Bulk metallic glasses with up to 72 mm critical section thickness have been obtained by conventional casting techniques and the properties of these materials, particularly the mechanical and magnetic properties have b...Bulk metallic glasses with up to 72 mm critical section thickness have been obtained by conventional casting techniques and the properties of these materials, particularly the mechanical and magnetic properties have been studied. These materials have been demonstrated to have novel properties which are fundamentally different from their crystalline counterparts. The recent status of research and development in formation, structure and properties of bulk metallic glasses is reviewed. The techniques to produce such bulk glasses are summarized and the glass forming ability and the critical cooling rate of these materials are discussed. Further consideration of the development and application of this new class of materiaIs will be proposed.展开更多
Bulk metallic glass Zr_52.5Ni_14.6Al_10Cu_17.9Ti_5 was prepared by melt injection casting method. Its glass transition and crystallization temperatures were determined by differential scanning calorimetry (DSC) to be ...Bulk metallic glass Zr_52.5Ni_14.6Al_10Cu_17.9Ti_5 was prepared by melt injection casting method. Its glass transition and crystallization temperatures were determined by differential scanning calorimetry (DSC) to be 631 K and 710 K respectively. By analysis of X-ray diffractometry (XRD) and transmission electron microscopy (TEM ), the predominant crystallized phase of Zr_2Ni0.67O0.33 distributed on glass state matrix was detected after annealing at 673 K for 600 s. The transformation to Zr_2Ni_0.67O_0.33 and a small amount of ZrAl and Zr_2Cu took place after annealing for 600 s at temperature from 703 K to 723 K. With increasing annealing temperature from 753 K to 823 K, the amounts of ZrAl and Zr_2Cu increased, but the size of the crystals did not significantly change. The transformation to Zr_2Ni_0.67O_0.33 is interface-controlled, but is diffusion-controlled to Zr_2Cu and ZrAl. With increasing annealing temperature up to 200 K above T_x, the nanometer grains became very fine because of the increase of nucleation rate for Zr_2Cu and ZrAl.展开更多
The structures of the bulk amorphous Zr41Ti14Cu12.5Nil0.0Be22.5 alloy have been analyzed in solid, supercooled liquid and liquid with X-ray diffraction. The first coordination sphere radii and the first coordination n...The structures of the bulk amorphous Zr41Ti14Cu12.5Nil0.0Be22.5 alloy have been analyzed in solid, supercooled liquid and liquid with X-ray diffraction. The first coordination sphere radii and the first coordination numbers are 0.312 um, 11.2 in solid state.10.932 nm, 10.932 in supercooled liquid region and 0.305 urn, 11.296 in liquid state. The structures are the same in different states. But it shows some tendency to crystallizing that the first coordination sphere radius and the first coordination number drop in supercooled liquid region.展开更多
By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the d...By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.展开更多
The copper-cerium catalysts demonstrate high efficiency in CO_(2)reduction reactions(CO_(2)RR).However,the mechanism governing the formation of C_(2)H_(4)and CH_(4)by regulating Cu bulk phase structure at the copper-c...The copper-cerium catalysts demonstrate high efficiency in CO_(2)reduction reactions(CO_(2)RR).However,the mechanism governing the formation of C_(2)H_(4)and CH_(4)by regulating Cu bulk phase structure at the copper-cerium interface remains unclear due to the instability and dynamic evaluations of copper species.Herein,we synthesized CeO_(2)-CuO containing solely Cu^(2+)species and CeO_(2)-Cu featuring predominantly metallic Cu species at the interface,which exhibit stable structures under various potentials,offering ideal models for in-depth mechanistic studies.The C_(2)H_(4)is the main product over the CeO_(2)-CuO catalyst,exhibiting a Faradaic efficiency(FE)of 42.3%±1.4%,while CH_(4)is the primary product over the CeO_(2)-Cu catalyst,with a FE of 32.4%±1.3%.These results demonstrate that regulating bulk phase Cu structure at the copper-cerium interface influences the selectivity of hydrocarbon products.The operando ATR-SEIRAS finds that CeO_(2)-CuO surfaces with single linear*CO adsorption are advantageous for synthesizing*COCO,whereas bridge-bonded*CO adsorption promoted*CHO formation.Furthermore,DFT simulations demonstrate that the energy barrier of CO-CO coupling(C_(2)H_(4)pathway)at the CeO_(2)-CuO interface decreases as compared to the CeO_(2)-Cu catalyst,thus indicating a facilitated conversion of the CO_(2)to C_(2)H_(4).This research deepens the mechanistic understanding of the copper-cerium system during CO_(2)RR and effectively formulates a strategy for developing high-selectivity catalysts.展开更多
Several lithium-ion batteries of 18650-type were assembled with pristine or Al2O3-coated LiNi0.4Co0.2Mn0.4O2（NCM） as cathode material and mesocarbon microbeads（MCMB） as anode material.The cycling performance of th...Several lithium-ion batteries of 18650-type were assembled with pristine or Al2O3-coated LiNi0.4Co0.2Mn0.4O2（NCM） as cathode material and mesocarbon microbeads（MCMB） as anode material.The cycling performance of the batteries was examined under 25 °C at a 2C rate within a potential range of 2.75―4.20 V.The changes of the crystal structure,the lattice parameter,the mean crystallite size,and the mean micro-strain of pristine NCM and Al2O3-coated NCM during the charge-discharge cycling were determined by X-ray diffraction（XRD）.The results indicate that the bulk structure of Al2O3-coated NCM is more stable than that of pristine NCM,which leads to the better cycling performance of Al2O3-coated NCM compared to that of pristine NCM.展开更多
Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network act...Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer deposition.This optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture capability.This approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.展开更多
Under the synergistic effect of molecular design and devices engineering, small molecular organic solar cells have presented an unstoppable tendency for rapid development with putting forward donor- acceptor （D-A） s...Under the synergistic effect of molecular design and devices engineering, small molecular organic solar cells have presented an unstoppable tendency for rapid development with putting forward donor- acceptor （D-A） structures. Up to now, the highest power conversion efficiency of small molecules has exceeded 11%, comparable to that of polymers. In this review, we summarize the high performance small molecule donors in various classes of typical donor-acceptor （D-A） structures and discuss their relationships briefly.展开更多
The structural, electronic and elastic properties of YCu compound in the B2 （CsCl） phase were investigated using the density functional theory （DFT） within the generalized gradient approximation （GGA）. The elect...The structural, electronic and elastic properties of YCu compound in the B2 （CsCl） phase were investigated using the density functional theory （DFT） within the generalized gradient approximation （GGA）. The electronic density of states （DOS） obtained in this way accorded weU with the results of a recent study utilizing the full-potential linearized augmented plane wave （FLAPW） method. We also found that the density of d-states at the Fermi energy was low. The calculated equilibrium properties such as lattice constant, bulk modulus and its first derivative, and the elastic constants were in good agreement with experimental and theoretical results.展开更多
The semi-empirical pseudopotential method(SEPM)has been widely applied to provide computational insights into the electronic structure,photophysics,and charge carrier dynamics of nanoscale materials.We present“DeepPs...The semi-empirical pseudopotential method(SEPM)has been widely applied to provide computational insights into the electronic structure,photophysics,and charge carrier dynamics of nanoscale materials.We present“DeepPseudopot”,a machine-learned atomistic pseudopotential model that extends the SEPM framework by combining a flexible neural network representation of the local pseudopotential with parameterized non-local and spin-orbit coupling terms.Trained on bulk quasiparticle band structures and deformation potentials from GW calculations,the model captures many-body and relativistic effects with very high accuracy across diverse semiconducting materials,as illustrated for silicon and group III-V semiconductors.DeepPseudopot’s accuracy,efficiency,and transferability make it well-suited for data-driven in silico design and discovery of novel optoelectronic nanomaterials.展开更多
文摘Bulk metallic glasses with up to 72 mm critical section thickness have been obtained by conventional casting techniques and the properties of these materials, particularly the mechanical and magnetic properties have been studied. These materials have been demonstrated to have novel properties which are fundamentally different from their crystalline counterparts. The recent status of research and development in formation, structure and properties of bulk metallic glasses is reviewed. The techniques to produce such bulk glasses are summarized and the glass forming ability and the critical cooling rate of these materials are discussed. Further consideration of the development and application of this new class of materiaIs will be proposed.
文摘Bulk metallic glass Zr_52.5Ni_14.6Al_10Cu_17.9Ti_5 was prepared by melt injection casting method. Its glass transition and crystallization temperatures were determined by differential scanning calorimetry (DSC) to be 631 K and 710 K respectively. By analysis of X-ray diffractometry (XRD) and transmission electron microscopy (TEM ), the predominant crystallized phase of Zr_2Ni0.67O0.33 distributed on glass state matrix was detected after annealing at 673 K for 600 s. The transformation to Zr_2Ni_0.67O_0.33 and a small amount of ZrAl and Zr_2Cu took place after annealing for 600 s at temperature from 703 K to 723 K. With increasing annealing temperature from 753 K to 823 K, the amounts of ZrAl and Zr_2Cu increased, but the size of the crystals did not significantly change. The transformation to Zr_2Ni_0.67O_0.33 is interface-controlled, but is diffusion-controlled to Zr_2Cu and ZrAl. With increasing annealing temperature up to 200 K above T_x, the nanometer grains became very fine because of the increase of nucleation rate for Zr_2Cu and ZrAl.
文摘The structures of the bulk amorphous Zr41Ti14Cu12.5Nil0.0Be22.5 alloy have been analyzed in solid, supercooled liquid and liquid with X-ray diffraction. The first coordination sphere radii and the first coordination numbers are 0.312 um, 11.2 in solid state.10.932 nm, 10.932 in supercooled liquid region and 0.305 urn, 11.296 in liquid state. The structures are the same in different states. But it shows some tendency to crystallizing that the first coordination sphere radius and the first coordination number drop in supercooled liquid region.
基金Supported by the National Basic Research Program of China(973 Program)under Grant Nos 2011CBA00106 and2012CB927400the National Natural Science Foundation of China under Grant Nos 11274332 and 11227902Helmholtz Association through the Virtual Institute for Topological Insulators(VITI).M.Y.Li and D.W.Shen are also supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB04040300
文摘By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.
基金supported financially by the National Natural Science Foundation of China (22302222, 22072172)the Postdoctoral Science Foundation (2024T170965, 2023M743641)+5 种基金the Youth Innovation Promotion Association CAS (Y2021056)Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy (YLU-DNL Fund 2022007)the Major Science and Technology Projects of Shanxi Province (202005D121002)the Special Fund for Science and Technology Innovation Teams of Shanxi Province (202304051001007)the Science and Technology Department of Shanxi Province (202303021222409)the Shanxi Provincial Department of Human and Social Resources Security’s Doctor Introduction Program (2024SHB001)
文摘The copper-cerium catalysts demonstrate high efficiency in CO_(2)reduction reactions(CO_(2)RR).However,the mechanism governing the formation of C_(2)H_(4)and CH_(4)by regulating Cu bulk phase structure at the copper-cerium interface remains unclear due to the instability and dynamic evaluations of copper species.Herein,we synthesized CeO_(2)-CuO containing solely Cu^(2+)species and CeO_(2)-Cu featuring predominantly metallic Cu species at the interface,which exhibit stable structures under various potentials,offering ideal models for in-depth mechanistic studies.The C_(2)H_(4)is the main product over the CeO_(2)-CuO catalyst,exhibiting a Faradaic efficiency(FE)of 42.3%±1.4%,while CH_(4)is the primary product over the CeO_(2)-Cu catalyst,with a FE of 32.4%±1.3%.These results demonstrate that regulating bulk phase Cu structure at the copper-cerium interface influences the selectivity of hydrocarbon products.The operando ATR-SEIRAS finds that CeO_(2)-CuO surfaces with single linear*CO adsorption are advantageous for synthesizing*COCO,whereas bridge-bonded*CO adsorption promoted*CHO formation.Furthermore,DFT simulations demonstrate that the energy barrier of CO-CO coupling(C_(2)H_(4)pathway)at the CeO_(2)-CuO interface decreases as compared to the CeO_(2)-Cu catalyst,thus indicating a facilitated conversion of the CO_(2)to C_(2)H_(4).This research deepens the mechanistic understanding of the copper-cerium system during CO_(2)RR and effectively formulates a strategy for developing high-selectivity catalysts.
基金Supported by the Project of Shanghai Committee of Science and Technology,China(Nos.1052nm00100,09ZR1437600)
文摘Several lithium-ion batteries of 18650-type were assembled with pristine or Al2O3-coated LiNi0.4Co0.2Mn0.4O2（NCM） as cathode material and mesocarbon microbeads（MCMB） as anode material.The cycling performance of the batteries was examined under 25 °C at a 2C rate within a potential range of 2.75―4.20 V.The changes of the crystal structure,the lattice parameter,the mean crystallite size,and the mean micro-strain of pristine NCM and Al2O3-coated NCM during the charge-discharge cycling were determined by X-ray diffraction（XRD）.The results indicate that the bulk structure of Al2O3-coated NCM is more stable than that of pristine NCM,which leads to the better cycling performance of Al2O3-coated NCM compared to that of pristine NCM.
基金Technology Development Program of Jilin Province(YDZJ202201ZYTS640)the National Key Research and Development Program of China(2022YFB4200400)funded by MOST+4 种基金the National Natural Science Foundation of China(52172048 and 52103221)Shandong Provincial Natural Science Foundation(ZR2021QB024 and ZR2021ZD06)Guangdong Basic and Applied Basic Research Foundation(2023A1515012323,2023A1515010943,and 2024A1515010023)the Qingdao New Energy Shandong Laboratory open Project(QNESL OP 202309)the Fundamental Research Funds of Shandong University.
文摘Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer deposition.This optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture capability.This approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.
基金supported by the National Natural Science Foundation of China (Nos. 21474022, 51603051)Youth Innovation Promotion Association CAS and Beijing Nova Program (No. Z171100001117062)the Chinese Academy of Sciences
文摘Under the synergistic effect of molecular design and devices engineering, small molecular organic solar cells have presented an unstoppable tendency for rapid development with putting forward donor- acceptor （D-A） structures. Up to now, the highest power conversion efficiency of small molecules has exceeded 11%, comparable to that of polymers. In this review, we summarize the high performance small molecule donors in various classes of typical donor-acceptor （D-A） structures and discuss their relationships briefly.
基金supported by Gazi University Research Project Unit (05/2007/18)Hacettepe University (0701602005)
文摘The structural, electronic and elastic properties of YCu compound in the B2 （CsCl） phase were investigated using the density functional theory （DFT） within the generalized gradient approximation （GGA）. The electronic density of states （DOS） obtained in this way accorded weU with the results of a recent study utilizing the full-potential linearized augmented plane wave （FLAPW） method. We also found that the density of d-states at the Fermi energy was low. The calculated equilibrium properties such as lattice constant, bulk modulus and its first derivative, and the elastic constants were in good agreement with experimental and theoretical results.
基金supported by the National Science Foundation Division of Chemistry, under the Chemical Theory, Models and Computational Methods (CTMC) program, grant number CHE-2449564Methods used to describe the vibronic properties of NCs were provided by the center on “Traversing the death valley separating short and long times in non-equilibrium quantum dynamical simulations of real materials”, which is funded by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research and Office of Basic Energy Sciences, Scientific Discovery through Advanced Computing (SciDAC) program, under Award No. DE-SC0022088+2 种基金Measured optical properties of III-V NCs were supported by the National Science Foundation Science and Technology Center (STC) for Integration of Modern Optoelectronic Materials on Demand (IMOD) under Cooperative Agreement No. DMR-2019444This research used resources of the National Energy Research Scientific Computing Center (NERSC)a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using NERSC award BES-ERCAP0032503.
文摘The semi-empirical pseudopotential method(SEPM)has been widely applied to provide computational insights into the electronic structure,photophysics,and charge carrier dynamics of nanoscale materials.We present“DeepPseudopot”,a machine-learned atomistic pseudopotential model that extends the SEPM framework by combining a flexible neural network representation of the local pseudopotential with parameterized non-local and spin-orbit coupling terms.Trained on bulk quasiparticle band structures and deformation potentials from GW calculations,the model captures many-body and relativistic effects with very high accuracy across diverse semiconducting materials,as illustrated for silicon and group III-V semiconductors.DeepPseudopot’s accuracy,efficiency,and transferability make it well-suited for data-driven in silico design and discovery of novel optoelectronic nanomaterials.
