebert Stiftung+5 种基金the Rosa Luxemburg Stiftungthe EU-funded action H2020-MSCA-ITN-2015-ETN CELTAfunded by the Deutsche Forschungsgemeinschaft(DFG project RO 770/40)support via the BMBF projects 05K16ODA,05K16ODC,05K19ODA,and 05K19ODBfunding from the Swedish Research Council(grant no.2017.-04504)funding from the Academy of Finland(grant nos.325810,312297,320167,and 314810).
文摘Plasma waves play an important role in many solid-state phenomena and devices.They also become significant in electronic device structures as the operation frequencies of these devices increase.A prominent example is field-effect transistors(FETs),that witness increased attention for application as rectifying detectors and mixers of electromagnetic waves at gigahertz and terahertz frequencies,where they exhibit very good sensitivity even high above the cut-off frequency defined by the carrier transit time.Transport theory predicts that the coupling of radiation at THz frequencies into the channel of an antenna-coupled FET leads to the development of a gated plasma wave,collectively involving the charge carriers of both the two-dimensional electron gas and the gate electrode.In this paper,we present the first direct visualization of these waves.Employing graphene FETs containing a buried gate electrode,we utilize near-field THz nanoscopy at room temperature to directly probe the envelope function of the electric field amplitude on the exposed graphene sheet and the neighboring antenna regions.Mapping of the field distribution documents that wave injection is unidirectional from the source side since the oscillating electrical potentials on the gate and drain are equalized by capacitive shunting.The plasma waves,excited at 2 THz,are overdamped,and their decay time lies in the range of 25-70 fs.Despite this short decay time,the decay length is rather long,i.e.,0.3-0.5μm,because of the rather large propagation speed of the plasma waves,which is found to lie in the range of 3.5-7×10^(6)m/s,in good agreement with theory.The propagation speed depends only weakly on the gate voltage swing and is consistent with the theoretically predicted 1/4 power law.
基金S.-H.Y.acknowledges the funding support from the National Natural Science Foundation of China(grant nos.21431006 and 21761132008)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(grant no.21521001)+2 种基金Key Research Program of Frontier Sciences,CAS(grant no.QYZDJ-SSW-SLH036)the Users with Excellence and Scientific Research Grant of Hefei Science Center of CAS(grant no.2015HSC-UE007)O.G.S.is appreciative of the financial support from the Leibniz Program of the German Research Foundation.
文摘Three-dimensional(3D)graphene networks are performance boosters for functional nanostructures in energy-related fields.Although tremendous intriguing nanostructures-decorated 3D graphene networks have been realized,on-demand decoration of nanostructures in the specified position of interest within the whole 3D graphene skeleton is still out of reach,shedding limitations on constructing more sophisticated components with programmable structures which offer enormous potential for the enhancement of performance and exploration of new functions.Here,we report the melamine-sponge(MS)-templated hydrothermal method capable of realizing reduced graphene oxide(RGO)-nanostructure composite aerogels with programmable structures and compositions.The key of this method is using the MS template to preset the structures of choice through programmable solution-processed immobilization of graphene oxide(GO)and nanostructures.Remarkably,the hydrothermal treatment simultaneously removed the MS template and reduced the GO networks without changing the preset structures.We showcased nine typical RGO-nanostructures composite aerogels to demonstrate the versatility of the MS-templated hydrothermal method.
基金We are grateful to the Academy of Finland for the support under Projects No.286279 and 311058.
文摘Successful application of two-dimensional transition metal dichalcogenides in optoelectronic,catalytic,or sensing devices heavily relies on the materials’quality,that is,the thickness uniformity,presence of grain boundaries,and the types and concentrations of point defects.Raman spectroscopy is a powerful and nondestructive tool to probe these factors but the interpretation of the spectra,especially the separation of different contributions,is not straightforward.Comparison to simulated spectra is beneficial,but for defective systems first-principles simulations are often computationally too expensive due to the large sizes of the systems involved.Here,we present a combined first-principles and empirical potential method for simulating Raman spectra of defective materials and apply it to monolayer MoS_(2) with random distributions of Mo and S vacancies.We study to what extent the types of vacancies can be distinguished and provide insight into the origin of different evolutions of Raman spectra upon increasing defect concentration.We apply to our simulated spectra the phonon confinement model used in previous experiments to assess defect concentrations,and show that the simplest form of the model is insufficient to fully capture peak shapes,but a good match is obtained when the type of phonon confinement and the full phonon dispersion relation are accounted for.
文摘In this study,we unveil a conceptual technology for fabricating artificial metalloenzymes(ArMs)by deeply integrating hemin into protein scaffolds via a protein refolding process,a method that transcends the conventional scope of surface-level modifications.Our approach involves denaturing proteins,such as benzaldehyde lyase,green fluorescent protein,and Candida antarctica lipase B,to expose extensive reactive amino acid residues,which are then intricately linked with hemin using orthogonal click reactions,followed by protein refolding.This process not only retains the proteins’structural integrity but expands proteins’functionality.The most notable outcome of this methodology is the hemin@BAL variant,which demonstrated a remarkable 83.7%conversion rate in cyclopropanation reactions,far surpassing the capabilities of traditional hemin-based catalysis in water.This success highlights the significant role of protein structure in the ArMs’activity and marks a substantial leap forward in chemical modification of proteins.Our findings suggest vast potentials of protein refolding approaches for ArMs across various catalytic applications,paving the way for future advancements in synthetic biology and synthetic chemistry.
基金The support by R.Bottger and the Ion Beam Center(IBC)at HZDR is gratefully acknowledged.
文摘Phase-stable electromagnetic pulses in the THz frequency range offer several unique capabilities in time-resolved spectroscopy.However,the diversity of their application is limited by the covered spectral bandwidth.In particular,the upper frequency limit of photoconductive emitters-the most widespread technique in THz spectroscopy-reaches only up to 7 THz in the regular transmission mode due to absorption by infrared-active optical phonons.Here,we present ultrabroadband(extending up to 70 THz)THz emission from an Au-implanted Ge emitter that is compatible with mode-locked fibre lasers operating at wavelengths of 1.1 and 1.55μm with pulse repetition rates of 10 and 20 MHz,respectively.This result opens up the possibility for the development of compact THz photonic devices operating up to multi-THz frequencies that are compatible with Si CMOS technology.
