Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the r...Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.展开更多
Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier t...Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and vibrating sample magnetometry,respectively.Photocatalytic performance of the straw@Fe_(3)O_(4)/Cu_(2)O was evaluated by measuring the degradation of methyl orange(MO)under irradiation of visible light.The introduction of Fe3O4 not only endowed the straw@Fe_(3)O_(4)/Cu_(2)O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs.The active species capture experiment showed that holes(h+),hydroxyl(∙OH)and superoxide(∙O2ˉ)radicals all took part in the MO degradation.In addition,the photocatalytic mechanism of straw@Fe_(3)O_(4)/Cu_(2)O was proposed based on the experimental results.After five cycles for the photodegradation of MO,the straw@Fe_(3)O_(4)/Cu_(2)O still displayed good photocatalytic activity,suggesting that the as-prepared composite had great potential for practical use in wastewater treatment.展开更多
Water splitting is important to the conversion and storage of renewable energy,but slow kinetics of the oxygen evolution reaction(OER)greatly limits its utility.Here,under visible light illumination,the p-n WO_(3)/SnS...Water splitting is important to the conversion and storage of renewable energy,but slow kinetics of the oxygen evolution reaction(OER)greatly limits its utility.Here,under visible light illumination,the p-n WO_(3)/SnSe_(2)(WS)heterojunction significantly activates OER catalysis of CoFe-layered double hydroxide(CF)/carbon nanotubes(CNTs).Specifically,the catalyst achieves an overpotential of 224 mV at 10 mA cm^(-2)and a small Tafel slope of 47 mV dec^(-1),superior to RuO_(2)and most previously reported transition metal-based OER catalysts.The p-n WS heterojunction shows strong light absorption to produce photogenerated carriers.The photogenerated holes are trapped by CF to suppresses the charge recombination and facilitate charge transfer,which accelerates OER kinetics and boost the activity for the OER.This work highlights the possibility of using heterojunctions to activate OER catalysis and advances the design of energy-efficient catalysts for water oxidation systems using solar energy.展开更多
The maximum velocity of a mobile vortex in movement is generally limited by the phenomenon of flux-flow instability(FFI),which necessitates weak vortex pinning and fast heat removal from non-equilibrium electrons.We h...The maximum velocity of a mobile vortex in movement is generally limited by the phenomenon of flux-flow instability(FFI),which necessitates weak vortex pinning and fast heat removal from non-equilibrium electrons.We here demonstrate exfoliations and nano-fabrications of Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ) crystalline nanostrips,which possess a rather weak pinning volume of vortices,relatively low resistivity,and large normal electron diffusion coefficient.The deduced vortex velocity in Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ) crystalline nanostrips can be up to 300 km/s near the superconducting transition temperature,well above the speed of sound.The observed vortex velocity is an order of magnitude faster than that of conventional superconducting systems,representing a perfect platform for exploration of ultra-fast vortex matter and a good candidate for fabrications of superconducting nanowire single photon detectors or superconducting THz modulator.展开更多
基金the financially support of the National Natural Science Foundation of China(12164051)the Joint Foundation of Provincial Science and Technology Department-Double First-class Construction of Yunnan University(2019FY003016)+4 种基金the Young Top Talent Project of Yunnan Province(YNWR-QNBJ-2018-229)the financially support by Yunnan Major Scientific and Technological Projects(202202AG050016)Advanced Analysis and Measurement Center of Yunnan University for the sample characterization service and the Postgraduate Research and Innovation Foundation of Yunnan University(2021Y036)the financially support of the National Natural Science Foundation of China(62064013)the Application Basic Research Project of Yunnan Province[2019FB130]。
文摘Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.
基金Science and Technology Project from Ministry of Housing and Urban-Rural Development of the People’s Republic of China(No.2014-K7-007)。
文摘Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and vibrating sample magnetometry,respectively.Photocatalytic performance of the straw@Fe_(3)O_(4)/Cu_(2)O was evaluated by measuring the degradation of methyl orange(MO)under irradiation of visible light.The introduction of Fe3O4 not only endowed the straw@Fe_(3)O_(4)/Cu_(2)O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs.The active species capture experiment showed that holes(h+),hydroxyl(∙OH)and superoxide(∙O2ˉ)radicals all took part in the MO degradation.In addition,the photocatalytic mechanism of straw@Fe_(3)O_(4)/Cu_(2)O was proposed based on the experimental results.After five cycles for the photodegradation of MO,the straw@Fe_(3)O_(4)/Cu_(2)O still displayed good photocatalytic activity,suggesting that the as-prepared composite had great potential for practical use in wastewater treatment.
基金the National Natural Science Foundation of China(No.41807213)the Hydrogeo-logical Survey Project of Huangshui River(No.DD20190331).
文摘Water splitting is important to the conversion and storage of renewable energy,but slow kinetics of the oxygen evolution reaction(OER)greatly limits its utility.Here,under visible light illumination,the p-n WO_(3)/SnSe_(2)(WS)heterojunction significantly activates OER catalysis of CoFe-layered double hydroxide(CF)/carbon nanotubes(CNTs).Specifically,the catalyst achieves an overpotential of 224 mV at 10 mA cm^(-2)and a small Tafel slope of 47 mV dec^(-1),superior to RuO_(2)and most previously reported transition metal-based OER catalysts.The p-n WS heterojunction shows strong light absorption to produce photogenerated carriers.The photogenerated holes are trapped by CF to suppresses the charge recombination and facilitate charge transfer,which accelerates OER kinetics and boost the activity for the OER.This work highlights the possibility of using heterojunctions to activate OER catalysis and advances the design of energy-efficient catalysts for water oxidation systems using solar energy.
基金supporting high quality of post growth treatment Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ)single crystalssupported by the National Key Research and Development Program of China(Grant No.2017YFA0304000)+4 种基金the National Natural Science Foundation of China(Grant Nos.61971408 and 61827823)Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)Shanghai Rising-Star Program(Grant No.20QA1410900)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant Nos.2020241 and 2021230)the Natural Science Foundation of Shanghai(Grant No.19ZR1467400)。
文摘The maximum velocity of a mobile vortex in movement is generally limited by the phenomenon of flux-flow instability(FFI),which necessitates weak vortex pinning and fast heat removal from non-equilibrium electrons.We here demonstrate exfoliations and nano-fabrications of Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ) crystalline nanostrips,which possess a rather weak pinning volume of vortices,relatively low resistivity,and large normal electron diffusion coefficient.The deduced vortex velocity in Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ) crystalline nanostrips can be up to 300 km/s near the superconducting transition temperature,well above the speed of sound.The observed vortex velocity is an order of magnitude faster than that of conventional superconducting systems,representing a perfect platform for exploration of ultra-fast vortex matter and a good candidate for fabrications of superconducting nanowire single photon detectors or superconducting THz modulator.
