Broadband photodetectors with self-driven functions have attracted intensive scientific interest due to their low energy consumption and high optical gain.However,high-performance broadband self-driven photodetectors ...Broadband photodetectors with self-driven functions have attracted intensive scientific interest due to their low energy consumption and high optical gain.However,high-performance broadband self-driven photodetectors are still a significant challenge due to the complex fabrication processes,environmental toxicity,high production costs of traditional 3D semiconductor materials and sharply raised contact resistance,severe interfacial recombination of 2D materials and 2D/3D mixed dimension heterojunction.Here,1D p-Te/2D n-Bi_(2)Te_(3) heterojunctions are constructed by the simple and low-cost hydrothermal method.1D p-Te/2D n-Bi_(2)Te_(3) devices are applied in photoelectrochemical(PEC)photodetectors,with their high performance attributed to the good interfacial contacts reducing interface recombination.The device demonstrated a broad wavelength range(365–850 nm)with an Iph/Idark as high as 377.45.The R_(i),D^(*),and external quantum efficiency(EQE)values of the device were as high as 12.07 mA/W,5.87×10^(10) Jones,and 41.05%,respectively,which were significantly better than the performance of the prepared Bi_(2)Te_(3) and Te devices.A comparison of the freshly fabricated device and the device after 30 days showed that 1D p-Te/2D n-Bi_(2)Te_(3) had excellent stability with only 18.08%decay of photocurrent.It is anticipated that this work will provide new emerging material for future design and preparation of a high-performance self-driven broadband photodetector.展开更多
The development of thermodynamically controllable synthetic strategy to manipulate the morphology of ZIF-8 without capping agent is essential to help understanding their facet effect and the structure-activity relatio...The development of thermodynamically controllable synthetic strategy to manipulate the morphology of ZIF-8 without capping agent is essential to help understanding their facet effect and the structure-activity relationship of single atom catalysts derived from ZIF-8.Here,we prepared ZIF-8 with different morphologies(cube,truncated rhombododecahedral and rhombododecahedral)and thus area ratio of exposed{100},{110}facets by a thermodynamically controllable synthetic strategy.When the reaction proceeds under room temperature(30℃),the assembling of ZIF-8 followed an area-reducing layered growth mode,while switched to an integral layered growth mode at lower temperature-40℃.Moreover,this strategy also works to obtain ZIF-8 encapsulated with metal precursors(Fe(acac)_(3),Cu(acac)_(2)and Co(acac)_(2)).Single Fe atom anchored on nitrogen doped carbon catalysts(SA-Fe/CN)derived from Fe-ZIF-8 retain their original morphologies and the unsaturated surface-active sites on{100}facet,which further displays different catalytic performance towards oxygen reduction reaction(ORR).This work not only reveals the different growth pattern of ZIF-8,but also points out a new direction for designing and synthesizing MOFs with different morphology rationally.展开更多
Developing the novel ionic liquids as the potential substitutes for conventional organic solvents in extraction of the rare-earth metals is highly desirable but challenges still remain.In this study,the welldesigned c...Developing the novel ionic liquids as the potential substitutes for conventional organic solvents in extraction of the rare-earth metals is highly desirable but challenges still remain.In this study,the welldesigned carboxylic acid functionalized phosphonium based ionic liquids,(4-carboxyl)butyl-trioctylphosphonium chloride/nitrate,were synthesized and characterized.The as-prepared samples were tested as the undiluted hydrophobic acidic extractant for rare-earth metal ions,affording the maximal loading of 3 mol/mol towards Nd(Ⅲ)in aqueous solution and the remarkable stripping performance.The results also reveal their excellent extractability and selectivity for Sc(Ⅲ)in the mixtures of six rare-earth ions,as well as the outstanding separation properties between rare-earth and first row transition-metal ions(i.e.,La/Ni,Sm/Co).Moreover,the extraction mechanism indicates that the extracted rare-earth complex via a proton exchange in the ionic liquid phase is structurally similar to the complexes obtained with neutral extractants.This work presents a prototype for the fabrication of the hydrophobic cation-functionalized ionic liquids for highly efficient rare-earth extraction and provides the future application in recycling of rare-earth metals from the spent magnets.展开更多
The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe,with the ultimate aim of mapping the large scale structure and ...The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe,with the ultimate aim of mapping the large scale structure and measuring cosmological parameters such as the dark energy equation of state.Each of its three parallel cylinder reflectors is oriented in the north-south direction,and the array has a large field of view.As the Earth rotates,the northern sky is observed by drift scanning.The array is located in Hongliuxia,a radio-quiet site in Xinjiang,and saw its first light in September 2016.In this first data analysis paper for the Tianlai cylinder array,we discuss the sub-system qualification tests,and present basic system performance obtained from preliminary analysis of the commissioning observations during 2016-2018.We show typical interferometric visibility data,from which we derive the actual beam profile in the east-west direction and the frequency band-pass response.We describe also the calibration process to determine the complex gains for the array elements,either using bright astronomical point sources,or an artificial on site calibrator source,and discuss the instrument response stability,crucial for transit interferometry.Based on this analysis,we find a system temperature of about 90 K,and we also estimate the sensitivity of the array.展开更多
基金supported by the National Key Research and Development Program of China(No.2019YFA0705201)the National Natural Science Foundation of China(No.U2032129).
文摘Broadband photodetectors with self-driven functions have attracted intensive scientific interest due to their low energy consumption and high optical gain.However,high-performance broadband self-driven photodetectors are still a significant challenge due to the complex fabrication processes,environmental toxicity,high production costs of traditional 3D semiconductor materials and sharply raised contact resistance,severe interfacial recombination of 2D materials and 2D/3D mixed dimension heterojunction.Here,1D p-Te/2D n-Bi_(2)Te_(3) heterojunctions are constructed by the simple and low-cost hydrothermal method.1D p-Te/2D n-Bi_(2)Te_(3) devices are applied in photoelectrochemical(PEC)photodetectors,with their high performance attributed to the good interfacial contacts reducing interface recombination.The device demonstrated a broad wavelength range(365–850 nm)with an Iph/Idark as high as 377.45.The R_(i),D^(*),and external quantum efficiency(EQE)values of the device were as high as 12.07 mA/W,5.87×10^(10) Jones,and 41.05%,respectively,which were significantly better than the performance of the prepared Bi_(2)Te_(3) and Te devices.A comparison of the freshly fabricated device and the device after 30 days showed that 1D p-Te/2D n-Bi_(2)Te_(3) had excellent stability with only 18.08%decay of photocurrent.It is anticipated that this work will provide new emerging material for future design and preparation of a high-performance self-driven broadband photodetector.
基金This work was supported by the National Natural Science Foundation of China(No.22102218)the Natural Science Foundation of Hunan Province(No.2020JJ4684)+1 种基金the science and technology innovation Program of Hunan Province(No.2022RC1110)the Open Sharing Fund for the Large-scale Instruments and Equipments of Central South University(No.CSUZC202221).
文摘The development of thermodynamically controllable synthetic strategy to manipulate the morphology of ZIF-8 without capping agent is essential to help understanding their facet effect and the structure-activity relationship of single atom catalysts derived from ZIF-8.Here,we prepared ZIF-8 with different morphologies(cube,truncated rhombododecahedral and rhombododecahedral)and thus area ratio of exposed{100},{110}facets by a thermodynamically controllable synthetic strategy.When the reaction proceeds under room temperature(30℃),the assembling of ZIF-8 followed an area-reducing layered growth mode,while switched to an integral layered growth mode at lower temperature-40℃.Moreover,this strategy also works to obtain ZIF-8 encapsulated with metal precursors(Fe(acac)_(3),Cu(acac)_(2)and Co(acac)_(2)).Single Fe atom anchored on nitrogen doped carbon catalysts(SA-Fe/CN)derived from Fe-ZIF-8 retain their original morphologies and the unsaturated surface-active sites on{100}facet,which further displays different catalytic performance towards oxygen reduction reaction(ORR).This work not only reveals the different growth pattern of ZIF-8,but also points out a new direction for designing and synthesizing MOFs with different morphology rationally.
基金Project supported by the National Natural Science Foundation of China(51804223)。
文摘Developing the novel ionic liquids as the potential substitutes for conventional organic solvents in extraction of the rare-earth metals is highly desirable but challenges still remain.In this study,the welldesigned carboxylic acid functionalized phosphonium based ionic liquids,(4-carboxyl)butyl-trioctylphosphonium chloride/nitrate,were synthesized and characterized.The as-prepared samples were tested as the undiluted hydrophobic acidic extractant for rare-earth metal ions,affording the maximal loading of 3 mol/mol towards Nd(Ⅲ)in aqueous solution and the remarkable stripping performance.The results also reveal their excellent extractability and selectivity for Sc(Ⅲ)in the mixtures of six rare-earth ions,as well as the outstanding separation properties between rare-earth and first row transition-metal ions(i.e.,La/Ni,Sm/Co).Moreover,the extraction mechanism indicates that the extracted rare-earth complex via a proton exchange in the ionic liquid phase is structurally similar to the complexes obtained with neutral extractants.This work presents a prototype for the fabrication of the hydrophobic cation-functionalized ionic liquids for highly efficient rare-earth extraction and provides the future application in recycling of rare-earth metals from the spent magnets.
基金support of the Astronomical Technology Center of National Astronomical Observatories of China(NAOC)support of Ministry of Science and Technology(MOST)(Grant No.2012AA121701)+10 种基金supported by MOST(Grant Nos.2016YFE0100300,and 2018YFE0120800)the National Natural Science Foundation of China(NSFC)(Grant Nos.11633004,11473044,and 11653003)the Chinese Academy of Sciences(CAS)(Grant No.QYZDJ-SSW-SLH017)support of the NSFC-CAS Joint Fund of Astronomy(Grant No.U1631118)partially supported by the National Key R&D Program(Grant No.2017YFA0402603)the CAS Interdisciplinary Innovation Team(Grant No.JCTD-2019-05)support of NSFC(Grant No.U1501501)the Tianhe-1 supercomputerpartially supported by the US National Science Foundation(NSF)Award(Grant No.AST-1616554)partial support from Centre National de la Recherche Scientifique(CNRS)via IN2P3&INSU,Observatoire de ParisIrfu/CEA。
文摘The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe,with the ultimate aim of mapping the large scale structure and measuring cosmological parameters such as the dark energy equation of state.Each of its three parallel cylinder reflectors is oriented in the north-south direction,and the array has a large field of view.As the Earth rotates,the northern sky is observed by drift scanning.The array is located in Hongliuxia,a radio-quiet site in Xinjiang,and saw its first light in September 2016.In this first data analysis paper for the Tianlai cylinder array,we discuss the sub-system qualification tests,and present basic system performance obtained from preliminary analysis of the commissioning observations during 2016-2018.We show typical interferometric visibility data,from which we derive the actual beam profile in the east-west direction and the frequency band-pass response.We describe also the calibration process to determine the complex gains for the array elements,either using bright astronomical point sources,or an artificial on site calibrator source,and discuss the instrument response stability,crucial for transit interferometry.Based on this analysis,we find a system temperature of about 90 K,and we also estimate the sensitivity of the array.