All-inorganic Cs_(3)Bi_(2)I_(9)(CBI)halide perovskites are sought to be candidate for photoelectrical materials because of their low toxicity and satisfactory stability.Unfortunately,the discrete molecular[Bi2I9]3−clu...All-inorganic Cs_(3)Bi_(2)I_(9)(CBI)halide perovskites are sought to be candidate for photoelectrical materials because of their low toxicity and satisfactory stability.Unfortunately,the discrete molecular[Bi2I9]3−clusters limit the charge-transport behaviors.Herein,the defect halide perovskite based on trivalent Bi^(3+)is expanded to Cs_(3)Bi_(2)I_(6)Br_(3)(CBIB).Centimeter-size CBIB single crystal(Φ15×70 mm^(3))was grown by the vertical Bridgeman method.The powder X-ray diffraction analysis shows that CBIB has structure with lattice parameters of a=b=8.223Å,c=10.024Å,α=β=90°andγ=120°.The density functional theory(DFT)calculations demonstrate that the charge density distribution was enhanced after the dimensional expansion.The enhancement of carrier transport ability of(00l)in-plane is characterized before and after dimensional improvement.The obtained CBIB(001)exhibited an electron mobility up to 40.03 cm^(2)V^(−1)s^(−1)by time-of-flight(TOF)technique,higher than 26.46 cm^(2)V^(−1)s^(−1)of CBI(001).Furthermore,the X-ray sensitivity increases from 707.81μC Gy^(−1)cm^(−2)for CBI(001)to 3194.59μC Gy−1 cm^(−2)for CBIB(001).This research will deepen our understanding of Bi-based perovskite materials and afford more promising strategies for lead-free perovskite optoelectronic devices modification.展开更多
In this paper, 2201 and 2212 phases as the corresponding precursor of forming 2212 and 2223 phases are discussed,and the constructive process of unit cell of 2201 phase is ascertained by XRD and chemical kinetics me...In this paper, 2201 and 2212 phases as the corresponding precursor of forming 2212 and 2223 phases are discussed,and the constructive process of unit cell of 2201 phase is ascertained by XRD and chemical kinetics method. Subsequently, the process of 221展开更多
Six different compositions in Bi2Sr2Ca2Cu3Oy:Sex with x=0.0, 0.05, 0.1, 0.2, 0.3, 0.4 have been prepared by the solid state reaction method to explore doping of selenium in the system. Sintering at 847±4℃ and su...Six different compositions in Bi2Sr2Ca2Cu3Oy:Sex with x=0.0, 0.05, 0.1, 0.2, 0.3, 0.4 have been prepared by the solid state reaction method to explore doping of selenium in the system. Sintering at 847±4℃ and subsequent annealing at 827℃ has been carried out for different time periods. The samples have been characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and measurement of resistance below room temperature has been carried out by four-probe method. Superconducting transition temperature (Tc) value shows dependence on Se concentration: the highest Tc(0)=:94 K is observed for x=0.3. A detailed Auger electron spectroscopic (AES) analysis has been carried out to investigate the presence of Se in the grains of the superconductors. It has also been found that Se increases the Tc(0) value and promotes the formation of high temperature superconducting phase (2223), which coexists with low temperature phase (2212) in the sintered samples.展开更多
The positron annihilation lifetime and Doppler broadened line-shapeparameter have been measured between 77 and 300 K for Bi<sub>1.8</sub>Pb<sub>0.1</sub>Sb<sub>0.1</sub>Sr<sub>...The positron annihilation lifetime and Doppler broadened line-shapeparameter have been measured between 77 and 300 K for Bi<sub>1.8</sub>Pb<sub>0.1</sub>Sb<sub>0.1</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub>,Bi<sub>1.8</sub>Sb<sub>0.2</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub> and Bi<sub>1.7</sub>Pb<sub>0.2</sub>Sb<sub>0.1</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>2</sub>O<sub>x</sub>. The charge transfer from Cu-Olayers to Bi-O layers has been observed across T<sub>c</sub>s for all samples.Three samples allshow two normal state anomalies around 160 K and 240 K,respectively.The anomalyaround 160 K is attributed to the structural instability and that around 240 Kpresumably to the displacement phase transition.展开更多
Laying emphasis on the preparation of Bi based 2212 single phase superconducting powder, some technological parameters, which effect the single phase degree and uniformity of powder, such as prebaking, sintering and ...Laying emphasis on the preparation of Bi based 2212 single phase superconducting powder, some technological parameters, which effect the single phase degree and uniformity of powder, such as prebaking, sintering and heat treatment were investigated and discussed. Ensuring the powder T c at 83～85 K, the crucial impurity carbon was reduced to 0.03% and less. Adopting uncommon technique made the powder size to micrometer level, meanwhile the superconducting performance of the powder was unchanged. The fine superconducting powder was characterized. This process of Bi based 2212 superconducting powder was successful.展开更多
Electrocatalytic reduction of carbon dioxide(CO_(2))to valuable fuels is an up-and-coming approach.Owing to the low cost,environmental friendliness,and high selectivity to formate single product at low overpotentials,...Electrocatalytic reduction of carbon dioxide(CO_(2))to valuable fuels is an up-and-coming approach.Owing to the low cost,environmental friendliness,and high selectivity to formate single product at low overpotentials,bismuth(Bi)-based catalysts have attracted extensive research attention.In this review,the reaction mechanisms of Bi-based catalysts are first introduced,and the bimetallic Bi-based catalysts synthesized by alloying,doping,and loading strategies are reviewed from the aspects of catalyst component,morphology,synthesis procedure,and performance optimization for electrocatalytic CO_(2)reduction.We provide an in-depth discussion of the existing challenges and an outlook for this highly promising kind of electrocatalysis.展开更多
Since the discovery of Bi-base superconductors, investigations on their bonding and electronic configuration have been reported. Koniki et al. discussed the distribution and properties of Bi, Sr and Ca in crystal; Kih...Since the discovery of Bi-base superconductors, investigations on their bonding and electronic configuration have been reported. Koniki et al. discussed the distribution and properties of Bi, Sr and Ca in crystal; Kihida et al. pointed out that the binding energy E of Cu 2p<sup>3/2</sup> is unchanged in the Bi-Sr-Cu-O,（Bi,Pb）Sr-Cu-O,展开更多
Recently, systematic investigations on Bi-based superconductors were carried out by means of ultrasonic measurements, thermal analysis, specific heat experiments and X-ray diffraction measurements. It was found for th...Recently, systematic investigations on Bi-based superconductors were carried out by means of ultrasonic measurements, thermal analysis, specific heat experiments and X-ray diffraction measurements. It was found for the first time that a possible structural phase transition occurs near 210 K in these systems. All the samples used were of single phase展开更多
INTRODUCTIONIn order to improve the efficiency of the electrically small antenna, which has the physical extension smaller than the maximum free space wavelength transmitted or received, superconducting materials bega...INTRODUCTIONIn order to improve the efficiency of the electrically small antenna, which has the physical extension smaller than the maximum free space wavelength transmitted or received, superconducting materials began to be utilized in fabricating antennas since 1960s. In 1988, the Birmingham group of UK made for the first time the small dipole antennas展开更多
基金supported by the National Natural Science Foundations of China(Nos.51872228,U2032170 and 51802262)the National Key Research and Development Program of China(2016YFE0115200 and 2016YFF0101301)+2 种基金the Natural Science Foundations of Shaanxi Province(2019JQ-459 and 2020JC-12)the Natural Science Basic Research Plan in Shaanxi Province of China(2019ZDLGY04-07)the Fundamental Research Funds for the Central Universities(D5000210906 and 3102020QD0408)。
文摘All-inorganic Cs_(3)Bi_(2)I_(9)(CBI)halide perovskites are sought to be candidate for photoelectrical materials because of their low toxicity and satisfactory stability.Unfortunately,the discrete molecular[Bi2I9]3−clusters limit the charge-transport behaviors.Herein,the defect halide perovskite based on trivalent Bi^(3+)is expanded to Cs_(3)Bi_(2)I_(6)Br_(3)(CBIB).Centimeter-size CBIB single crystal(Φ15×70 mm^(3))was grown by the vertical Bridgeman method.The powder X-ray diffraction analysis shows that CBIB has structure with lattice parameters of a=b=8.223Å,c=10.024Å,α=β=90°andγ=120°.The density functional theory(DFT)calculations demonstrate that the charge density distribution was enhanced after the dimensional expansion.The enhancement of carrier transport ability of(00l)in-plane is characterized before and after dimensional improvement.The obtained CBIB(001)exhibited an electron mobility up to 40.03 cm^(2)V^(−1)s^(−1)by time-of-flight(TOF)technique,higher than 26.46 cm^(2)V^(−1)s^(−1)of CBI(001).Furthermore,the X-ray sensitivity increases from 707.81μC Gy^(−1)cm^(−2)for CBI(001)to 3194.59μC Gy−1 cm^(−2)for CBIB(001).This research will deepen our understanding of Bi-based perovskite materials and afford more promising strategies for lead-free perovskite optoelectronic devices modification.
文摘In this paper, 2201 and 2212 phases as the corresponding precursor of forming 2212 and 2223 phases are discussed,and the constructive process of unit cell of 2201 phase is ascertained by XRD and chemical kinetics method. Subsequently, the process of 221
文摘Six different compositions in Bi2Sr2Ca2Cu3Oy:Sex with x=0.0, 0.05, 0.1, 0.2, 0.3, 0.4 have been prepared by the solid state reaction method to explore doping of selenium in the system. Sintering at 847±4℃ and subsequent annealing at 827℃ has been carried out for different time periods. The samples have been characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and measurement of resistance below room temperature has been carried out by four-probe method. Superconducting transition temperature (Tc) value shows dependence on Se concentration: the highest Tc(0)=:94 K is observed for x=0.3. A detailed Auger electron spectroscopic (AES) analysis has been carried out to investigate the presence of Se in the grains of the superconductors. It has also been found that Se increases the Tc(0) value and promotes the formation of high temperature superconducting phase (2223), which coexists with low temperature phase (2212) in the sintered samples.
基金The project supported by IAEA under the Contract No.5295/RBby China National Nuclear Corporation.
文摘The positron annihilation lifetime and Doppler broadened line-shapeparameter have been measured between 77 and 300 K for Bi<sub>1.8</sub>Pb<sub>0.1</sub>Sb<sub>0.1</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub>,Bi<sub>1.8</sub>Sb<sub>0.2</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub> and Bi<sub>1.7</sub>Pb<sub>0.2</sub>Sb<sub>0.1</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>2</sub>O<sub>x</sub>. The charge transfer from Cu-Olayers to Bi-O layers has been observed across T<sub>c</sub>s for all samples.Three samples allshow two normal state anomalies around 160 K and 240 K,respectively.The anomalyaround 160 K is attributed to the structural instability and that around 240 Kpresumably to the displacement phase transition.
文摘Laying emphasis on the preparation of Bi based 2212 single phase superconducting powder, some technological parameters, which effect the single phase degree and uniformity of powder, such as prebaking, sintering and heat treatment were investigated and discussed. Ensuring the powder T c at 83～85 K, the crucial impurity carbon was reduced to 0.03% and less. Adopting uncommon technique made the powder size to micrometer level, meanwhile the superconducting performance of the powder was unchanged. The fine superconducting powder was characterized. This process of Bi based 2212 superconducting powder was successful.
基金This work was supported by the National Natural Science Foundation of China(grant nos.22178104,21838003,and 22008069)the Shanghai Scientific and Technological Innovation Project(grant no.22dz1205900)the Fundamental Research Funds for the Central Universities,and the Shanghai Sailing Program(grant no.20YF1410200).
文摘Electrocatalytic reduction of carbon dioxide(CO_(2))to valuable fuels is an up-and-coming approach.Owing to the low cost,environmental friendliness,and high selectivity to formate single product at low overpotentials,bismuth(Bi)-based catalysts have attracted extensive research attention.In this review,the reaction mechanisms of Bi-based catalysts are first introduced,and the bimetallic Bi-based catalysts synthesized by alloying,doping,and loading strategies are reviewed from the aspects of catalyst component,morphology,synthesis procedure,and performance optimization for electrocatalytic CO_(2)reduction.We provide an in-depth discussion of the existing challenges and an outlook for this highly promising kind of electrocatalysis.
文摘Since the discovery of Bi-base superconductors, investigations on their bonding and electronic configuration have been reported. Koniki et al. discussed the distribution and properties of Bi, Sr and Ca in crystal; Kihida et al. pointed out that the binding energy E of Cu 2p<sup>3/2</sup> is unchanged in the Bi-Sr-Cu-O,（Bi,Pb）Sr-Cu-O,
文摘Recently, systematic investigations on Bi-based superconductors were carried out by means of ultrasonic measurements, thermal analysis, specific heat experiments and X-ray diffraction measurements. It was found for the first time that a possible structural phase transition occurs near 210 K in these systems. All the samples used were of single phase
文摘INTRODUCTIONIn order to improve the efficiency of the electrically small antenna, which has the physical extension smaller than the maximum free space wavelength transmitted or received, superconducting materials began to be utilized in fabricating antennas since 1960s. In 1988, the Birmingham group of UK made for the first time the small dipole antennas
