分别采用超声微波溶剂热法、常压溶剂热法及高压溶剂热法制备In_2Se_3/CuSe粉体,研究不同方法制备In_2Se_3/CuSe粉体的物相、形貌,并利用涂覆–快速热处理法制作薄膜太阳电池吸收层。通过XRD、Raman、FESEM和TEM对样品的物相、形貌和组...分别采用超声微波溶剂热法、常压溶剂热法及高压溶剂热法制备In_2Se_3/CuSe粉体,研究不同方法制备In_2Se_3/CuSe粉体的物相、形貌,并利用涂覆–快速热处理法制作薄膜太阳电池吸收层。通过XRD、Raman、FESEM和TEM对样品的物相、形貌和组成进行了表征。结果表明:超声微波溶剂热法和常压溶剂热法得到的产物是以In_2Se_3+CuSe混合相的形式存在,高压溶剂热法合成的In_2Se_3/CuSe粉体则呈核壳结构,(以In_2Se_3为核,CuSe为壳)。涂覆–快速热处理法制备CIS薄膜的FESEM照片结果表明,高压溶剂热法合成的In_2Se_3/CuSe更容易获得平整致密的薄膜。将该CIS薄膜直接用于电池器件的组装,获得的光电性能参数:Voc为50 m V,Jsc为8 m A/cm^2。展开更多
Experiments on the thermal decomposition of CuSe were carried out by using a thermogravimetric analyzer(TGA)at different heating rates.The kinetic parameters and mechanisms were discussed based on model-free and model...Experiments on the thermal decomposition of CuSe were carried out by using a thermogravimetric analyzer(TGA)at different heating rates.The kinetic parameters and mechanisms were discussed based on model-free and model-based analyses.The decomposition rate and decomposition behavior of CuSe were investigated by using a vacuum thermogravimetric furnace.The results showed that the R3 model was identified as the most probable mechanism function under the present experimental conditions.The average values of activation energy and the pre-exponential factor were 12.344 J/mol and 0.152 s^(−1),respectively.The actual decomposition rate of CuSe was found to be 0.0030 g/(cm^(2)·min).展开更多
In this article, a computational analysis has been performed on the structural properties and predominantly on the electronic properties of the α-CuSe （klockmannite） using density functional theory. The studies in ...In this article, a computational analysis has been performed on the structural properties and predominantly on the electronic properties of the α-CuSe （klockmannite） using density functional theory. The studies in this work show that the best structural results, in comparison to the experimental values, belong to the PBEsol-GGA and WC-GGA functionals. However, the best results for the bulk modulus and density of states （DOSs） are related to the local density approximation （LDA） functional. Through utilized approaches, the LDA is chosen to investigate the electronic structure. The results of the electronic properties and geometric optimization of α-CuSe respectively show that this compound is conductive and non-magnetic. The curvatures of the energy bands crossing the Fermi level explicitly reveal that major charge carriers in CuSe are holes, whose density is estimated to be 0.86×1022 hole/cm3. In particular, the Fermi surfaces in the first Brillouin zone demonstrate interplane conductivity between （001） planes. Moreover, the charge carriers among them are electrons and holes simultaneously. The conductivity in CuSe is mainly due to the hybridization between the d orbitals of Cu atoms and the p orbitals of Se atoms. The former orbitals have the dual nature of localization and itinerancy.展开更多
Two-dimensional monolayer copper selenide(CuSe)has been epitaxially grown and predicted to host the Dirac nodal line fermion(DNLF).However,the metallic state of monolayer CuSe inhibits the potential application of nan...Two-dimensional monolayer copper selenide(CuSe)has been epitaxially grown and predicted to host the Dirac nodal line fermion(DNLF).However,the metallic state of monolayer CuSe inhibits the potential application of nanoelectronic devices in which a band gap is needed to realize on/off properties.Here,we engineer the band structure of monolayer CuSe which is an analogue of a p-doped system via external atomic modification in an effort to realize the semiconducting state.We find that the H and Li modified monolayer CuSe shifts the energy band and opens an energy gap around the Fermi level.Interestingly,both the atomic and electronic structures of monolayer CuHSe and CuLiSe are very different.The H atoms bind on top of Se atoms of monolayer CuSe with Se-H polar covalent bonds,annihilating the DNLF band of monolayer CuSe dominated by Se orbitals.In contrast,Li atoms prefer to adsorb at the hexagonal center of CuSe,preserving the DNLF band of monolayer CuSe dominated by Se orbitals,but opening band gaps due to a slight buckling of the CuSe layer.The realization of metal-to-semiconductor transition from monolayer CuSe to CuXSe(X=H,Li)as revealed by first-principles calculations makes it possible to use CuSe in future electronic devices.展开更多
The development of highly efficient catalysts in the cathodes of rechargeable Li-O_(2) batteries is a considerable challenge.To enhance the electrochemical performance of the Li-O_(2) battery,it is essential to choose...The development of highly efficient catalysts in the cathodes of rechargeable Li-O_(2) batteries is a considerable challenge.To enhance the electrochemical performance of the Li-O_(2) battery,it is essential to choose a suitable catalyst material.Copper selenide(CuSe)is considered as a more promising cathode catalyst material for Li-O_(2) battery due to its better conductivity and rich electrochemical active sites.However,its electrochemical reaction and fundamental catalytic mechanism remain unclear till now.Herein,in-situ environmental transmission electron microscopy technique was used to study the catalysis mechanism of the CuSe nanosheets in Li-O_(2) batteries during discharge and charge processes.It is found that Li_(2)O was formed and decomposed around the ultrafine-grained Cu during the discharge and charge processes,respectively,demonstrating excellent cycling.This indicate that the freshly formed ultrafine-grained Cu in the conversion reaction catalyzed the latter four-electron-transfer oxygen reduction reaction,leading to the formation of Li_(2)O.Our study provides important understanding of the electrochemistry of the LiO_(2) nanobatteries,which will aid the development of high-performance Li-O_(2) batteries for energy storage applications.展开更多
We perform molecular beam epitaxy growth and scanning tunneling microscopy study of copper diselenide （CuSe2 ） films on SrTiO3 （001）. Using a Se-rich condition, the single-phase pyrite CuSe2 grows in the Stranski-...We perform molecular beam epitaxy growth and scanning tunneling microscopy study of copper diselenide （CuSe2 ） films on SrTiO3 （001）. Using a Se-rich condition, the single-phase pyrite CuSe2 grows in the Stranski-Krastanov （layer-plus-island） mode with a preferential orientation of （111）. Our careful inspection of both the as-grown and post-annealed CuSe2 films at various temperatures invariably shows a Cu-terminated surface, which, depending on the annealing temperature, reconstructs into two distinct structures 2 ×√3 and √x ×√3-R30°. The Cu termi- nation is supported by the depressed density of states near the Fermi level, measured by in-situ low temperature scanning tunneling spectroscopy. Our study helps understand the preparation and surface chemistry of transition metal pyrite dichalcogenides thin films.展开更多
由于资源储量丰富,钠离子电池已经成为下一代储能电池的有力候选方案之一.过渡金属硒化物由于具有易于制备、导电性能较好等优点而引起广泛关注.本文使用溶剂热方法成功地制备出六方相CuSe纳米片,并将其作为钠离子电池负极材料,结合多...由于资源储量丰富,钠离子电池已经成为下一代储能电池的有力候选方案之一.过渡金属硒化物由于具有易于制备、导电性能较好等优点而引起广泛关注.本文使用溶剂热方法成功地制备出六方相CuSe纳米片,并将其作为钠离子电池负极材料,结合多种测试及表征手段对其储钠性能与电化学反应机理进行了研究.电化学测试表明CuSe具有优异的电化学性能.在5 A g^(-1)电流密度下的可逆容量为183.5 mAh g^(-1),容量保持率为70.7%(相对0.1 A g^(-1)电流密度下的可逆容量而言).在2 A g^(-1)循环800圈后,容量保持率高达97.4%.非原位X射线粉末衍射和选区电子衍射测试结果表明,CuSe在储钠过程中会发生不可逆的转化反应生成Cu_(2-x)Se,后续的循环实际上是Cu_(2-x)Se进行钠离子的转化反应.展开更多
A simple green hydrothermal template-free method was developed to prepare single-crystalline superstructures of fern- wort-like copper selenide （CuSe） in large-scale by using polyvinylpyrrolidone （PVP） as both red...A simple green hydrothermal template-free method was developed to prepare single-crystalline superstructures of fern- wort-like copper selenide （CuSe） in large-scale by using polyvinylpyrrolidone （PVP） as both reductant and surfactant for the first time. Time-dependent morphologic evolution was made in order to explore the formation mechanism of the as-prepared product. The copper selenides with different morphologies, phases and structural forms could be prepared by varying the synthesis parameters, such as precursor molar ratios, precursor combinations, and the molecular weight of PVP. The fernwort-like superstructures of CuSe show excellent Fenton-like catalytic activities in degrading malachite green （MG） and rhodamine B （RhB）. These catalysts play an important role in the degradation process of MG and RhB solution with the aid of H202 which can yield highly reactive hydroxyl radicals （HO.）. Besides, the as-prepared CuSe catalyst is stable and reusable, thus it could be applied to the treatment of the dye contaminated waste water.展开更多
文摘分别采用超声微波溶剂热法、常压溶剂热法及高压溶剂热法制备In_2Se_3/CuSe粉体,研究不同方法制备In_2Se_3/CuSe粉体的物相、形貌,并利用涂覆–快速热处理法制作薄膜太阳电池吸收层。通过XRD、Raman、FESEM和TEM对样品的物相、形貌和组成进行了表征。结果表明:超声微波溶剂热法和常压溶剂热法得到的产物是以In_2Se_3+CuSe混合相的形式存在,高压溶剂热法合成的In_2Se_3/CuSe粉体则呈核壳结构,(以In_2Se_3为核,CuSe为壳)。涂覆–快速热处理法制备CIS薄膜的FESEM照片结果表明,高压溶剂热法合成的In_2Se_3/CuSe更容易获得平整致密的薄膜。将该CIS薄膜直接用于电池器件的组装,获得的光电性能参数:Voc为50 m V,Jsc为8 m A/cm^2。
基金supported by the Basic Research Plan of Yunnan Province,China(No.2019FA020)the Yunling Scholars of Yunnan Province,China(No.KKRC201952012)the Leading Talents of Industrial Technology in Ten Thousand Talents Plan of Yunnan Province,China,and the Scientist Studio of Yunnan Province,China.
文摘Experiments on the thermal decomposition of CuSe were carried out by using a thermogravimetric analyzer(TGA)at different heating rates.The kinetic parameters and mechanisms were discussed based on model-free and model-based analyses.The decomposition rate and decomposition behavior of CuSe were investigated by using a vacuum thermogravimetric furnace.The results showed that the R3 model was identified as the most probable mechanism function under the present experimental conditions.The average values of activation energy and the pre-exponential factor were 12.344 J/mol and 0.152 s^(−1),respectively.The actual decomposition rate of CuSe was found to be 0.0030 g/(cm^(2)·min).
基金performed based on research project number 2054361 in the University of Isfahan (UI), Isfahan, Iran
文摘In this article, a computational analysis has been performed on the structural properties and predominantly on the electronic properties of the α-CuSe （klockmannite） using density functional theory. The studies in this work show that the best structural results, in comparison to the experimental values, belong to the PBEsol-GGA and WC-GGA functionals. However, the best results for the bulk modulus and density of states （DOSs） are related to the local density approximation （LDA） functional. Through utilized approaches, the LDA is chosen to investigate the electronic structure. The results of the electronic properties and geometric optimization of α-CuSe respectively show that this compound is conductive and non-magnetic. The curvatures of the energy bands crossing the Fermi level explicitly reveal that major charge carriers in CuSe are holes, whose density is estimated to be 0.86×1022 hole/cm3. In particular, the Fermi surfaces in the first Brillouin zone demonstrate interplane conductivity between （001） planes. Moreover, the charge carriers among them are electrons and holes simultaneously. The conductivity in CuSe is mainly due to the hybridization between the d orbitals of Cu atoms and the p orbitals of Se atoms. The former orbitals have the dual nature of localization and itinerancy.
基金supported by the National Key Research&Development Projects of China(Grant No.2016YFA0202300)the National Natural Science Foundation of China(Grant No.61888102)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000).
文摘Two-dimensional monolayer copper selenide(CuSe)has been epitaxially grown and predicted to host the Dirac nodal line fermion(DNLF).However,the metallic state of monolayer CuSe inhibits the potential application of nanoelectronic devices in which a band gap is needed to realize on/off properties.Here,we engineer the band structure of monolayer CuSe which is an analogue of a p-doped system via external atomic modification in an effort to realize the semiconducting state.We find that the H and Li modified monolayer CuSe shifts the energy band and opens an energy gap around the Fermi level.Interestingly,both the atomic and electronic structures of monolayer CuHSe and CuLiSe are very different.The H atoms bind on top of Se atoms of monolayer CuSe with Se-H polar covalent bonds,annihilating the DNLF band of monolayer CuSe dominated by Se orbitals.In contrast,Li atoms prefer to adsorb at the hexagonal center of CuSe,preserving the DNLF band of monolayer CuSe dominated by Se orbitals,but opening band gaps due to a slight buckling of the CuSe layer.The realization of metal-to-semiconductor transition from monolayer CuSe to CuXSe(X=H,Li)as revealed by first-principles calculations makes it possible to use CuSe in future electronic devices.
基金financially supported by the National Natural Science Foundation of China(Nos.52022088,51971245)Natural Science Foundation of Hebei Province(No.F2021203097)China Postdoctoral Science Foundation(No.2021M702756)。
文摘The development of highly efficient catalysts in the cathodes of rechargeable Li-O_(2) batteries is a considerable challenge.To enhance the electrochemical performance of the Li-O_(2) battery,it is essential to choose a suitable catalyst material.Copper selenide(CuSe)is considered as a more promising cathode catalyst material for Li-O_(2) battery due to its better conductivity and rich electrochemical active sites.However,its electrochemical reaction and fundamental catalytic mechanism remain unclear till now.Herein,in-situ environmental transmission electron microscopy technique was used to study the catalysis mechanism of the CuSe nanosheets in Li-O_(2) batteries during discharge and charge processes.It is found that Li_(2)O was formed and decomposed around the ultrafine-grained Cu during the discharge and charge processes,respectively,demonstrating excellent cycling.This indicate that the freshly formed ultrafine-grained Cu in the conversion reaction catalyzed the latter four-electron-transfer oxygen reduction reaction,leading to the formation of Li_(2)O.Our study provides important understanding of the electrochemistry of the LiO_(2) nanobatteries,which will aid the development of high-performance Li-O_(2) batteries for energy storage applications.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11374336 and 61176078
文摘We perform molecular beam epitaxy growth and scanning tunneling microscopy study of copper diselenide （CuSe2 ） films on SrTiO3 （001）. Using a Se-rich condition, the single-phase pyrite CuSe2 grows in the Stranski-Krastanov （layer-plus-island） mode with a preferential orientation of （111）. Our careful inspection of both the as-grown and post-annealed CuSe2 films at various temperatures invariably shows a Cu-terminated surface, which, depending on the annealing temperature, reconstructs into two distinct structures 2 ×√3 and √x ×√3-R30°. The Cu termi- nation is supported by the depressed density of states near the Fermi level, measured by in-situ low temperature scanning tunneling spectroscopy. Our study helps understand the preparation and surface chemistry of transition metal pyrite dichalcogenides thin films.
文摘由于资源储量丰富,钠离子电池已经成为下一代储能电池的有力候选方案之一.过渡金属硒化物由于具有易于制备、导电性能较好等优点而引起广泛关注.本文使用溶剂热方法成功地制备出六方相CuSe纳米片,并将其作为钠离子电池负极材料,结合多种测试及表征手段对其储钠性能与电化学反应机理进行了研究.电化学测试表明CuSe具有优异的电化学性能.在5 A g^(-1)电流密度下的可逆容量为183.5 mAh g^(-1),容量保持率为70.7%(相对0.1 A g^(-1)电流密度下的可逆容量而言).在2 A g^(-1)循环800圈后,容量保持率高达97.4%.非原位X射线粉末衍射和选区电子衍射测试结果表明,CuSe在储钠过程中会发生不可逆的转化反应生成Cu_(2-x)Se,后续的循环实际上是Cu_(2-x)Se进行钠离子的转化反应.
基金supported by the National Natural Science Foundation of China (21375109)
文摘A simple green hydrothermal template-free method was developed to prepare single-crystalline superstructures of fern- wort-like copper selenide （CuSe） in large-scale by using polyvinylpyrrolidone （PVP） as both reductant and surfactant for the first time. Time-dependent morphologic evolution was made in order to explore the formation mechanism of the as-prepared product. The copper selenides with different morphologies, phases and structural forms could be prepared by varying the synthesis parameters, such as precursor molar ratios, precursor combinations, and the molecular weight of PVP. The fernwort-like superstructures of CuSe show excellent Fenton-like catalytic activities in degrading malachite green （MG） and rhodamine B （RhB）. These catalysts play an important role in the degradation process of MG and RhB solution with the aid of H202 which can yield highly reactive hydroxyl radicals （HO.）. Besides, the as-prepared CuSe catalyst is stable and reusable, thus it could be applied to the treatment of the dye contaminated waste water.
