Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allo...Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices(solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices(artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.展开更多
The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive...The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive elements.Here,using an advanced crystal structure search approach in conjunction with first-principles calculations,we show that several Xe/He-bearing iron halides are thermodynamically stable in a broad region of P–T phase space below 60 GPa.Our results present a compelling case for sequestration of He and Xe in the early Earth and may suggest their much wider distribution in the present Earth than previously believed.These findings offer insights into key material-based and physical mechanisms for elucidating major geological phenomena.展开更多
We investigate high-pressure phase diagrams of Pr–N compounds by proposing five stable structures(PnmaPr N,Ⅰ4/mmm-PrN_(2),C2/m-PrN_(3),P■-PrN_(4),and R3-PrN_(8))and two metastable structures(P■-PrN_(6)and P■-PrN_...We investigate high-pressure phase diagrams of Pr–N compounds by proposing five stable structures(PnmaPr N,Ⅰ4/mmm-PrN_(2),C2/m-PrN_(3),P■-PrN_(4),and R3-PrN_(8))and two metastable structures(P■-PrN_(6)and P■-PrN_(10)).The P■-PrN_(6)with the N14-ring layer and R3-PrN_(8)with the N18-ring layer can be quenched to ambient conditions.For the P■-PrN_(10),the N_(22)-ring layer structure transfers into infinite chains with the pressure quenched to ambient pressure.Remarkably,a novel polynitrogen h R8-N designed by the excision of Pr atoms from R3-PrN_(8)is obtained and can be quenched to ambient conditions.The N-rich structures of P■-PrN_(6),R3-PrN_(8),c-PrN_(10)and the solid pure nitrogen structure exhibit outstanding properties of energy density and explosive performance.展开更多
We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confin...We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confined LP-N and HLP-N at ambient conditions is revealed.展开更多
The energy dissipation mechanism of energetic materials(EMs) is very important for keeping safety. We choose nitrobenzene as a model of EM and employ transient absorption(TA) spectroscopy and time-resolved coheren...The energy dissipation mechanism of energetic materials(EMs) is very important for keeping safety. We choose nitrobenzene as a model of EM and employ transient absorption(TA) spectroscopy and time-resolved coherent anti-stokes Raman scattering(CARS) to clarify its energy dissipation mechanism. The TA data confirms that the excited nitrobenzene spends about 16 ps finishing the twist intramolecular charge transfer from benzene to nitro group, and dissipates its energy through the rapid vibration relaxation in the initial excited state. And then the dynamics of vibrational modes(VMs) in the ground state of nitrobenzene, which are located at 682 cm^-1(v1), 854 cm^-1(v2), 1006 cm^-1(v3), and 1023 cm^-1(v4),is scanned by CARS. It exhibits that the excess energy of nitrobenzene on the ground state would further dissipate through intramolecular vibrational redistribution based on the vibrational cooling of vi and v2 modes, v1 and v4 modes, and v3 and v4 modes. Moreover, the vibration-vibration coupling depends not only on the energy levels of VMs, but also on the spatial position of chemical bonds relative to the VM.展开更多
Two-dimensional(2D)metal carbides,MXene,present the promising application for the energy storage system.Among the MXene family,Ti_2CT_xas the lightest material,shows its unique electrochemical performance.Herein,Ti_2C...Two-dimensional(2D)metal carbides,MXene,present the promising application for the energy storage system.Among the MXene family,Ti_2CT_xas the lightest material,shows its unique electrochemical performance.Herein,Ti_2CT_xis synthesized by selective etching Al layer from the Ti_2Al C.With the optimized HF treating condition,Ti_2CT_xdisplays high volumetric capacitance and remarkable rate ability.Moreover,the Ti_2CT_x//Ti_2CT_xsymmetric supercapacitor is designed and assembled,which presents capable capacitance,outstanding rate performance and excellent cycling performance.The remarkable electrochemical performance is attributed to its 2D structure and high electronic conductivity.This work demonstrates the potential application of the Ti_2CT_xfor the supercapacitors and provides a template to design highperformance supercapacitors with 2D electrode materials.展开更多
Recently, the high pressure study on the TiO_2 nanomaterials has attracted considerable attention due to the typical crystal structure and the fascinating properties of TiO_2 with nanoscale sizes. In this paper, we br...Recently, the high pressure study on the TiO_2 nanomaterials has attracted considerable attention due to the typical crystal structure and the fascinating properties of TiO_2 with nanoscale sizes. In this paper, we briefly review the recent progress in the high pressure phase transitions of TiO_2 nanomaterials. We discuss the size effects and morphology effects on the high pressure phase transitions of TiO_2 nanomaterials with different particle sizes, morphologies, and microstructures. Several typical pressure-induced structural phase transitions in TiO_2 nanomaterials are presented, including size-dependent phase transition selectivity in nanoparticles, morphology-tuned phase transition in nanowires, nanosheets,and nanoporous materials, and pressure-induced amorphization(PIA) and polyamorphism in ultrafine nanoparticles and TiO_2-B nanoribbons. Various TiO_2 nanostructural materials with high pressure structures are prepared successfully by high pressure treatment of the corresponding crystal nanomaterials, such as amorphous TiO_2 nanoribbons, α-PbO_2-type TiO_2 nanowires, nanosheets, and nanoporous materials. These studies suggest that the high pressure phase transitions of TiO_2 nanomaterials depend on the nanosize, morphology, interface energy, and microstructure. The diversity of high pressure behaviors of TiO_2 nanomaterials provides a new insight into the properties of nanomaterials, and paves a way for preparing new nanomaterials with novel high pressure structures and properties for various applications.展开更多
Pressure is one of the necessary conditions for diamond growth.Exploring the influence of pressure on growth changes in silicon-doped diamonds is of great value for the production of high-quality diamonds.This work re...Pressure is one of the necessary conditions for diamond growth.Exploring the influence of pressure on growth changes in silicon-doped diamonds is of great value for the production of high-quality diamonds.This work reports the morphology,impurity content and crystal quality characteristics of silicon-doped diamond crystals synthesized under different pressures.Fourier transform infrared spectroscopy shows that with the increase of pressure,the nitrogen content in the C-center inside the diamond crystal decreases.X-ray photoelectron spectroscopy test results show the presence of silicon in the diamond crystals synthesized by adding silicon powder.Raman spectroscopy data shows that the increase in pressure in the Fe-Ni-C-Si system shifts the Raman peak of diamonds from 1331.18 cm^(-1)to 1331.25 cm^(-1),resulting in a decrease in internal stress in the crystal.The half-peak width decreased from 5.41 cm^(-1)to 5.26 cm^(-1),and the crystallinity of the silicon-doped diamond crystals improved,resulting in improved quality.This work provides valuable data that can provide a reference for the synthesis of high-quality silicon-doped diamonds.展开更多
High-density Cu2ZnSnS4 (CZTS) materials are prepared via the mechanical alloying and high pressure sintering method using Cu2S, ZnS and SnS2 as the raw materials. The morphological, structural, compositional and ele...High-density Cu2ZnSnS4 (CZTS) materials are prepared via the mechanical alloying and high pressure sintering method using Cu2S, ZnS and SnS2 as the raw materials. The morphological, structural, compositional and electrical properties of the materials are investigated by using x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy, as well as by the Raman scattering and the Hall EFfect measurements. The CZTS synthesized under 5 GPa and 800℃ shows a p-type conductivity, with a resistivity of 9.69 × 10^-2 Ω.cm and a carrier concentration of 1.45 × 10^20 cm-3. It is contributed to by the large grains in the materials reducing the grain boundaries, thus effectively reducing the recombination of the charge carriers.展开更多
Light-to-thermal conversion materials(LTCMs)have been of great interest to researchers due to their impressive energy conversion capacity and wide range of applications in biomedical,desalination,and synergistic catal...Light-to-thermal conversion materials(LTCMs)have been of great interest to researchers due to their impressive energy conversion capacity and wide range of applications in biomedical,desalination,and synergistic catalysis.Given the limited advances in existing materials(metals,semiconductors,π-conjugates),researchers generally adopt the method of constructing complex systems and hybrid structures to optimize performance and achieve multifunctional integration.However,the development of LTCMs is still in its infancy as the physical mechanism of light-to-thermal conversion is unclear.In this review,we proposed design strategies for efficient LTCMs by analyzing the physical process of light-tothermal conversion.First,we analyze the nature of light absorption and heat generation to reveal the physical processes of light-to-thermal conversion.Then,we explain the light-to-thermal conversion mechanisms of metallic,semiconducting andπ-conjugated LCTMs,and propose new material design strategies and performance improvement methods.Finally,we summarize the challenges and prospects of LTCMs in emerging applications such as solar water evaporation and photothermal catalysis.展开更多
Investigating the thermal transport properties of materials is of great importance in the field of earth science and for the development of materials under extremely high temperatures and pressures.However,it is an en...Investigating the thermal transport properties of materials is of great importance in the field of earth science and for the development of materials under extremely high temperatures and pressures.However,it is an enormous challenge to characterize the thermal and physical properties of materials using the diamond anvil cell(DAC)platform.In the present study,a steady-state method is used with a DAC and a combination of thermocouple temperature measurement and numerical analysis is performed to calculate the thermal conductivity of the material.To this end,temperature distributions in the DAC under high pressure are analyzed.We propose a three-dimensional radiative-conductive coupled heat transfer model to simulate the temperature field in the main components of the DAC and calculate in situ thermal conductivity under high-temperature and high-pressure conditions.The proposed model is based on the finite volume method.The obtained results show that heat radiation has a great impact on the temperature field of the DAC,so that ignoring the radiation effect leads to large errors in calculating the heat transport properties of materials.Furthermore,the feasibility of studying the thermal conductivity of different materials is discussed through a numerical model combined with locally measured temperature in the DAC.This article is expected to become a reference for accurate measurement of in situ thermal conductivity in DACs at high-temperature and high-pressure conditions.展开更多
This study presents high pressure phase transitions and equation of states of cerium under pressures up to 51 GPa at room temperature. The angle-dispersive x-ray diffraction experiments are carried out using a high en...This study presents high pressure phase transitions and equation of states of cerium under pressures up to 51 GPa at room temperature. The angle-dispersive x-ray diffraction experiments are carried out using a high energy synchrotron x-ray source. The bulk moduli of high pressure phases of cerium are calculated using the Birch-Mumaghan equation. We discuss and correct several previous controversial conclusions, which are caused by the measurement accuracy or personal explanation. The c/a axial ratio of e-Ce has a maximum value at about 29 GPa, i.e., c/a ≈ 1.690.展开更多
Double perovskite oxide Sr2 Co Fe O6(SCFO) has been obtained using a high-pressure and high-temperature(HPHT)synthesis method. Valence states of Fe and Co and their distributions in SCFO were examined with X-ray p...Double perovskite oxide Sr2 Co Fe O6(SCFO) has been obtained using a high-pressure and high-temperature(HPHT)synthesis method. Valence states of Fe and Co and their distributions in SCFO were examined with X-ray photoelectron spectroscopy. The electric transport behavior of SCFO showed a semiconductor behavior that can be well described by Mott's law for variable-range hopping conduction. The structural stability of SCFO was investigated at pressures up to 31 GPa with no pressure-induced phase transition found. Bulk modulus B0 was determined to be 163(2) GPa by fitting the pressure–volume data to the Birch–Murnaghan equation of state.展开更多
The recent report of superconductivity in nitrogen-doped lutetium hydride(Lu-H-N)at 294 K and 1 GPa brought hope for long-sought-after ambient-condition superconductors.However,the failure of scientists worldwide to i...The recent report of superconductivity in nitrogen-doped lutetium hydride(Lu-H-N)at 294 K and 1 GPa brought hope for long-sought-after ambient-condition superconductors.However,the failure of scientists worldwide to independently reproduce these results has cast intense skepticism on this exciting claim.In this work,using a reliable experimental protocol,we synthesized Lu-H-N while minimizing extrinsic influences and reproduced the sudden change in resistance near room temperature.With quantitative comparison of the temperaturedependent resistance between Lu-H-N and the pure lutetium before reaction,we were able to clarify that the drastic resistance change is most likely caused by a metal-to-poor-conductor transition rather than by superconductivity.Herein,we also briefly discuss other issues recently raised in relation to the Lu-H-N system.展开更多
With the rapid development of artificial intelligence and machine learning(ML)methods,materials science is rapidly entering the era of data-driven materials informatics.ML models serve as the most crucial component,cl...With the rapid development of artificial intelligence and machine learning(ML)methods,materials science is rapidly entering the era of data-driven materials informatics.ML models serve as the most crucial component,closely bridging material structure and material properties.There is a considerable difference in the prediction performance of different ML methods for material systems.Herein,we evaluated three categories(linear,kernel,and nonlinear methods)of models,with twelve ML algorithms commonly used in the materials field.In addition,halide perovskite was chosen as an example to evaluate the fitting performance of different models.We constructed a total dataset of 540 halide perovskites and 72 features,with formation energy and bandgap as target properties.We found that different categories of ML models show similar trends for different target properties.Among them,the difference between the models is enormous for the formation energy,with the coefficient of determination(R2)range 0.69-0.953.The fitting performance between the models is closer for bandgap,with the R^(2)range 0.941-0.997.The nonlinear-ensemble model shows the best fitting performance for both the formation energy and the bandgap.It shows that the nonlinear-ensemble model,constructed by combining multiple weak learners,effectively describes the nonlinear relationship between material features and target property.In addition,the extreme gradient boosting decision tree model shows the most superior results among all the models and searches for two new descriptors that are crucial for formation energy and bandgap.Our work provides useful guidance for the selection of effective machine learning methods in the data-mining studies of specific material systems.展开更多
Diamond, as the hardest known material, has been widely used in industrial applications as abrasives, coatings, and cutting and polishing tools, but it is restricted by several shortcomings, e.g., its low thermal and ...Diamond, as the hardest known material, has been widely used in industrial applications as abrasives, coatings, and cutting and polishing tools, but it is restricted by several shortcomings, e.g., its low thermal and chemical stability. Considerable efforts have been devoted to designing or synthesizing the diamond-like B-C-N-O compounds, which exhibit excellent mechanical property. In this paper, we review the recent theoretical design of diamond-like superhard structures at high pressure. In particular, the recently designed high symmetric phase of low-energy cubic BC3 meets the experimental observation, and clarifies the actual existence of cubic symmetric phase for the compounds formed by B-C-N-O system,besides the classical example of cubic boron nitride.展开更多
A new phase of RhB4is predicted based on first-principles calculations. The new phase belongs to the orthorhombic Pnnm space group, named as o-RhB4, and analysis of the calculated enthalpy shows that o-RhB4belongs to ...A new phase of RhB4is predicted based on first-principles calculations. The new phase belongs to the orthorhombic Pnnm space group, named as o-RhB4, and analysis of the calculated enthalpy shows that o-RhB4belongs to the orthorhombic Pnnm space group. The calculated phonon band structure shows that the orthorhombic Pnnm o-RhB4structure is stable at ambient pressure. We expect that the phase transition can be further confirmed by experiments.展开更多
The high-pressure diagram of V–N compounds is enriched by proposed seven new stable high-pressure phases.The P-1-VN_4with the armchair N-rich structure may be quenched to ambient conditions.The formed N–N covalent b...The high-pressure diagram of V–N compounds is enriched by proposed seven new stable high-pressure phases.The P-1-VN_4with the armchair N-rich structure may be quenched to ambient conditions.The formed N–N covalent bond plays an important role for the structural stability of N-chain.The charge transfer results in a V–N ionic bond interaction,which further improves the stability of N-chain structure.The P-1-VN_4,P4mnc-VN_8,and Immm-VN_(10)with the outstanding detonation properties have potential application in explosive field.展开更多
Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the ...Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the synthesis of Pmn2_(1)-NaN_(5)and Pm-Na_(2)N_(5)through compressing and laser heating pure NaN_(3)at~60 GPa.Upon decompression,the pressureinduced structural transition from Pmn2_(1)-NaN_(5)into Cm-NaN_(5)is observed in the pressure range of 14-23 GPa for the first time.The cyclo-N_(5)^(-)can be traced down to 4.7 GPa at room temperature and recovered to ambient pressure under low temperature condition(up to 160 K).The Pm-Na_(2)N_(5)is suggested to decompose into the P4/mmm-NaN_(2)at 23 GPa,and be stable at ambient conditions.This work provides insight into the high-pressure behaviors of pentazolate compounds and an alternative way to stabilize energetic polynitrogen compounds.展开更多
An ultrafast pump-probe spectroscopy system combined with a cryogenic diamond anvil cell(DAC) instrument is developed to investigate the photo-excitation dynamic properties of condensed materials under low temperature...An ultrafast pump-probe spectroscopy system combined with a cryogenic diamond anvil cell(DAC) instrument is developed to investigate the photo-excitation dynamic properties of condensed materials under low temperature and high pressure(LTHP) conditions.The ultrafast dynamics study is performed on Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi-2212) thin film under LTHP conditions.The superconducting(SC) phase transition has been observed by analyzing the ultrafast dynamics of Bi-2212 as a function of pressure and temperature.Our results suggest that the pump-probe spectroscopy system combined with a cryogenic DAC instrument is an effective method to study the physical mechanism of condensed matter physics at extreme conditions,especially for the SC phase transition.展开更多
基金the National Key Research and Development Program of China (2022YFB3803300)the open research fund of Songshan Lake Materials Laboratory (2021SLABFK02)the National Natural Science Foundation of China (21961160720)。
文摘Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices(solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices(artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.12204280 and 12147135)the Postdoctoral Science Foundation of China(Grant No.2021M691980)+3 种基金Natural Science Foundation of Shandong Province(Grant No.ZR202103010004)the Jilin Province Science and Technology Development Program(Grant No.YDZJ202102CXJD016)the Program for Jilin University Science and Technology Innovative Research Team(2021TD-05)the Program for Jilin University Computational Interdisciplinary Innovative Platform。
文摘The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive elements.Here,using an advanced crystal structure search approach in conjunction with first-principles calculations,we show that several Xe/He-bearing iron halides are thermodynamically stable in a broad region of P–T phase space below 60 GPa.Our results present a compelling case for sequestration of He and Xe in the early Earth and may suggest their much wider distribution in the present Earth than previously believed.These findings offer insights into key material-based and physical mechanisms for elucidating major geological phenomena.
基金financially supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Natural Science Foundation of China(Grant Nos.12174143 and U2032215)。
文摘We investigate high-pressure phase diagrams of Pr–N compounds by proposing five stable structures(PnmaPr N,Ⅰ4/mmm-PrN_(2),C2/m-PrN_(3),P■-PrN_(4),and R3-PrN_(8))and two metastable structures(P■-PrN_(6)and P■-PrN_(10)).The P■-PrN_(6)with the N14-ring layer and R3-PrN_(8)with the N18-ring layer can be quenched to ambient conditions.For the P■-PrN_(10),the N_(22)-ring layer structure transfers into infinite chains with the pressure quenched to ambient pressure.Remarkably,a novel polynitrogen h R8-N designed by the excision of Pr atoms from R3-PrN_(8)is obtained and can be quenched to ambient conditions.The N-rich structures of P■-PrN_(6),R3-PrN_(8),c-PrN_(10)and the solid pure nitrogen structure exhibit outstanding properties of energy density and explosive performance.
基金financially supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant Nos.12174143 and U2032215)the Natural Science Foundation Project of Liaoning Province(Grant No.2022-MS-377)。
文摘We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confined LP-N and HLP-N at ambient conditions is revealed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21573094,11274142,11474131,11574112,and 51502109)the National Found for Fostering Talents of Basic Science,China(Grant No.J1103202)+1 种基金the Science Challenging Program(Grant No.JCKY2016212A501)China Scholarship Council(CSC) during a visit of Ning Sui(Grant No.201706175038) to MPIA is also acknowledged
文摘The energy dissipation mechanism of energetic materials(EMs) is very important for keeping safety. We choose nitrobenzene as a model of EM and employ transient absorption(TA) spectroscopy and time-resolved coherent anti-stokes Raman scattering(CARS) to clarify its energy dissipation mechanism. The TA data confirms that the excited nitrobenzene spends about 16 ps finishing the twist intramolecular charge transfer from benzene to nitro group, and dissipates its energy through the rapid vibration relaxation in the initial excited state. And then the dynamics of vibrational modes(VMs) in the ground state of nitrobenzene, which are located at 682 cm^-1(v1), 854 cm^-1(v2), 1006 cm^-1(v3), and 1023 cm^-1(v4),is scanned by CARS. It exhibits that the excess energy of nitrobenzene on the ground state would further dissipate through intramolecular vibrational redistribution based on the vibrational cooling of vi and v2 modes, v1 and v4 modes, and v3 and v4 modes. Moreover, the vibration-vibration coupling depends not only on the energy levels of VMs, but also on the spatial position of chemical bonds relative to the VM.
基金financially supported by the National Natural Science Foundation of China (51702063)Ministry of Science and Technology of China (No. 2015CB251103)+2 种基金the Science & Technology Department of Jilin Province (No. 20140520093JH)the Open Project of State Key Laboratory of Superhard Materials (Jilin University, No. 201513)the Fundamental Research Funds for the Central Universities (No. GK2100260182)
文摘Two-dimensional(2D)metal carbides,MXene,present the promising application for the energy storage system.Among the MXene family,Ti_2CT_xas the lightest material,shows its unique electrochemical performance.Herein,Ti_2CT_xis synthesized by selective etching Al layer from the Ti_2Al C.With the optimized HF treating condition,Ti_2CT_xdisplays high volumetric capacitance and remarkable rate ability.Moreover,the Ti_2CT_x//Ti_2CT_xsymmetric supercapacitor is designed and assembled,which presents capable capacitance,outstanding rate performance and excellent cycling performance.The remarkable electrochemical performance is attributed to its 2D structure and high electronic conductivity.This work demonstrates the potential application of the Ti_2CT_xfor the supercapacitors and provides a template to design highperformance supercapacitors with 2D electrode materials.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB808200)the National Natural Science Foundation of China(Grant Nos.11374120,11004075,10979001,51025206,51032001,and 21073071)the Cheung Kong Scholars Programme of China
文摘Recently, the high pressure study on the TiO_2 nanomaterials has attracted considerable attention due to the typical crystal structure and the fascinating properties of TiO_2 with nanoscale sizes. In this paper, we briefly review the recent progress in the high pressure phase transitions of TiO_2 nanomaterials. We discuss the size effects and morphology effects on the high pressure phase transitions of TiO_2 nanomaterials with different particle sizes, morphologies, and microstructures. Several typical pressure-induced structural phase transitions in TiO_2 nanomaterials are presented, including size-dependent phase transition selectivity in nanoparticles, morphology-tuned phase transition in nanowires, nanosheets,and nanoporous materials, and pressure-induced amorphization(PIA) and polyamorphism in ultrafine nanoparticles and TiO_2-B nanoribbons. Various TiO_2 nanostructural materials with high pressure structures are prepared successfully by high pressure treatment of the corresponding crystal nanomaterials, such as amorphous TiO_2 nanoribbons, α-PbO_2-type TiO_2 nanowires, nanosheets, and nanoporous materials. These studies suggest that the high pressure phase transitions of TiO_2 nanomaterials depend on the nanosize, morphology, interface energy, and microstructure. The diversity of high pressure behaviors of TiO_2 nanomaterials provides a new insight into the properties of nanomaterials, and paves a way for preparing new nanomaterials with novel high pressure structures and properties for various applications.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.51872112 and 51772120)。
文摘Pressure is one of the necessary conditions for diamond growth.Exploring the influence of pressure on growth changes in silicon-doped diamonds is of great value for the production of high-quality diamonds.This work reports the morphology,impurity content and crystal quality characteristics of silicon-doped diamond crystals synthesized under different pressures.Fourier transform infrared spectroscopy shows that with the increase of pressure,the nitrogen content in the C-center inside the diamond crystal decreases.X-ray photoelectron spectroscopy test results show the presence of silicon in the diamond crystals synthesized by adding silicon powder.Raman spectroscopy data shows that the increase in pressure in the Fe-Ni-C-Si system shifts the Raman peak of diamonds from 1331.18 cm^(-1)to 1331.25 cm^(-1),resulting in a decrease in internal stress in the crystal.The half-peak width decreased from 5.41 cm^(-1)to 5.26 cm^(-1),and the crystallinity of the silicon-doped diamond crystals improved,resulting in improved quality.This work provides valuable data that can provide a reference for the synthesis of high-quality silicon-doped diamonds.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10874178,11074093,61205038 and 11274135the National Found for Fostering Talents of Basic Science under Grant No J1103202+2 种基金the Ph.D.Programs Foundation of Ministry of Education of China under Grant No 20120061120011the Open Project of State Key Laboratory of Superhard Materials of Jilin Universitythe State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University
文摘High-density Cu2ZnSnS4 (CZTS) materials are prepared via the mechanical alloying and high pressure sintering method using Cu2S, ZnS and SnS2 as the raw materials. The morphological, structural, compositional and electrical properties of the materials are investigated by using x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy, as well as by the Raman scattering and the Hall EFfect measurements. The CZTS synthesized under 5 GPa and 800℃ shows a p-type conductivity, with a resistivity of 9.69 × 10^-2 Ω.cm and a carrier concentration of 1.45 × 10^20 cm-3. It is contributed to by the large grains in the materials reducing the grain boundaries, thus effectively reducing the recombination of the charge carriers.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.52272153,52032004)the KLOMT Key Laboratory Open Project(2022KLOMT02-05)。
文摘Light-to-thermal conversion materials(LTCMs)have been of great interest to researchers due to their impressive energy conversion capacity and wide range of applications in biomedical,desalination,and synergistic catalysis.Given the limited advances in existing materials(metals,semiconductors,π-conjugates),researchers generally adopt the method of constructing complex systems and hybrid structures to optimize performance and achieve multifunctional integration.However,the development of LTCMs is still in its infancy as the physical mechanism of light-to-thermal conversion is unclear.In this review,we proposed design strategies for efficient LTCMs by analyzing the physical process of light-tothermal conversion.First,we analyze the nature of light absorption and heat generation to reveal the physical processes of light-to-thermal conversion.Then,we explain the light-to-thermal conversion mechanisms of metallic,semiconducting andπ-conjugated LCTMs,and propose new material design strategies and performance improvement methods.Finally,we summarize the challenges and prospects of LTCMs in emerging applications such as solar water evaporation and photothermal catalysis.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFA0702700)the National Natural Science Foundation of China(Grant Nos.11674404 and 11774126)。
文摘Investigating the thermal transport properties of materials is of great importance in the field of earth science and for the development of materials under extremely high temperatures and pressures.However,it is an enormous challenge to characterize the thermal and physical properties of materials using the diamond anvil cell(DAC)platform.In the present study,a steady-state method is used with a DAC and a combination of thermocouple temperature measurement and numerical analysis is performed to calculate the thermal conductivity of the material.To this end,temperature distributions in the DAC under high pressure are analyzed.We propose a three-dimensional radiative-conductive coupled heat transfer model to simulate the temperature field in the main components of the DAC and calculate in situ thermal conductivity under high-temperature and high-pressure conditions.The proposed model is based on the finite volume method.The obtained results show that heat radiation has a great impact on the temperature field of the DAC,so that ignoring the radiation effect leads to large errors in calculating the heat transport properties of materials.Furthermore,the feasibility of studying the thermal conductivity of different materials is discussed through a numerical model combined with locally measured temperature in the DAC.This article is expected to become a reference for accurate measurement of in situ thermal conductivity in DACs at high-temperature and high-pressure conditions.
基金supported by the National Natural Science Foundation of China(Grant No.NSAF.U1330115)the National Major Scientific Instrument and Equipment Development Project of China(Grant No.2012YQ130234)
文摘This study presents high pressure phase transitions and equation of states of cerium under pressures up to 51 GPa at room temperature. The angle-dispersive x-ray diffraction experiments are carried out using a high energy synchrotron x-ray source. The bulk moduli of high pressure phases of cerium are calculated using the Birch-Mumaghan equation. We discuss and correct several previous controversial conclusions, which are caused by the measurement accuracy or personal explanation. The c/a axial ratio of e-Ce has a maximum value at about 29 GPa, i.e., c/a ≈ 1.690.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51172194 and 51172091)the Program for New Century Excellent Talents in University,China(Grant No.NCET-12-0240)Jilin Province Science and Technology Development Program,China(Grant No.20130101023JC)
文摘Double perovskite oxide Sr2 Co Fe O6(SCFO) has been obtained using a high-pressure and high-temperature(HPHT)synthesis method. Valence states of Fe and Co and their distributions in SCFO were examined with X-ray photoelectron spectroscopy. The electric transport behavior of SCFO showed a semiconductor behavior that can be well described by Mott's law for variable-range hopping conduction. The structural stability of SCFO was investigated at pressures up to 31 GPa with no pressure-induced phase transition found. Bulk modulus B0 was determined to be 163(2) GPa by fitting the pressure–volume data to the Birch–Murnaghan equation of state.
文摘The recent report of superconductivity in nitrogen-doped lutetium hydride(Lu-H-N)at 294 K and 1 GPa brought hope for long-sought-after ambient-condition superconductors.However,the failure of scientists worldwide to independently reproduce these results has cast intense skepticism on this exciting claim.In this work,using a reliable experimental protocol,we synthesized Lu-H-N while minimizing extrinsic influences and reproduced the sudden change in resistance near room temperature.With quantitative comparison of the temperaturedependent resistance between Lu-H-N and the pure lutetium before reaction,we were able to clarify that the drastic resistance change is most likely caused by a metal-to-poor-conductor transition rather than by superconductivity.Herein,we also briefly discuss other issues recently raised in relation to the Lu-H-N system.
基金supported by the National Natural Science Foundation of China(Grants Nos.62125402 and 92061113)。
文摘With the rapid development of artificial intelligence and machine learning(ML)methods,materials science is rapidly entering the era of data-driven materials informatics.ML models serve as the most crucial component,closely bridging material structure and material properties.There is a considerable difference in the prediction performance of different ML methods for material systems.Herein,we evaluated three categories(linear,kernel,and nonlinear methods)of models,with twelve ML algorithms commonly used in the materials field.In addition,halide perovskite was chosen as an example to evaluate the fitting performance of different models.We constructed a total dataset of 540 halide perovskites and 72 features,with formation energy and bandgap as target properties.We found that different categories of ML models show similar trends for different target properties.Among them,the difference between the models is enormous for the formation energy,with the coefficient of determination(R2)range 0.69-0.953.The fitting performance between the models is closer for bandgap,with the R^(2)range 0.941-0.997.The nonlinear-ensemble model shows the best fitting performance for both the formation energy and the bandgap.It shows that the nonlinear-ensemble model,constructed by combining multiple weak learners,effectively describes the nonlinear relationship between material features and target property.In addition,the extreme gradient boosting decision tree model shows the most superior results among all the models and searches for two new descriptors that are crucial for formation energy and bandgap.Our work provides useful guidance for the selection of effective machine learning methods in the data-mining studies of specific material systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51202084,11474125,and 51372095)
文摘Diamond, as the hardest known material, has been widely used in industrial applications as abrasives, coatings, and cutting and polishing tools, but it is restricted by several shortcomings, e.g., its low thermal and chemical stability. Considerable efforts have been devoted to designing or synthesizing the diamond-like B-C-N-O compounds, which exhibit excellent mechanical property. In this paper, we review the recent theoretical design of diamond-like superhard structures at high pressure. In particular, the recently designed high symmetric phase of low-energy cubic BC3 meets the experimental observation, and clarifies the actual existence of cubic symmetric phase for the compounds formed by B-C-N-O system,besides the classical example of cubic boron nitride.
基金Supported by the Natural Science Foundation of Shandong Province under Grant Nos ZR2016AP02,ZR2016FM38 and ZR2016EMP01the Innovation Project of Ludong University under Grant No LB2016013+1 种基金the Open Project of State Key Laboratory of Superhard Materials of Jilin University under Grant No 201605the National Natural Science Foundation of China under Grant Nos 11704170 and 61705097
文摘A new phase of RhB4is predicted based on first-principles calculations. The new phase belongs to the orthorhombic Pnnm space group, named as o-RhB4, and analysis of the calculated enthalpy shows that o-RhB4belongs to the orthorhombic Pnnm space group. The calculated phonon band structure shows that the orthorhombic Pnnm o-RhB4structure is stable at ambient pressure. We expect that the phase transition can be further confirmed by experiments.
文摘The high-pressure diagram of V–N compounds is enriched by proposed seven new stable high-pressure phases.The P-1-VN_4with the armchair N-rich structure may be quenched to ambient conditions.The formed N–N covalent bond plays an important role for the structural stability of N-chain.The charge transfer results in a V–N ionic bond interaction,which further improves the stability of N-chain structure.The P-1-VN_4,P4mnc-VN_8,and Immm-VN_(10)with the outstanding detonation properties have potential application in explosive field.
基金Project supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Nat-ural Science Foundation of China(Grant Nos.12174143,11634004,11847094,and 11804384)JLU Science and Technology Innovative Research Team(Grant No.2017TD-01)。
文摘Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the synthesis of Pmn2_(1)-NaN_(5)and Pm-Na_(2)N_(5)through compressing and laser heating pure NaN_(3)at~60 GPa.Upon decompression,the pressureinduced structural transition from Pmn2_(1)-NaN_(5)into Cm-NaN_(5)is observed in the pressure range of 14-23 GPa for the first time.The cyclo-N_(5)^(-)can be traced down to 4.7 GPa at room temperature and recovered to ambient pressure under low temperature condition(up to 160 K).The Pm-Na_(2)N_(5)is suggested to decompose into the P4/mmm-NaN_(2)at 23 GPa,and be stable at ambient conditions.This work provides insight into the high-pressure behaviors of pentazolate compounds and an alternative way to stabilize energetic polynitrogen compounds.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12274168 and 12074141)。
文摘An ultrafast pump-probe spectroscopy system combined with a cryogenic diamond anvil cell(DAC) instrument is developed to investigate the photo-excitation dynamic properties of condensed materials under low temperature and high pressure(LTHP) conditions.The ultrafast dynamics study is performed on Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi-2212) thin film under LTHP conditions.The superconducting(SC) phase transition has been observed by analyzing the ultrafast dynamics of Bi-2212 as a function of pressure and temperature.Our results suggest that the pump-probe spectroscopy system combined with a cryogenic DAC instrument is an effective method to study the physical mechanism of condensed matter physics at extreme conditions,especially for the SC phase transition.