Rational design of the components and microstructure is regarded as an efficacious strategy for the high-performance electromagnetic wave absorbing(EMWA)materials.Herein,the CoTe_(2)@MoS_(2)nanocomposites with CoTe_(2...Rational design of the components and microstructure is regarded as an efficacious strategy for the high-performance electromagnetic wave absorbing(EMWA)materials.Herein,the CoTe_(2)@MoS_(2)nanocomposites with CoTe_(2)nanorods and MoS_(2)nanosheets were synthesized via a hydrothermal method.The microstructure and composition of the samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The CoTe_(2)@MoS_(2)composite was composed of stacked CoTe_(2)as the core and intertwined MoS_(2)nanosheets as the shell.The electromagnetic parameters of the CoTe_(2)@MoS_(2)composites were investigated by vector network analyzer(VNA).The EMWA property of the composite showed a trend of first increasing and then decreasing with the increasing content of MoS_(2).When the mass ratio of MoS_(2)and CoTe_(2)was 1:1,the CoTe_(2)@MoS_(2)composite exhibited the minimum reflection loss value of-68.10 dB at 4.71 GHz,and the effective absorption bandwidth value might reach 4.64 GHz(13.08-17.72 GHz)at a matching thickness of 1.60 mm with filler loading of 50 wt.%.The extraordinary EMWA property was attributed to the optimized impedance matching,multiple scattering and reflections,dipole polarization,conductive loss,and interfacial polarization.Therefore,the present approach to the design of microstructure and interface engineering offers a crucial way to construct high-performance EMW absorbers.展开更多
Owning various crystal structures and high theoretical capacity,metal tellurides are emerging as promising electrode materials for high-performance metal-ion batteries(MBs).Since metal telluride-based MBs are quite ne...Owning various crystal structures and high theoretical capacity,metal tellurides are emerging as promising electrode materials for high-performance metal-ion batteries(MBs).Since metal telluride-based MBs are quite new,fundamental issues raise regarding the energy storage mechanism and other aspects affecting electrochemical performance.Severe volume expansion,low intrinsic conductivity and slow ion diffusion kinetics jeopardize the performance of metal tellurides,so that rational design and engineering are crucial to circumvent these disadvantages.Herein,this review provides an in-depth discussion of recent investigations and progresses of metal tellurides,beginning with a critical discussion on the energy storage mechanisms of metal tellurides in various MBs.In the following,recent design and engineering strategies of metal tellurides,including morphology engineering,compositing,defect engineering and heterostructure construction,for high-performance MBs are summarized.The primary focus is to present a comprehensive understanding of the structural evolution based on the mechanism and corresponding effects of dimension control,composition,electron configuration and structural complexity on the electrochemical performance.In closing,outlooks and prospects for future development of metal tellurides are proposed.This work also highlights the promising directions of design and engineering strategies of metal tellurides with high performance and low cost.展开更多
Lithium-sulfur(Li-S)batteries are broadly regarded as one of the most promising energy storage systems owing to their high-energy and low-cost features.Nevertheless,their practical implementation is plagued by the not...Lithium-sulfur(Li-S)batteries are broadly regarded as one of the most promising energy storage systems owing to their high-energy and low-cost features.Nevertheless,their practical implementation is plagued by the notorious polysulfide shuttling and sluggish reaction kinetics.Transition metal telluride has emerged as a promising electrocatalyst to expedite sulfur redox kinetics,even though its controllable and precise fabrication remains quite elusive.Herein,we propose the employment of a chemical vapor deposition approach to achieve in situ growth of Co-doped NiTe_(2)(Co-NiTe_(2))on vertically oriented graphene coated carbon cloth(VG/CC)substrate,in the pursuit of high-performance sulfur host material(Co-NiTe_(2)@VG/CC)in Li-S realms.Electrokinetic analysis and operando Raman spectroscopy characterization reveal the effective regulation capability of Co-NiTe_(2)@VG/CC with respect to polysulfide capture/conversion and Li2S decomposition.As a result,the Al-currentcollector-free Co-NiTe_(2)@VG/CC-based cathodes with typical sulfur loading exhibit outstanding cycling stability(93.8% capacity retention over 100 cycles at 0.5 C).Moreover,an areal capacity of 4.27 mAh cm^(-2) at 0.2 C can be harvested even at an elevated sulfur loading of 7.2 mg cm^(-2).展开更多
Exploiting high-rate anode materials with fast K+diffusion is intriguing for the development of advanced potassium-ion batteries(KIBs)but remains unrealized.Here,heterostructure engineering is proposed to construct th...Exploiting high-rate anode materials with fast K+diffusion is intriguing for the development of advanced potassium-ion batteries(KIBs)but remains unrealized.Here,heterostructure engineering is proposed to construct the dual transition metal tellurides(CoTe_(2)/ZnTe),which are anchored onto two-dimensional(2D)Ti_(3)C_(2)T_(x)MXene nanosheets.Various theoretical modeling and experimental findings reveal that heterostructure engineering can regulate the electronic structures of CoTe_(2)/ZnTe interfaces,improving K+diffusion and adsorption.In addition,the different work functions between CoTe_(2)/ZnTe induce a robust built-in electric field at the CoTe_(2)/ZnTe interface,providing a strong driving force to facilitate charge transport.Moreover,the conductive and elastic Ti_(3)C_(2)T_(x)can effectively promote electrode conductivity and alleviate the volume change of CoTe_(2)/ZnTe heterostructures upon cycling.Owing to these merits,the resulting CoTe_(2)/ZnTe/Ti_(3)C_(2)T_(x)(CZT)exhibit excellent rate capability(137.0 mAh g^(-1)at 10 A g^(-1))and cycling stability(175.3 mAh g^(-1)after 4000 cycles at 3.0 A g^(-1),with a high capacity retention of 89.4%).More impressively,the CZT-based full cells demonstrate high energy density(220.2 Wh kg^(-1))and power density(837.2 W kg^(-1)).This work provides a general and effective strategy by integrating heterostructure engineering and 2D material nanocompositing for designing advanced high-rate anode materials for next-generation KIBs.展开更多
With the dramatic developments of renewable and environmental-friendly electrochemical energy conversion systems,there is an urgent need to fabricate durable and efficient electrocatalysts to address the limitation of...With the dramatic developments of renewable and environmental-friendly electrochemical energy conversion systems,there is an urgent need to fabricate durable and efficient electrocatalysts to address the limitation of high overpotentials exceeding thermodynamic requirements to facilitate practical applications.Recently,tellurium-based nanomaterials(Te NMs)with unique chemical,electronic,and topological properties,including Te-derived nanostructures and transition metal tellurides(TMTs),have emerged as one of the most promising electrocatalytic materials.In the absence of comprehensive and guiding reviews,this review comprehensively summarizes the main advances in designing emerging Te NMs for electrocatalysis.First,the engineering strategies and principles of Te NMs to enhance their electrocatalytic activity and stability from the nanostructures to the catalytic atoms are discussed in detail,especially on the chemical/physical/multiplex templating strategies,heteroatom doping,vacancy/defect engineering,phase engineering,and the corresponding mechanisms and structure-performance correlations.Then,typical applications of Te NMs in electrocatalysis are also discussed in detail.Finally,the existing key issues and main challenges of Te NMs for electrocatalysis are highlighted,and the development trend of Te NMs as electrocatalysts is expounded.This review provides new concepts to guide future directions for developing Te NMs-based electrocatalysts,thereby promoting their future wide applications in electrochemical energy systems.展开更多
β-Bromovinyl tellurides are new difuctional reagents which undergo palladium-catalyzed cross-coupling reaction with alkenes to give conjugated dienyl tellurides.
This paper describes the progress on the synthesis of organic selenides and tellurides and their application in organic synthesis. Low dent selenium and telluronium compounds having high reducing selectivity can be us...This paper describes the progress on the synthesis of organic selenides and tellurides and their application in organic synthesis. Low dent selenium and telluronium compounds having high reducing selectivity can be used to form carbon-hydrogen bonds an special reducing reagents. Telluronium ylides can react with aldehydes and ketones by Wittig-type condensation to produce (E)-configuration alkenes stereoselectively. α-Phenylselanyl arsonium ylides were prepared by transylidation reaction of arsonium ylides with phenylselanyl halides which can undergo Wittig-type reactions with carbonyl compounds to give (Z)-α-selanyl-α,β-unsaturated compounds with high stereoselectivity. Zirconium, tin, boron, halogen, metal or hetero-atom were introduced in organoselenium and telluronium compounds an new difunctional group reagents. Under transition metal catalysis, the corresponding cross coupling reactions provide new methods of formation of carbon-carbon double bonds, which were used in the stereoselective synthesis of the alkenes.展开更多
The two title compounds obtained by solid state reaction at high temperature were char-acierized as isomorphism by single--crystal X--ray diffraction. The space group of both crys-tals is C_(2v)~4-Pma2, with lattice c...The two title compounds obtained by solid state reaction at high temperature were char-acierized as isomorphism by single--crystal X--ray diffraction. The space group of both crys-tals is C_(2v)~4-Pma2, with lattice constants a = 7.955(1), b=6.258 (1), c=7 .203(2)A forI, and a =7.914 (1), b=6.237 (1), c=7.236 (1) ? for Ⅱ, Z=2. The structures were de-termined by normal method and refined to the final R = 0.074 and 0.083, respectively. Theresults show that the structure may be regarded as building by cluster unit with formulaNi_2M_2Te_4 (M =Nb or Ta) in which two Ni atoms and two M atoms form a rhombus, whilethe Te atoms are distorted tetrahedrally coordinated with both kinds of metal atoms. In thecluster unit there exist interactions between Ni atoms as well as between Ni and M atoms.In addition, all the cluster units are linked together not only by bridging Te atoms, but alsoby weaker metal-metal interactions, so as to form two--dimensional network. Therefore, thestructure may be represented by the formula [Ni_2M_2(μ_4--Te)_(6/3) (μ_4--Te)_(4/2) ]_∞. A preliminarymeasurement of electric conductivity shows that the crystals of the two title compounds aremetallic but their conductivities are anisotropic; those parallel to the a-b axes are about10~3Ω^(-1)·cm^(-1), whereas those along the c axis are about 10Ω^(-1)·cm^(-1).展开更多
A summary of research on the structure of Nb/Ta layered tellurides in the past period is reported. 14 compounds, which have been structurally characterized by X-ray diffraction work, are presented according to their s...A summary of research on the structure of Nb/Ta layered tellurides in the past period is reported. 14 compounds, which have been structurally characterized by X-ray diffraction work, are presented according to their structural features. The first two compounds, Nb2CrTe4 and Nb2Cu1.48Te4, are characterized in that the ternary atoms are inserted in the different layers from the Nb atoms. While in the other compounds, both kinds of metal atoms are inserted in the same layer. The six compounds with formula M2M′2Te4(M = Nb/Ta; M′ = Ni, Co, Fe) are characterized in that their structure can be described as construction by using cluster units 'M2M′2Te10' as building blocks. In the two metal-rich compounds, TaCo2Te2 and TaNi2Te2, Ta atom has a distorted mono-capped pentagonal prism configuration. The structure of TaFeTe3, TaNi2Te3 and NbNi2.34Te3can be described as building by the arrangement of double octahedral chains (DOC). In this connection, a selenide Ta2Ni2Se5 is also included by using the second type of DOC arrangement as the basis to build the structure.展开更多
The physical trend of group-I/tellurides is unexpected and contrary to the conventional wisdom. The present firstprinciples calculations give fundamental insights into the extent to which group-Ⅱ telluride compounds ...The physical trend of group-I/tellurides is unexpected and contrary to the conventional wisdom. The present firstprinciples calculations give fundamental insights into the extent to which group-Ⅱ telluride compounds present special properties upon mixing the d valence character. Our results provide explanations for the unexpected experimental observations based on the abnormal binding ordering of metal d electrons and their strong perturbation to the band edge states. The insights into the binary tellurides are useful for the study and control of the structural and chemical perturbation in their ternary alloys and heterostructures.展开更多
Manipulating the self-assembly of transition metal telluride nanocrystals(NCs) creates opportunities for exploring new properties and device applications. Iron ditelluride(FeTe2) has recently emerged as a new class of...Manipulating the self-assembly of transition metal telluride nanocrystals(NCs) creates opportunities for exploring new properties and device applications. Iron ditelluride(FeTe2) has recently emerged as a new class of magnetic semiconductor with three-dimensional(3D) magnetic ordering and narrow band gap structure, yet the self-assembly of FeTe2 NCs has not been achieved. Herein, the tree-like FeTe2 nanoarchitectures with orthorhombic crystal structure have been successfully synthesized by hot-injection solvent thermal approach using phosphine-free Te precursor. The morphology, size, and crystal structure have been investigated using transmission electron microscopy(TEM), high-resolution TEM(HRTEM),and powder x-ray diffraction(XRD). We study the formation process of tree-like FeTe2 NCs according to trace the change of the sample morphology with the reaction time. It was found that the FeTe2 nanoparticles show oriented aggregation and self-assembly behavior with the increase of reaction time, which is attributed to size-dependent magnetism properties of the samples. The magnetic interaction is thought to be the driving force of nanoparticle self-organization.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.52173267).
文摘Rational design of the components and microstructure is regarded as an efficacious strategy for the high-performance electromagnetic wave absorbing(EMWA)materials.Herein,the CoTe_(2)@MoS_(2)nanocomposites with CoTe_(2)nanorods and MoS_(2)nanosheets were synthesized via a hydrothermal method.The microstructure and composition of the samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The CoTe_(2)@MoS_(2)composite was composed of stacked CoTe_(2)as the core and intertwined MoS_(2)nanosheets as the shell.The electromagnetic parameters of the CoTe_(2)@MoS_(2)composites were investigated by vector network analyzer(VNA).The EMWA property of the composite showed a trend of first increasing and then decreasing with the increasing content of MoS_(2).When the mass ratio of MoS_(2)and CoTe_(2)was 1:1,the CoTe_(2)@MoS_(2)composite exhibited the minimum reflection loss value of-68.10 dB at 4.71 GHz,and the effective absorption bandwidth value might reach 4.64 GHz(13.08-17.72 GHz)at a matching thickness of 1.60 mm with filler loading of 50 wt.%.The extraordinary EMWA property was attributed to the optimized impedance matching,multiple scattering and reflections,dipole polarization,conductive loss,and interfacial polarization.Therefore,the present approach to the design of microstructure and interface engineering offers a crucial way to construct high-performance EMW absorbers.
基金supported by the International Collaboration Program of Jilin Provincial Department of Science and Technology,China(20230402051GH)the National Natural Science Foundation of China(51932003,51902050)+2 种基金the Open Project Program of Key Laboratory of Preparation and Application of Environmental friendly Materials(Jilin Normal University)of Ministry of China(2021006)the Fundamental Research Funds for the Central Universities JLU“Double-First Class”Discipline for Materials Science&Engineering。
文摘Owning various crystal structures and high theoretical capacity,metal tellurides are emerging as promising electrode materials for high-performance metal-ion batteries(MBs).Since metal telluride-based MBs are quite new,fundamental issues raise regarding the energy storage mechanism and other aspects affecting electrochemical performance.Severe volume expansion,low intrinsic conductivity and slow ion diffusion kinetics jeopardize the performance of metal tellurides,so that rational design and engineering are crucial to circumvent these disadvantages.Herein,this review provides an in-depth discussion of recent investigations and progresses of metal tellurides,beginning with a critical discussion on the energy storage mechanisms of metal tellurides in various MBs.In the following,recent design and engineering strategies of metal tellurides,including morphology engineering,compositing,defect engineering and heterostructure construction,for high-performance MBs are summarized.The primary focus is to present a comprehensive understanding of the structural evolution based on the mechanism and corresponding effects of dimension control,composition,electron configuration and structural complexity on the electrochemical performance.In closing,outlooks and prospects for future development of metal tellurides are proposed.This work also highlights the promising directions of design and engineering strategies of metal tellurides with high performance and low cost.
基金supported by the National Natural Science Foundation of China(grant no.22179089)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(grant no.KYCX22_3182).
文摘Lithium-sulfur(Li-S)batteries are broadly regarded as one of the most promising energy storage systems owing to their high-energy and low-cost features.Nevertheless,their practical implementation is plagued by the notorious polysulfide shuttling and sluggish reaction kinetics.Transition metal telluride has emerged as a promising electrocatalyst to expedite sulfur redox kinetics,even though its controllable and precise fabrication remains quite elusive.Herein,we propose the employment of a chemical vapor deposition approach to achieve in situ growth of Co-doped NiTe_(2)(Co-NiTe_(2))on vertically oriented graphene coated carbon cloth(VG/CC)substrate,in the pursuit of high-performance sulfur host material(Co-NiTe_(2)@VG/CC)in Li-S realms.Electrokinetic analysis and operando Raman spectroscopy characterization reveal the effective regulation capability of Co-NiTe_(2)@VG/CC with respect to polysulfide capture/conversion and Li2S decomposition.As a result,the Al-currentcollector-free Co-NiTe_(2)@VG/CC-based cathodes with typical sulfur loading exhibit outstanding cycling stability(93.8% capacity retention over 100 cycles at 0.5 C).Moreover,an areal capacity of 4.27 mAh cm^(-2) at 0.2 C can be harvested even at an elevated sulfur loading of 7.2 mg cm^(-2).
基金The authors thank the financial support from the National Natural Science Foundation of China(No.52201242 and 52250010)Natural Science Foundation of Jiangsu Province(No.BK20200386)+1 种基金Young Elite Scientists Sponsorship Program by CAST(No.2021QNRC001)the Fundamental Research Funds for the Central Universities(No.2242022R40018).
文摘Exploiting high-rate anode materials with fast K+diffusion is intriguing for the development of advanced potassium-ion batteries(KIBs)but remains unrealized.Here,heterostructure engineering is proposed to construct the dual transition metal tellurides(CoTe_(2)/ZnTe),which are anchored onto two-dimensional(2D)Ti_(3)C_(2)T_(x)MXene nanosheets.Various theoretical modeling and experimental findings reveal that heterostructure engineering can regulate the electronic structures of CoTe_(2)/ZnTe interfaces,improving K+diffusion and adsorption.In addition,the different work functions between CoTe_(2)/ZnTe induce a robust built-in electric field at the CoTe_(2)/ZnTe interface,providing a strong driving force to facilitate charge transport.Moreover,the conductive and elastic Ti_(3)C_(2)T_(x)can effectively promote electrode conductivity and alleviate the volume change of CoTe_(2)/ZnTe heterostructures upon cycling.Owing to these merits,the resulting CoTe_(2)/ZnTe/Ti_(3)C_(2)T_(x)(CZT)exhibit excellent rate capability(137.0 mAh g^(-1)at 10 A g^(-1))and cycling stability(175.3 mAh g^(-1)after 4000 cycles at 3.0 A g^(-1),with a high capacity retention of 89.4%).More impressively,the CZT-based full cells demonstrate high energy density(220.2 Wh kg^(-1))and power density(837.2 W kg^(-1)).This work provides a general and effective strategy by integrating heterostructure engineering and 2D material nanocompositing for designing advanced high-rate anode materials for next-generation KIBs.
基金Science and Technology Project of Sichuan Province,Grant/Award Numbers:2022YFH0042,2022YFH0088,2022YFH0111,2022YFH0112National Natural Science Foundation of China,Grant/Award Numbers:82001829,52161145402,52173133+1 种基金State Key Laboratory of Polymer Materials Engineering,Grant/Award Number:sklpme2021-4-02Fundamental Research Funds for the Central Universities.
文摘With the dramatic developments of renewable and environmental-friendly electrochemical energy conversion systems,there is an urgent need to fabricate durable and efficient electrocatalysts to address the limitation of high overpotentials exceeding thermodynamic requirements to facilitate practical applications.Recently,tellurium-based nanomaterials(Te NMs)with unique chemical,electronic,and topological properties,including Te-derived nanostructures and transition metal tellurides(TMTs),have emerged as one of the most promising electrocatalytic materials.In the absence of comprehensive and guiding reviews,this review comprehensively summarizes the main advances in designing emerging Te NMs for electrocatalysis.First,the engineering strategies and principles of Te NMs to enhance their electrocatalytic activity and stability from the nanostructures to the catalytic atoms are discussed in detail,especially on the chemical/physical/multiplex templating strategies,heteroatom doping,vacancy/defect engineering,phase engineering,and the corresponding mechanisms and structure-performance correlations.Then,typical applications of Te NMs in electrocatalysis are also discussed in detail.Finally,the existing key issues and main challenges of Te NMs for electrocatalysis are highlighted,and the development trend of Te NMs as electrocatalysts is expounded.This review provides new concepts to guide future directions for developing Te NMs-based electrocatalysts,thereby promoting their future wide applications in electrochemical energy systems.
基金This work was supported by Natural Science Foundation of Zhejiang Province.
文摘β-Bromovinyl tellurides are new difuctional reagents which undergo palladium-catalyzed cross-coupling reaction with alkenes to give conjugated dienyl tellurides.
基金Project supported by the National Natural Science Foundation of China (No. 29493804)the Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, China
文摘This paper describes the progress on the synthesis of organic selenides and tellurides and their application in organic synthesis. Low dent selenium and telluronium compounds having high reducing selectivity can be used to form carbon-hydrogen bonds an special reducing reagents. Telluronium ylides can react with aldehydes and ketones by Wittig-type condensation to produce (E)-configuration alkenes stereoselectively. α-Phenylselanyl arsonium ylides were prepared by transylidation reaction of arsonium ylides with phenylselanyl halides which can undergo Wittig-type reactions with carbonyl compounds to give (Z)-α-selanyl-α,β-unsaturated compounds with high stereoselectivity. Zirconium, tin, boron, halogen, metal or hetero-atom were introduced in organoselenium and telluronium compounds an new difunctional group reagents. Under transition metal catalysis, the corresponding cross coupling reactions provide new methods of formation of carbon-carbon double bonds, which were used in the stereoselective synthesis of the alkenes.
基金Project supported by the National Natural Science Foundation of China.
文摘The two title compounds obtained by solid state reaction at high temperature were char-acierized as isomorphism by single--crystal X--ray diffraction. The space group of both crys-tals is C_(2v)~4-Pma2, with lattice constants a = 7.955(1), b=6.258 (1), c=7 .203(2)A forI, and a =7.914 (1), b=6.237 (1), c=7.236 (1) ? for Ⅱ, Z=2. The structures were de-termined by normal method and refined to the final R = 0.074 and 0.083, respectively. Theresults show that the structure may be regarded as building by cluster unit with formulaNi_2M_2Te_4 (M =Nb or Ta) in which two Ni atoms and two M atoms form a rhombus, whilethe Te atoms are distorted tetrahedrally coordinated with both kinds of metal atoms. In thecluster unit there exist interactions between Ni atoms as well as between Ni and M atoms.In addition, all the cluster units are linked together not only by bridging Te atoms, but alsoby weaker metal-metal interactions, so as to form two--dimensional network. Therefore, thestructure may be represented by the formula [Ni_2M_2(μ_4--Te)_(6/3) (μ_4--Te)_(4/2) ]_∞. A preliminarymeasurement of electric conductivity shows that the crystals of the two title compounds aremetallic but their conductivities are anisotropic; those parallel to the a-b axes are about10~3Ω^(-1)·cm^(-1), whereas those along the c axis are about 10Ω^(-1)·cm^(-1).
文摘A summary of research on the structure of Nb/Ta layered tellurides in the past period is reported. 14 compounds, which have been structurally characterized by X-ray diffraction work, are presented according to their structural features. The first two compounds, Nb2CrTe4 and Nb2Cu1.48Te4, are characterized in that the ternary atoms are inserted in the different layers from the Nb atoms. While in the other compounds, both kinds of metal atoms are inserted in the same layer. The six compounds with formula M2M′2Te4(M = Nb/Ta; M′ = Ni, Co, Fe) are characterized in that their structure can be described as construction by using cluster units 'M2M′2Te10' as building blocks. In the two metal-rich compounds, TaCo2Te2 and TaNi2Te2, Ta atom has a distorted mono-capped pentagonal prism configuration. The structure of TaFeTe3, TaNi2Te3 and NbNi2.34Te3can be described as building by the arrangement of double octahedral chains (DOC). In this connection, a selenide Ta2Ni2Se5 is also included by using the second type of DOC arrangement as the basis to build the structure.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10847111 and 61006091)the Startup Project for Ph. D. of Guangdong University of Technology (Grant No. 083034)the Fundamental Research Funds for the Central Universities of South China University of Technology (Grant No. 2009ZM0022)
文摘The physical trend of group-I/tellurides is unexpected and contrary to the conventional wisdom. The present firstprinciples calculations give fundamental insights into the extent to which group-Ⅱ telluride compounds present special properties upon mixing the d valence character. Our results provide explanations for the unexpected experimental observations based on the abnormal binding ordering of metal d electrons and their strong perturbation to the band edge states. The insights into the binary tellurides are useful for the study and control of the structural and chemical perturbation in their ternary alloys and heterostructures.
基金Project supported by the National Natural Science Foundation of China(Grant No.11874027)the China Postdoctoral Science Foundation(Grant Nos.2019T120233 and 2017M621198)
文摘Manipulating the self-assembly of transition metal telluride nanocrystals(NCs) creates opportunities for exploring new properties and device applications. Iron ditelluride(FeTe2) has recently emerged as a new class of magnetic semiconductor with three-dimensional(3D) magnetic ordering and narrow band gap structure, yet the self-assembly of FeTe2 NCs has not been achieved. Herein, the tree-like FeTe2 nanoarchitectures with orthorhombic crystal structure have been successfully synthesized by hot-injection solvent thermal approach using phosphine-free Te precursor. The morphology, size, and crystal structure have been investigated using transmission electron microscopy(TEM), high-resolution TEM(HRTEM),and powder x-ray diffraction(XRD). We study the formation process of tree-like FeTe2 NCs according to trace the change of the sample morphology with the reaction time. It was found that the FeTe2 nanoparticles show oriented aggregation and self-assembly behavior with the increase of reaction time, which is attributed to size-dependent magnetism properties of the samples. The magnetic interaction is thought to be the driving force of nanoparticle self-organization.
