Flexible photodetectors have garnered significant attention by virtue of their potential applications in environmental monitoring,wearable healthcare,imaging sensing,and portable optical communications.Perovskites sta...Flexible photodetectors have garnered significant attention by virtue of their potential applications in environmental monitoring,wearable healthcare,imaging sensing,and portable optical communications.Perovskites stand out as particularly promising materials for photodetectors,offering exceptional optoelectronic properties,tunable band gaps,low-temperature solution processing,and notable mechanical flexibility.In this review,we explore the latest progress in flexible perovskite photodetectors,emphasizing the strategies developed for photoactive materials and device structures to enhance optoelectronic performance and stability.Additionally,we discuss typical applications of these devices and offer insights into future directions and potential applications.展开更多
The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied...The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration,the impact of cations or anions is not individually explored,which hinders the evaluation of different cations and further application of doping strategy.Here we report that a special group of sulfonic anions(like CF_(3)SO_(3)^(-))successfully introduce alkaline earth ions(like Ca^(2+))into perovskite lattice compared to its halide counterparts.Furthermore,with effective crystallization regulation and defect passivation of sulfonic anions,perovskite with Ca(CF_(3)SO_(3))_(2)shows reduced PbI2 residue and metallic Pb0 defects;thereby,corresponding PSCs show an enhanced PCE of 24.95%.Finally by comparing the properties of perovskite with Ca(CF_(3)SO_(3))_(2)and FACF_(3)SO_(3),we found that doped Ca^(2+)significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF_(3)SO_(3))_(2-)doped PSCs,while no obvious impact of Ca^(2+)on trap density is observed.Combining the benefits of cations and anions,this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.展开更多
Brain-computer interfaces(BCIs)represent an emerging technology that facilitates direct communication between the brain and external devices.In recent years,numerous review articles have explored various aspects of BC...Brain-computer interfaces(BCIs)represent an emerging technology that facilitates direct communication between the brain and external devices.In recent years,numerous review articles have explored various aspects of BCIs,including their fundamental principles,technical advancements,and applications in specific domains.However,these reviews often focus on signal processing,hardware development,or limited applications such as motor rehabilitation or communication.This paper aims to offer a comprehensive review of recent electroencephalogram(EEG)-based BCI applications in the medical field across 8 critical areas,encompassing rehabilitation,daily communication,epilepsy,cerebral resuscitation,sleep,neurodegenerative diseases,anesthesiology,and emotion recognition.Moreover,the current challenges and future trends of BCIs were also discussed,including personal privacy and ethical concerns,network security vulnerabilities,safety issues,and biocompatibility.展开更多
This research delves into controlling the interplay of magnetostatic field and anisotropy field via controlled composition distribution,thereby boosting coercivity in Nd-Ce-Fe-B magnets.As the originally heterogeneous...This research delves into controlling the interplay of magnetostatic field and anisotropy field via controlled composition distribution,thereby boosting coercivity in Nd-Ce-Fe-B magnets.As the originally heterogeneous compositions gradually homogenize within the magnet,an interesting trend in coercivity emerges.Initially,coercivity shows a positive trend,increasing as the components start to blend.However,after reaching an optimal point,it begins to decline.Notably,coercivity peaks once the element Ce permeates to the magnet's surfaces.This phenomenon is closely associated with changes in the H_(crit) distribution.H_(crit) is a measure that reflects the interaction between anisotropy field and magnetostatic field.When the composition becomes more uniform,the distribution of H_(crit) shifts,and its minimum absolute value varies.These changes are driven by the combined influence of anisotropy field and magnetostatic field.Understanding these relationships provides valuable insights.It opens up new avenues for enhancing coercivity in Nd-Ce-Fe-B magnets by adjusting and fine-tuning the interactions between these fields.展开更多
Due to its broken out-of-plane symmetry,z-cut periodically poled lithium niobate(PPLN)has exhibited ultrahigh second-order optical nonlinearity.Precise quantification of the domain structure of z-cut PPLN plays a crit...Due to its broken out-of-plane symmetry,z-cut periodically poled lithium niobate(PPLN)has exhibited ultrahigh second-order optical nonlinearity.Precise quantification of the domain structure of z-cut PPLN plays a critical role during poling fabrication.To enhance the imaging detection efficiency of the domain structure in z-cut PPLN,we have developed a second-harmonic generation microscope system specifically designed to produce a longitudinal electric field in foci for the imaging domain inversion.We demonstrated that imaging using a longitudinal electric field can achieve a contrast ratio enhancement by a factor of 1.77,showing high imaging efficiency and making the proposed method suitable for in situ monitoring of the z-cut PPLN poling process.展开更多
The quasiparticle scattering processes of the topological surface state(TSS)in three-dimensional topological insulators(TIs)have a vital effect on the many-body interactions and potential applications of topological m...The quasiparticle scattering processes of the topological surface state(TSS)in three-dimensional topological insulators(TIs)have a vital effect on the many-body interactions and potential applications of topological materials.In this study,we performed high-resolution temperature-dependent angle-resolved photoemission spectroscopy analysis of the 3D strong TI Bi_(2)Se_(3).Using an ab initio simulation,we analyzed the temperature dependence of the electronic structure and lifetime broadening of the TSS,which are closely associated with the quasiparticle scattering process,i.e.,electron–phonon coupling and spin-dependent scattering.We show that,at a low temperature(7 K),the spin-dependent electron scattering facilitates the anisotropic scattering rate of the TSS.Conversely,at room temperature(300 K),the electron–phonon coupling dominates the contribution to the scattering rate.The scattering rate increases with temperature and becomes uniform in momentum space owing to the temperature dependence of quasiparticle scattering.The quantitative study of temperature-dependent scattering rates in TSS is crucial to understanding the topological property and transport mobility of Dirac fermions for fundamental studies and potential applications.展开更多
The regulation of magnetic ordering and its precisely tailored thermal expansion properties in magnetic materials are ongoing hot topics,urgently demanded by modern industries.Owing to its strongly distance-dependent ...The regulation of magnetic ordering and its precisely tailored thermal expansion properties in magnetic materials are ongoing hot topics,urgently demanded by modern industries.Owing to its strongly distance-dependent complex magnetic structure,the properties of Ce_(2)Fe_(17)intermetallic compound are highly sensitive to the preparation process and a series of multi-physical fields including pressure,temperature,and magnetic fields.Here,we introduced tensile stress into Ce_(2)Fe_(17)using a high-energy ball milling method.Both static and high-frequency magnetic measurements revealed stress-induced room-temperature ferromagnetic ordering in Ce_(2)Fe_(17),with the magnetization showing a nearly linear relationship with strain as milling time varies.Complementary neutron diffraction and Mossbauer spectroscopy confirmed that ball milling eliminated the helical magnetic ordering and enhanced the ferromagnetic ordering,resulting in room-temperature ferromagnetism in Ce_(2)Fe_(17).Due to the inhomogeneous strain and short-range ferromagnetic ordering caused by ball milling,Ce_(2)Fe_(17)exhibits a near-zero thermal expansion behavior(α=-1.70×10^(-6)K^(-1))over a wide temperature range(100-225 K),making it a promising candidate for zero thermal expansion materials.This work highlights that strain control via high-energy ball milling is a feasible and scalable strategy for tuning the magnetic interactions and the interplay between lattice structure and magnetic ordering in intermetallic compounds.展开更多
ThMn_(12)-type iron-rich rare-earth permanent magnetic materials have garnered significant attention due to their exceptional intrinsic magnetic properties.However,challenges such as the metastable nature of the ThMn1...ThMn_(12)-type iron-rich rare-earth permanent magnetic materials have garnered significant attention due to their exceptional intrinsic magnetic properties.However,challenges such as the metastable nature of the ThMn12-type phase,excessively small single-domain grain size,and complex fabrication processes have hindered the achievement of high phase purity,uniform microstructure,and desirable extrinsic performance.In this study,we directly synthesized ThMn_(12)-type Sm_(0.8)Zr_(0.2)Fe_(11)SiB_(x)(x=0-0.2)ribbon magnets via boron doping combined with a one-step rapid solidification method.This approach not only simplifies the fabrication process but also enhances phase stability and achieves a uniform microstructure with high ThMn12-type phase purity.By optimizing the boron content and cooling rate,the resulting magnets exhibit a coercivity(H_(c))of 6222 Oe,a remanence(M_(r))of 80 emu/g,and a remanence ratio(M_(r)/M_(s))of 0.71.This work demonstrates a streamlined approach to producing high-performance ThMn12-type magnets and provides insights into their practical application potential.展开更多
High-efficiency formamidinium lead iodide(FAPbI3)-based perovskite solar cells(PSCs)typically involve annealing in humid air during the fabrication process of perovskite films.However,the combined effects of humidity ...High-efficiency formamidinium lead iodide(FAPbI3)-based perovskite solar cells(PSCs)typically involve annealing in humid air during the fabrication process of perovskite films.However,the combined effects of humidity and relatively high temperature often result in the uncontrollable formation of a detrimental PbI_(2)phase in the perovskite films.As a result,the annealing process of perovskite films is highly sensitive to the relative humidity fluctuations of the environment.Under solar illumination,the undesired PbI_(2)tends to decompose,accelerating the degradation of perovskite materials and severely compromising the light stability of PSCs.This issue is particularly critical for the buried interface and bulk of the perovskite films,as these regions absorb the majority of the incident light.Pre-treatment and posttreatment strategies are generally confined to address the PbI_(2)issues at the buried interface and on the surface of the perovskite films,respectively.However,effectively addressing the effects of excess PbI_(2)at buried interface and grain boundaries within bulk in a single step remains challenging.In this study,we propose an intermediate-treatment strategy using phthalylglycyl chloride(PTC),which involves treating the wet films with PTC prior to annealing during the formation process of the perovskite films.This approach protects the grain boundaries of polycrystalline perovskite films in advance,effectively preventing moisture-induced degradation of the perovskites and thus significantly broadening the relative humidity window of annealing process.Our results demonstrate that this strategy can successfully suppress the formation of PbI_(2)at the grain boundaries and buried interface of perovskite films,thereby eliminating the PbI_(2)-induced degradation pathways.Our strategy significantly reduces the sensitivity to humidity fluctuations during annealing for fabricating stable PSCs,ensuring more consistent fabrication of stable PSCs.Consequently,the resulting PSCs achieve a champion power conversion efficiency of 26.1% and demonstrate excellent light stability.展开更多
Local precise drug delivery is conducive to improving therapeutic efficacy and minimizing off-target toxicity.Current local delivery approaches are focused mostly on superficial or postoperative tumor lesions,due to t...Local precise drug delivery is conducive to improving therapeutic efficacy and minimizing off-target toxicity.Current local delivery approaches are focused mostly on superficial or postoperative tumor lesions,due to the challenges posed by the inaccessibility of deep-seated tumors.Herein,we report a magnetic continuum soft robot capable of non-invasive and site-specific delivery of prodrug nanoassemblies-loaded hydrogel.The nanoassemblies are co-assembled from redox-responsive docetaxel prodrug and oxaliplatin prodrug,and subsequently embedded into a hydrogel matrix.The hydrogel precursor and crosslinker are synchronously delivered using the soft robot under magnetic guidance and in situ crosslinked at the gastric cancer lesions,forming a drug depot for sustained release and long-lasting treatment.As the hydrogel gradually degrades,the nanoassemblies are internalized by tumor cells.The redox response ability enables them to be selectively activatedwithin tumor cells to trigger the release of docetaxel and oxaliplatin,exerting a synergistic anti-tumor effect.We find that the combination effectively induces immunogenic cell death of gastric tumor,enhancing antitumor immune responses.This strategy offers an intelligent and controllable integration platform for precise drug delivery and combined chemo-immunotherapy.展开更多
Piezoelectric nanogenerators(PENGs) are evolving as next-generation energy harvesters due to their self-powered sensing,multi-stimuli-responsiveness,and wearable electronics.Here,we present a flexible PENG utilizing e...Piezoelectric nanogenerators(PENGs) are evolving as next-generation energy harvesters due to their self-powered sensing,multi-stimuli-responsiveness,and wearable electronics.Here,we present a flexible PENG utilizing electro spun poly(vinylidene fluoride trifluoroethylene)(P(VDF-TrFE)) nanofibers.By optimizing the rotational speeds during the electrospinning process,we have achieved nanofibers with a highly aligned structure and uniform polarβ-phase,an enhancement of piezoelectric response,particularly in terms of sensitivity and power generation.The longitudinal piezoelectric coefficient(d_(33)) reaches-21.6 pC·N^(-1).The transverse piezoelectric measurement yields an output of 26 V and 38.6 nA.The device exhibits an ultra-high sensitivity of 5.76 V·kPa^(-1),surpassing previously reported values by orders of magnitude.The PENG is successfully employed for Braille recognition and the precise manipulation of a robotic hand,indicating its efficacy for tactile interaction systems.This study presents a novel approach to facilitating intelligent human-machine interaction by exploiting the unique properties of organic piezoelectric materials.展开更多
In order to push the grating-based phase contrast imaging system to be used in hospitM and laboratories, this paper designs and develops a novel structure of x-ray scintillator functioning also as an analyser grating,...In order to push the grating-based phase contrast imaging system to be used in hospitM and laboratories, this paper designs and develops a novel structure of x-ray scintillator functioning also as an analyser grating, which has been proposed for grating-based x-ray differential phase contrast imaging. According to this design, the scintillator should have a periodical structure in one dimension with the pitch equaling the period of self-image of the phase grating at the Talbot distance, where one half of the pitch is pixellated and is made of x-ray sensitive fluorescent material, such as CsI（T1）, and the remaining part of the pitch is made of x-ray insensitive material, such as silicon. To realize the design, a deep pore array with a high aspect ratio and specially designed grating pattern are successfully manufactured on 5 inch silicon wafer by the photo-assisted electrochemical etching method. The related other problems, such as oxidation-caused geometrical distortion, the filling of CsI（T1） into deep pores and the removal of inside bubbles, have been overcome. Its pixel size, depth and grating pitch are 3 p.m^7.5 ~m, 150 p^m and 3 Ixm, respectively. The microstructure of the scintillator has been examined microscopically and macroscopically by scanning electron microscope and x-ray resolution chart testing, respectively. The preliminary measurements have shown that the proposed scintillator, also functioning as an analyser grating, has been successfully designed and developed.展开更多
Zinc aluminium(Zn-Al)and lithium aluminium(Li-Al)–layered double hydroxides(LDH)coatings with incorporated inhibitors(Li-,Mo-and W-based)were successfully synthesized on AZ31 Mg alloy.Zn-Al LDH W and Li-Al LDH Li sho...Zinc aluminium(Zn-Al)and lithium aluminium(Li-Al)–layered double hydroxides(LDH)coatings with incorporated inhibitors(Li-,Mo-and W-based)were successfully synthesized on AZ31 Mg alloy.Zn-Al LDH W and Li-Al LDH Li showed the highest corrosion resistance and were selected for further evaluation.SEM cross-section examination revealed a bi-layer structure composed of an outer part with loose flakes and a denser inner layer.XRD,FTIR,and XPS analysis confirmed the incorporation of the inhibitors.Post-treatments with corrosion inhibitors containing solutions resulted in the selective dissolution of the most external layer of the LDH coating,reducing the surface roughness,hydrophilicity and paint adhesion of the layers.Active corrosion properties were confirmed by SVET evaluation for the Zn-Al LDH W coating.The proposed active corrosion mechanism involves the ion-exchange of aggressive Cl-ions,deposition of hydroxides and competitive adsorption of W-rich corrosion inhibitors.展开更多
Large-scale growth and heterogeneous integration with existing semiconductors are the main obstacles to the application of metal halide perovskites in optoelectronics.Herein,a universal vacuum evaporation strategy is ...Large-scale growth and heterogeneous integration with existing semiconductors are the main obstacles to the application of metal halide perovskites in optoelectronics.Herein,a universal vacuum evaporation strategy is presented to prepare copper halide films with wafer-scale spatial homogeneity.Benefiting from the electric field manipulation method,the built-in electric fields are optimized and further boost the self-powered UV photodetecting performances of common wide-bandgap semiconductors by more than three orders of magnitude.Furthermore,with effective modulation of the interfacial charge dynamics,the as-fabricated GaN-substrate heterojunction photodetector demonstrates an ultrahigh on/off ratio exceeding 107,an impressive responsivity of up to 256 mA W^(-1),and a remarkable detectivity of 2.16×10^(13) Jones at 350 nm,0 V bias.Additionally,the device exhibits an ultrafast response speed(t r/t d=716 ns/1.30 ms),an ultra-narrow photoresponse spectrum with an FWHM of 18 nm and outstanding continuous operational stability as well as long-term stability.Subsequently,a 372-pixel light-powered imaging sensor array with the coefficient of variation of photocurrents reducing to 5.20%is constructed,which demonstrates exceptional electrical homogeneity,operational reliability,and UV imaging capability.This strategy provides an efficient way for large-scale integration of metal halide perovskites with commercial semiconductors for miniature optoelectronic devices.展开更多
Perovskite solar cells have reached a power-conversion efficiency(PCE) of 25.6%,showing great potential with reliable moisture and heat stability.Most results are achieved on small-area devices,using conventional thin...Perovskite solar cells have reached a power-conversion efficiency(PCE) of 25.6%,showing great potential with reliable moisture and heat stability.Most results are achieved on small-area devices,using conventional thin-film processing technologies like spin-coating method.However,such approaches may not be upscaled for large-area substrates.Thus,strategies and materials need to be developed for manufacturing processing routes to realize future commercial photovoltaic fabrications.Notable results have been achieved on large-area perovskite solar cells.In this review,similarities and differences of large-area perovskite fabrication mechanisms between the various pathways are investigated,especially on the parameters affecting the nucleation and crystal growth kinetics.Moreover,the methods for large-area transporting layers and electrodes are discussed,and some key issues from cells to modules.Challenges and opportunities are proposed to pave the way of high-efficiency perovskite solar modules.展开更多
Interface engineering is proved to be the most important strategy to push the device performance of the perovskite solar cell(PSC) to its limit, and numerous works have been conducted to screen efficient materials. He...Interface engineering is proved to be the most important strategy to push the device performance of the perovskite solar cell(PSC) to its limit, and numerous works have been conducted to screen efficient materials. Here, on the basis of the previous studies, we employ machine learning to map the relationship between the interface material and the device performance, leading to intelligently screening interface materials towards minimizing voltage losses in p-i-n type PSCs. To enhance the explainability of the machine learning models, molecular descriptors are used to represent the materials. Furthermore,experimental analysis with different characterization methods and device simulation based on the drift-diffusion physical model are conducted to get physical insights and validate the machine learning models. Accordingly, 3-thiophene ethylamine hydrochloride(Th EACl) is screened as an example, which enables remarkable improvements in VOCand PCE of the PSCs. Our work reveals the critical role of datadriven analysis in the high throughput screening of interface materials, which will significantly accelerate the exploration of new materials for high-efficiency PSCs.展开更多
In broadband coherent anti-Stokes Raman scattering （CARS） spectroscopy with supercontinuum （SC）, the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of variou...In broadband coherent anti-Stokes Raman scattering （CARS） spectroscopy with supercontinuum （SC）, the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of various spectral components of SC in an enough bandwidth. By numerical simulations, the optimal experimental conditions for improving the SC are obtained. The broadband time-resolved CARS spectrography based on the SC with required temporal and spectral distributions is realised. The global molecular vibrational spectrum with well suppressed nonresonant background noise can be obtained in a single measurement. At the same time, the measurements of dephasing times of various molecular vibrational modes can be conveniently achieved from intensities of a sequence of time-resolved CARS signals. It will be more helpful to provide a complete picture of molecular vibrations, and to exhibit a potential to understand not only both the solvent dynamics and the solute-solvent interactions, but also the mechanisms of chemical reactions in the fields of biology, chemistry and material science.展开更多
The performance of the metal halide perovskite solar cells(PSCs)highly relies on the experimental parameters,including the fabrication processes and the compositions of the perovskites;tremendous experimental work has...The performance of the metal halide perovskite solar cells(PSCs)highly relies on the experimental parameters,including the fabrication processes and the compositions of the perovskites;tremendous experimental work has been done to optimize these factors.However,predicting the device performance of the PSCs from the fabrication parameters before experiments is still challenging.Herein,we bridge this gap by machine learning(ML)based on a dataset including 1072 devices from peer-reviewed publications.The optimized ML model accurately predicts the PCE from the experimental parameters with a root mean square error of 1.28%and a Pearson coefficientr of 0.768.Moreover,the factors governing the device performance are ranked by shapley additive explanations(SHAP),among which,A-site cation is crucial to getting highly efficient PSCs.Experiments and density functional theory calculations are employed to validate and help explain the predicting results by the ML model.Our work reveals the feasibility of ML in predicting the device performance from the experimental parameters before experiments,which enables the reverse experimental design toward highly efficient PSCs.展开更多
Inorganic lead halide perovskite nanocrystals(NCs)with superior photoelectric properties are expected to have excellent performance in many fields.However,the anion exchange changes their features and is unfavorable f...Inorganic lead halide perovskite nanocrystals(NCs)with superior photoelectric properties are expected to have excellent performance in many fields.However,the anion exchange changes their features and is unfavorable for their applications in many fields.Hence,impeding anion exchange is important for improving the composition stability of inorganic lead halide perovskite NCs.Herein,CsPb X3(X=Cl,Br)NCs are coated with Cs4PbX6 shell to impede anion exchange and reduce anion mobility.The Cs4PbX6 shell is facily fabricated on CsPbX3 NCs through high temperature injection method.Anion exchange experiments demonstrate that the Cs4 PbX6 shell completely encapsulates CsPbX3 NCs and greatly improves the composition stability of CsPbX3 NCs.Moreover,our work also sheds light on the potential design approaches of various heterostructures to expand the application of CsPbM3(M=Cl,Br,I)NCs.展开更多
基金supported by the grants from the National Key Research and Development Program of China 2023YFC2505900support from State Key Laboratory of Photovoltaic Science and Technology 202401030303.
文摘Flexible photodetectors have garnered significant attention by virtue of their potential applications in environmental monitoring,wearable healthcare,imaging sensing,and portable optical communications.Perovskites stand out as particularly promising materials for photodetectors,offering exceptional optoelectronic properties,tunable band gaps,low-temperature solution processing,and notable mechanical flexibility.In this review,we explore the latest progress in flexible perovskite photodetectors,emphasizing the strategies developed for photoactive materials and device structures to enhance optoelectronic performance and stability.Additionally,we discuss typical applications of these devices and offer insights into future directions and potential applications.
基金support from the National Key Research and Development Program of China(No.2022YFE0137400)the National Natural Science Foundation of China(Grant No.62274040).
文摘The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration,the impact of cations or anions is not individually explored,which hinders the evaluation of different cations and further application of doping strategy.Here we report that a special group of sulfonic anions(like CF_(3)SO_(3)^(-))successfully introduce alkaline earth ions(like Ca^(2+))into perovskite lattice compared to its halide counterparts.Furthermore,with effective crystallization regulation and defect passivation of sulfonic anions,perovskite with Ca(CF_(3)SO_(3))_(2)shows reduced PbI2 residue and metallic Pb0 defects;thereby,corresponding PSCs show an enhanced PCE of 24.95%.Finally by comparing the properties of perovskite with Ca(CF_(3)SO_(3))_(2)and FACF_(3)SO_(3),we found that doped Ca^(2+)significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF_(3)SO_(3))_(2-)doped PSCs,while no obvious impact of Ca^(2+)on trap density is observed.Combining the benefits of cations and anions,this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.
基金supported by the National Key R&D Program of China(2021YFF1200602)the National Science Fund for Excellent Overseas Scholars(0401260011)+3 种基金the National Defense Science and Technology Innovation Fund of Chinese Academy of Sciences(c02022088)the Tianjin Science and Technology Program(20JCZDJC00810)the National Natural Science Foundation of China(82202798)the Shanghai Sailing Program(22YF1404200).
文摘Brain-computer interfaces(BCIs)represent an emerging technology that facilitates direct communication between the brain and external devices.In recent years,numerous review articles have explored various aspects of BCIs,including their fundamental principles,technical advancements,and applications in specific domains.However,these reviews often focus on signal processing,hardware development,or limited applications such as motor rehabilitation or communication.This paper aims to offer a comprehensive review of recent electroencephalogram(EEG)-based BCI applications in the medical field across 8 critical areas,encompassing rehabilitation,daily communication,epilepsy,cerebral resuscitation,sleep,neurodegenerative diseases,anesthesiology,and emotion recognition.Moreover,the current challenges and future trends of BCIs were also discussed,including personal privacy and ethical concerns,network security vulnerabilities,safety issues,and biocompatibility.
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFB3505200 and 2023YFB3507000)Inner Mongolia Northern Rare Earth Advanced Materials Technology Innovation Co.,Ltd.Project(No.CXZX-B-202304-0004)
文摘This research delves into controlling the interplay of magnetostatic field and anisotropy field via controlled composition distribution,thereby boosting coercivity in Nd-Ce-Fe-B magnets.As the originally heterogeneous compositions gradually homogenize within the magnet,an interesting trend in coercivity emerges.Initially,coercivity shows a positive trend,increasing as the components start to blend.However,after reaching an optimal point,it begins to decline.Notably,coercivity peaks once the element Ce permeates to the magnet's surfaces.This phenomenon is closely associated with changes in the H_(crit) distribution.H_(crit) is a measure that reflects the interaction between anisotropy field and magnetostatic field.When the composition becomes more uniform,the distribution of H_(crit) shifts,and its minimum absolute value varies.These changes are driven by the combined influence of anisotropy field and magnetostatic field.Understanding these relationships provides valuable insights.It opens up new avenues for enhancing coercivity in Nd-Ce-Fe-B magnets by adjusting and fine-tuning the interactions between these fields.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFC3401100 and 2022YFF0712500)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030009)+2 种基金the National Natural Science Foundation of China(Grant Nos.12204017,12004012,12004013,12041602,91750203,91850111,and 92150301)the China Postdoctoral Science Foundation(Grant No.2020M680220 and 2020M680230)the Clinical Medicine Plus X-Young Scholars Project,Peking University,Fundamental Research Funds for the Central Universities.
文摘Due to its broken out-of-plane symmetry,z-cut periodically poled lithium niobate(PPLN)has exhibited ultrahigh second-order optical nonlinearity.Precise quantification of the domain structure of z-cut PPLN plays a critical role during poling fabrication.To enhance the imaging detection efficiency of the domain structure in z-cut PPLN,we have developed a second-harmonic generation microscope system specifically designed to produce a longitudinal electric field in foci for the imaging domain inversion.We demonstrated that imaging using a longitudinal electric field can achieve a contrast ratio enhancement by a factor of 1.77,showing high imaging efficiency and making the proposed method suitable for in situ monitoring of the z-cut PPLN poling process.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1604301)the Natural Science Foundation of China(Grant Nos.12334013,12204018,9205020192250306)。
文摘The quasiparticle scattering processes of the topological surface state(TSS)in three-dimensional topological insulators(TIs)have a vital effect on the many-body interactions and potential applications of topological materials.In this study,we performed high-resolution temperature-dependent angle-resolved photoemission spectroscopy analysis of the 3D strong TI Bi_(2)Se_(3).Using an ab initio simulation,we analyzed the temperature dependence of the electronic structure and lifetime broadening of the TSS,which are closely associated with the quasiparticle scattering process,i.e.,electron–phonon coupling and spin-dependent scattering.We show that,at a low temperature(7 K),the spin-dependent electron scattering facilitates the anisotropic scattering rate of the TSS.Conversely,at room temperature(300 K),the electron–phonon coupling dominates the contribution to the scattering rate.The scattering rate increases with temperature and becomes uniform in momentum space owing to the temperature dependence of quasiparticle scattering.The quantitative study of temperature-dependent scattering rates in TSS is crucial to understanding the topological property and transport mobility of Dirac fermions for fundamental studies and potential applications.
基金financially supported by the National Key Research and Development Program of China(Nos.2021YFB3501301 and 2021YFB3501302)the National Natural Science Foundation of China(No.51731001)+1 种基金the Open Fund of the China Spallation Neutron Source Songshan Lake Science City(No.KFKT2023B14)the Large Scientific Facility Open Subject of Songshan Lake,Dongguan,Guangdong(No.KFKT2022A06)
文摘The regulation of magnetic ordering and its precisely tailored thermal expansion properties in magnetic materials are ongoing hot topics,urgently demanded by modern industries.Owing to its strongly distance-dependent complex magnetic structure,the properties of Ce_(2)Fe_(17)intermetallic compound are highly sensitive to the preparation process and a series of multi-physical fields including pressure,temperature,and magnetic fields.Here,we introduced tensile stress into Ce_(2)Fe_(17)using a high-energy ball milling method.Both static and high-frequency magnetic measurements revealed stress-induced room-temperature ferromagnetic ordering in Ce_(2)Fe_(17),with the magnetization showing a nearly linear relationship with strain as milling time varies.Complementary neutron diffraction and Mossbauer spectroscopy confirmed that ball milling eliminated the helical magnetic ordering and enhanced the ferromagnetic ordering,resulting in room-temperature ferromagnetism in Ce_(2)Fe_(17).Due to the inhomogeneous strain and short-range ferromagnetic ordering caused by ball milling,Ce_(2)Fe_(17)exhibits a near-zero thermal expansion behavior(α=-1.70×10^(-6)K^(-1))over a wide temperature range(100-225 K),making it a promising candidate for zero thermal expansion materials.This work highlights that strain control via high-energy ball milling is a feasible and scalable strategy for tuning the magnetic interactions and the interplay between lattice structure and magnetic ordering in intermetallic compounds.
基金Project supported by the National Key R&D Program of China(Grant Nos.2021YFB3500300 and 2023YFB3507000)the Scientific Research Foundation of the High Education Institutions for Distinguished Young Scholars in Anhui Province(Grant No.2022AH020012)+1 种基金partially supported by the Innovation Project for Overseas Researcher in Anhui Province(Grant No.2022LCX004)the facilities at the Center of Free Electron Laser&High Magnetic Field(FEL&HMF)in Anhui University。
文摘ThMn_(12)-type iron-rich rare-earth permanent magnetic materials have garnered significant attention due to their exceptional intrinsic magnetic properties.However,challenges such as the metastable nature of the ThMn12-type phase,excessively small single-domain grain size,and complex fabrication processes have hindered the achievement of high phase purity,uniform microstructure,and desirable extrinsic performance.In this study,we directly synthesized ThMn_(12)-type Sm_(0.8)Zr_(0.2)Fe_(11)SiB_(x)(x=0-0.2)ribbon magnets via boron doping combined with a one-step rapid solidification method.This approach not only simplifies the fabrication process but also enhances phase stability and achieves a uniform microstructure with high ThMn12-type phase purity.By optimizing the boron content and cooling rate,the resulting magnets exhibit a coercivity(H_(c))of 6222 Oe,a remanence(M_(r))of 80 emu/g,and a remanence ratio(M_(r)/M_(s))of 0.71.This work demonstrates a streamlined approach to producing high-performance ThMn12-type magnets and provides insights into their practical application potential.
基金financially supported by the National Natural Science Foundation of China(52203208,52325310,U24A6003,52303335)the National Key R&D Program of China(2021YFB3800101)+3 种基金the Beijing Nova Program(contract no.20230484480)the open research fund of Songshan Lake Materials Laboratory(2022SLABFK07)the Yunnan Provincial Science and Technology Project at Southwest United Graduate School(202302AO370013)the R&D Fruit Fund(20210001)。
文摘High-efficiency formamidinium lead iodide(FAPbI3)-based perovskite solar cells(PSCs)typically involve annealing in humid air during the fabrication process of perovskite films.However,the combined effects of humidity and relatively high temperature often result in the uncontrollable formation of a detrimental PbI_(2)phase in the perovskite films.As a result,the annealing process of perovskite films is highly sensitive to the relative humidity fluctuations of the environment.Under solar illumination,the undesired PbI_(2)tends to decompose,accelerating the degradation of perovskite materials and severely compromising the light stability of PSCs.This issue is particularly critical for the buried interface and bulk of the perovskite films,as these regions absorb the majority of the incident light.Pre-treatment and posttreatment strategies are generally confined to address the PbI_(2)issues at the buried interface and on the surface of the perovskite films,respectively.However,effectively addressing the effects of excess PbI_(2)at buried interface and grain boundaries within bulk in a single step remains challenging.In this study,we propose an intermediate-treatment strategy using phthalylglycyl chloride(PTC),which involves treating the wet films with PTC prior to annealing during the formation process of the perovskite films.This approach protects the grain boundaries of polycrystalline perovskite films in advance,effectively preventing moisture-induced degradation of the perovskites and thus significantly broadening the relative humidity window of annealing process.Our results demonstrate that this strategy can successfully suppress the formation of PbI_(2)at the grain boundaries and buried interface of perovskite films,thereby eliminating the PbI_(2)-induced degradation pathways.Our strategy significantly reduces the sensitivity to humidity fluctuations during annealing for fabricating stable PSCs,ensuring more consistent fabrication of stable PSCs.Consequently,the resulting PSCs achieve a champion power conversion efficiency of 26.1% and demonstrate excellent light stability.
基金supported by National Natural Science Foundation of China(No.82161138029)Liaoning Revitalization Talents Program(No.XLYC2402040)the Project of China-Japan Joint International Laboratory of Advanced Drug Delivery System Research and Translation of Liaoning Province(No.2024JH2/102100007).
文摘Local precise drug delivery is conducive to improving therapeutic efficacy and minimizing off-target toxicity.Current local delivery approaches are focused mostly on superficial or postoperative tumor lesions,due to the challenges posed by the inaccessibility of deep-seated tumors.Herein,we report a magnetic continuum soft robot capable of non-invasive and site-specific delivery of prodrug nanoassemblies-loaded hydrogel.The nanoassemblies are co-assembled from redox-responsive docetaxel prodrug and oxaliplatin prodrug,and subsequently embedded into a hydrogel matrix.The hydrogel precursor and crosslinker are synchronously delivered using the soft robot under magnetic guidance and in situ crosslinked at the gastric cancer lesions,forming a drug depot for sustained release and long-lasting treatment.As the hydrogel gradually degrades,the nanoassemblies are internalized by tumor cells.The redox response ability enables them to be selectively activatedwithin tumor cells to trigger the release of docetaxel and oxaliplatin,exerting a synergistic anti-tumor effect.We find that the combination effectively induces immunogenic cell death of gastric tumor,enhancing antitumor immune responses.This strategy offers an intelligent and controllable integration platform for precise drug delivery and combined chemo-immunotherapy.
基金fundings of National Key Research and Development program of China (No. 2021YFA1200700)National Natural Science Foundation of China (Nos. T2222025 and 62174053)+3 种基金Natural Science Foundation of Chongqing (CSTB2024NSCQ-JQX0005)Shanghai Science and Technology Innovation Action Plan (21JC1402000 and 21520714100)the Fundamental Research Funds for the Central Universitiesthe Class Ⅲ Peak Discipline of Shanghai—Materials Science and Engineering (High-Energy Beam Intelligent Processing and Green Manufacturing)。
文摘Piezoelectric nanogenerators(PENGs) are evolving as next-generation energy harvesters due to their self-powered sensing,multi-stimuli-responsiveness,and wearable electronics.Here,we present a flexible PENG utilizing electro spun poly(vinylidene fluoride trifluoroethylene)(P(VDF-TrFE)) nanofibers.By optimizing the rotational speeds during the electrospinning process,we have achieved nanofibers with a highly aligned structure and uniform polarβ-phase,an enhancement of piezoelectric response,particularly in terms of sensitivity and power generation.The longitudinal piezoelectric coefficient(d_(33)) reaches-21.6 pC·N^(-1).The transverse piezoelectric measurement yields an output of 26 V and 38.6 nA.The device exhibits an ultra-high sensitivity of 5.76 V·kPa^(-1),surpassing previously reported values by orders of magnitude.The PENG is successfully employed for Braille recognition and the precise manipulation of a robotic hand,indicating its efficacy for tactile interaction systems.This study presents a novel approach to facilitating intelligent human-machine interaction by exploiting the unique properties of organic piezoelectric materials.
基金supported by the Major Program of the National Natural Science Foundation of China (Grant No. 60532090)
文摘In order to push the grating-based phase contrast imaging system to be used in hospitM and laboratories, this paper designs and develops a novel structure of x-ray scintillator functioning also as an analyser grating, which has been proposed for grating-based x-ray differential phase contrast imaging. According to this design, the scintillator should have a periodical structure in one dimension with the pitch equaling the period of self-image of the phase grating at the Talbot distance, where one half of the pitch is pixellated and is made of x-ray sensitive fluorescent material, such as CsI（T1）, and the remaining part of the pitch is made of x-ray insensitive material, such as silicon. To realize the design, a deep pore array with a high aspect ratio and specially designed grating pattern are successfully manufactured on 5 inch silicon wafer by the photo-assisted electrochemical etching method. The related other problems, such as oxidation-caused geometrical distortion, the filling of CsI（T1） into deep pores and the removal of inside bubbles, have been overcome. Its pixel size, depth and grating pitch are 3 p.m^7.5 ~m, 150 p^m and 3 Ixm, respectively. The microstructure of the scintillator has been examined microscopically and macroscopically by scanning electron microscope and x-ray resolution chart testing, respectively. The preliminary measurements have shown that the proposed scintillator, also functioning as an analyser grating, has been successfully designed and developed.
基金the support of the RTI2018-096391-B-C33 FEDER/Ministerio de Ciencia e Innovación-Agencia Estatal de InvestigaciónS2018/NMT-4411 Regional Government of Madrid+2 种基金EU Structural and Social Funds and PID2021-124341OBC22(MCIU/AEI/FEDER,UE)the support of RYC-201721843,Ministerio de Ciencia e Innovaciónsupported by the Royal Academy of Engineering through the RAEng Research Fellowship and by EPSRC(EP/V026097/1)。
文摘Zinc aluminium(Zn-Al)and lithium aluminium(Li-Al)–layered double hydroxides(LDH)coatings with incorporated inhibitors(Li-,Mo-and W-based)were successfully synthesized on AZ31 Mg alloy.Zn-Al LDH W and Li-Al LDH Li showed the highest corrosion resistance and were selected for further evaluation.SEM cross-section examination revealed a bi-layer structure composed of an outer part with loose flakes and a denser inner layer.XRD,FTIR,and XPS analysis confirmed the incorporation of the inhibitors.Post-treatments with corrosion inhibitors containing solutions resulted in the selective dissolution of the most external layer of the LDH coating,reducing the surface roughness,hydrophilicity and paint adhesion of the layers.Active corrosion properties were confirmed by SVET evaluation for the Zn-Al LDH W coating.The proposed active corrosion mechanism involves the ion-exchange of aggressive Cl-ions,deposition of hydroxides and competitive adsorption of W-rich corrosion inhibitors.
基金financially supported by the National Natural Science Foundation of China(Nos.92263106,62204047,and 12061131009)Science and Technology Commission of Shanghai Municipality(Nos.21520712600 and 19520744300).
文摘Large-scale growth and heterogeneous integration with existing semiconductors are the main obstacles to the application of metal halide perovskites in optoelectronics.Herein,a universal vacuum evaporation strategy is presented to prepare copper halide films with wafer-scale spatial homogeneity.Benefiting from the electric field manipulation method,the built-in electric fields are optimized and further boost the self-powered UV photodetecting performances of common wide-bandgap semiconductors by more than three orders of magnitude.Furthermore,with effective modulation of the interfacial charge dynamics,the as-fabricated GaN-substrate heterojunction photodetector demonstrates an ultrahigh on/off ratio exceeding 107,an impressive responsivity of up to 256 mA W^(-1),and a remarkable detectivity of 2.16×10^(13) Jones at 350 nm,0 V bias.Additionally,the device exhibits an ultrafast response speed(t r/t d=716 ns/1.30 ms),an ultra-narrow photoresponse spectrum with an FWHM of 18 nm and outstanding continuous operational stability as well as long-term stability.Subsequently,a 372-pixel light-powered imaging sensor array with the coefficient of variation of photocurrents reducing to 5.20%is constructed,which demonstrates exceptional electrical homogeneity,operational reliability,and UV imaging capability.This strategy provides an efficient way for large-scale integration of metal halide perovskites with commercial semiconductors for miniature optoelectronic devices.
基金supported by the National Key Research and Development Program of China(Nos.2019YFA0707003 and 2019YFE0114100)the National Natural Science Foundation of China(NSFC 51872007)Beijing Municipal Natural Science Foundation(No.7202094).
文摘Perovskite solar cells have reached a power-conversion efficiency(PCE) of 25.6%,showing great potential with reliable moisture and heat stability.Most results are achieved on small-area devices,using conventional thin-film processing technologies like spin-coating method.However,such approaches may not be upscaled for large-area substrates.Thus,strategies and materials need to be developed for manufacturing processing routes to realize future commercial photovoltaic fabrications.Notable results have been achieved on large-area perovskite solar cells.In this review,similarities and differences of large-area perovskite fabrication mechanisms between the various pathways are investigated,especially on the parameters affecting the nucleation and crystal growth kinetics.Moreover,the methods for large-area transporting layers and electrodes are discussed,and some key issues from cells to modules.Challenges and opportunities are proposed to pave the way of high-efficiency perovskite solar modules.
基金supported by the National Natural Science Foundation of China (62075006)the National Key R&D Program of China (2018YFB1500200)。
文摘Interface engineering is proved to be the most important strategy to push the device performance of the perovskite solar cell(PSC) to its limit, and numerous works have been conducted to screen efficient materials. Here, on the basis of the previous studies, we employ machine learning to map the relationship between the interface material and the device performance, leading to intelligently screening interface materials towards minimizing voltage losses in p-i-n type PSCs. To enhance the explainability of the machine learning models, molecular descriptors are used to represent the materials. Furthermore,experimental analysis with different characterization methods and device simulation based on the drift-diffusion physical model are conducted to get physical insights and validate the machine learning models. Accordingly, 3-thiophene ethylamine hydrochloride(Th EACl) is screened as an example, which enables remarkable improvements in VOCand PCE of the PSCs. Our work reveals the critical role of datadriven analysis in the high throughput screening of interface materials, which will significantly accelerate the exploration of new materials for high-efficiency PSCs.
基金Project supported by the National Natural Science Foundation of China(Grant No.60627003)the Foundation for Creative Team in Institution of Higher Education of Guangdong Province,China(Grant No.06CXTD009)
文摘In broadband coherent anti-Stokes Raman scattering （CARS） spectroscopy with supercontinuum （SC）, the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of various spectral components of SC in an enough bandwidth. By numerical simulations, the optimal experimental conditions for improving the SC are obtained. The broadband time-resolved CARS spectrography based on the SC with required temporal and spectral distributions is realised. The global molecular vibrational spectrum with well suppressed nonresonant background noise can be obtained in a single measurement. At the same time, the measurements of dephasing times of various molecular vibrational modes can be conveniently achieved from intensities of a sequence of time-resolved CARS signals. It will be more helpful to provide a complete picture of molecular vibrations, and to exhibit a potential to understand not only both the solvent dynamics and the solute-solvent interactions, but also the mechanisms of chemical reactions in the fields of biology, chemistry and material science.
基金the National Natural Science Foundation of China(Grant No.62075006)the National Key Research and Development Program of China(Grant No.2021YFB3600403)the Natural Science Talents Foundation(Grant No.KSRC22001532)。
文摘The performance of the metal halide perovskite solar cells(PSCs)highly relies on the experimental parameters,including the fabrication processes and the compositions of the perovskites;tremendous experimental work has been done to optimize these factors.However,predicting the device performance of the PSCs from the fabrication parameters before experiments is still challenging.Herein,we bridge this gap by machine learning(ML)based on a dataset including 1072 devices from peer-reviewed publications.The optimized ML model accurately predicts the PCE from the experimental parameters with a root mean square error of 1.28%and a Pearson coefficientr of 0.768.Moreover,the factors governing the device performance are ranked by shapley additive explanations(SHAP),among which,A-site cation is crucial to getting highly efficient PSCs.Experiments and density functional theory calculations are employed to validate and help explain the predicting results by the ML model.Our work reveals the feasibility of ML in predicting the device performance from the experimental parameters before experiments,which enables the reverse experimental design toward highly efficient PSCs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474018,61704007,and 61575019)the National Key Research and Development Program of China(Grant No.2017YFB0404501)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.2017RC034)the Shenzhen China Star Optoelectronics Technology Co.,Ltd
文摘Inorganic lead halide perovskite nanocrystals(NCs)with superior photoelectric properties are expected to have excellent performance in many fields.However,the anion exchange changes their features and is unfavorable for their applications in many fields.Hence,impeding anion exchange is important for improving the composition stability of inorganic lead halide perovskite NCs.Herein,CsPb X3(X=Cl,Br)NCs are coated with Cs4PbX6 shell to impede anion exchange and reduce anion mobility.The Cs4PbX6 shell is facily fabricated on CsPbX3 NCs through high temperature injection method.Anion exchange experiments demonstrate that the Cs4 PbX6 shell completely encapsulates CsPbX3 NCs and greatly improves the composition stability of CsPbX3 NCs.Moreover,our work also sheds light on the potential design approaches of various heterostructures to expand the application of CsPbM3(M=Cl,Br,I)NCs.
