Quantum dot(QD)-based infrared photodetector is a promising technology that can implement current monitoring,imaging and optical communication in the infrared region. However, the photodetection performance of self-po...Quantum dot(QD)-based infrared photodetector is a promising technology that can implement current monitoring,imaging and optical communication in the infrared region. However, the photodetection performance of self-powered QD devices is still limited by their unfavorable charge carrier dynamics due to their intrinsically discrete charge carrier transport process. Herein, we strategically constructed semiconducting matrix in QD film to achieve efficient charge transfer and extraction.The p-type semiconducting CuSCN was selected as energy-aligned matrix to match the n-type colloidal PbS QDs that was used as proof-of-concept. Note that the PbS QD/CuSCN matrix not only enables efficient charge carrier separation and transfer at nano-interfaces but also provides continuous charge carrier transport pathways that are different from the hoping process in neat QD film, resulting in improved charge mobility and derived collection efficiency. As a result, the target structure delivers high specific detectivity of 4.38 × 10^(12)Jones and responsivity of 782 mA/W at 808 nm, which is superior than that of the PbS QD-only photodetector(4.66 × 10^(11)Jones and 338 mA/W). This work provides a new structure candidate for efficient colloidal QD based optoelectronic devices.展开更多
Semiconducting single-walled carbon nanotubes(s-SWCNTs)with narrow diameters are promising for future applications in many fields,especially in nanoelectronics and optoelectronics.In this study,the oxygen vacancy conc...Semiconducting single-walled carbon nanotubes(s-SWCNTs)with narrow diameters are promising for future applications in many fields,especially in nanoelectronics and optoelectronics.In this study,the oxygen vacancy concentration modulating strategy was utilized for growing narrow diameters s-SWCNTs by the chemical vapor deposition(CVD)method.The Fe_(0.01)Mg_(0.99)O solid solution based catalyst was syn-thesized to anchor the Fe particles and inhibit aggregation for growing SWCNTs with uniform diameters.CeO_(2)was introduced into the catalyst to provide oxygen vacancies through H_(2)prereduction.These oxygen vacancies could form an oxidative environment during the growth of SWCNTs,and the chemically active metallic carbon nanotube caps are selectively etched away under this environment.The Fe/Ce molar ratio and H2 prereduction time were optimized to modulate the oxygen vacancy concentration.Ultimately,us-ing the Fe_(0.01)Mg_(0.99)O/CeO_(2)(3)catalyst with 10 min of H_(2)prereduction time,high purity s-SWCNTs with diameters ranging from 1.41 to 1.71 nm and a content of 95.1%were obtained with high selectivity and carbon yield(1.33 wt%).The mechanism behind this phenomenon was elucidated through experimental characterizations and first-principle simulations,further expanding the understanding of the growth of s-SWCNTs through the modulation of oxygen vacancy concentration.展开更多
INTRODUCTIONIn 1976, Alan MacDiarmid, Hideki Shirakawa and I, together with a talented group of graduate students andpost-doctoral researchers discovered conducting polymers and the ability to dope these polymers over...INTRODUCTIONIn 1976, Alan MacDiarmid, Hideki Shirakawa and I, together with a talented group of graduate students andpost-doctoral researchers discovered conducting polymers and the ability to dope these polymers over the fullrange from insulator to metal. This was particularly exciting because it created a new field of research on theboundary between chemistry and condensed matter physics, and because it created a number of opportunities:展开更多
Semiconducting conjugated polymer nanoparticles(SPNs)represent an emerging class of phototheranostic materi-als with great promise for cancer treatment.In this report,low-bandgap electron donoracceptor(DA)-conjugated ...Semiconducting conjugated polymer nanoparticles(SPNs)represent an emerging class of phototheranostic materi-als with great promise for cancer treatment.In this report,low-bandgap electron donoracceptor(DA)-conjugated SPNs with sur-face cloaked by red blood cell membrane(RBCM)are developed for highly e ective photoacoustic imaging and photothermal therapy.The resulting RBCM-coated SPN(SPN@RBCM)displays remarkable near-infrared light absorption and good photosta-bility,as well as high photothermal conver-sion e ciency for photoacoustic imaging and photothermal therapy.Particularly,due to the small size(<5 nm),SPN@RBCM has the advantages of deep tumor penetration and rapid clearance from the body with no appreciable toxicity.The RBCM endows the SPNs with prolonged systematic circulation time,less reticuloendothelial system uptake and reduced immune-recognition,hence improving tumor accumulation after intravenous injection,which provides strong photoacoustic signals and exerts excellent photothermal therapeutic e ects.Thus,this work provides a valuable paradigm for safe and highly e cient tumor pho-toacoustic imaging and photothermal therapy for further clinical translation.展开更多
An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and...An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and electronic properties measurements indicated the semconducting properties of the SWNTs samples. Simulant calculation indicated that S doping could induce convertion of metallic SWNTs into semiconducting ones. This strategy may pave a way for the direct synthesis of pure semiconducting SWNTs.展开更多
The effects of chloride ion on the electrochemical behavior and the semiconducting properties of the passive film on supermartensitic stainless steel in 0.5 mol/L NaHCO_3 solution were investigated using potentiodynam...The effects of chloride ion on the electrochemical behavior and the semiconducting properties of the passive film on supermartensitic stainless steel in 0.5 mol/L NaHCO_3 solution were investigated using potentiodynamic polarization, the potentiostatic current transients and Mott-Schottky analysis. The results indicated that chloride ion narrowed passivation region and improved pitting susceptibility. The steady state current densities were independent of film-formed potentials, which was in good agreement with the assumption of the point defect model （PDM）. The capacitance results showed the fact that the passive films had a multilayer character. The defect density decreased with increasing passive film formation potential. The chloride ion induced changes of the acceptor densities and donor densities of the passive films.展开更多
Chemoautotrophic organisms have once been excluded from the development of universally applicable CO2 fixation technology due to its low production yields of biomass. In this study, we used Acidithiobacillusferrooxida...Chemoautotrophic organisms have once been excluded from the development of universally applicable CO2 fixation technology due to its low production yields of biomass. In this study, we used Acidithiobacillusferrooxidans （A.f.） as a model chemoautotrophic microorganism to test the hypothesis that exogenetic photoelectrons from semiconducting mineral photocatalysis can enable the regeneration of Fe^2＋ that could be then used by A.f. and support its growth. In a simulated electrochemical system, where exogenetic electrons were provided by an electrochemical approach, an accelerated growth rate of A.f. was observed as compared with that in traditional batch cultivation. In a coupled system, where light-irradiated natural rutile provided the primary electron source to feed A.f., the bacterial growth rate as well as the subsequent CO2 fixation rate was demonstrated to be in a light-dependent manner. The sustaining flow of photogenerated electrons from semiconducting mineral to bacteria provided an inexhaustible electron source for chemoautotrophic bacteria growth and CO2 fixation. This finding might contribute to the development of novel effective CO2 fixation technology.展开更多
In recent years,Janus two-dimensional(2D)materials have received extensive research interests because of their outstanding electronic,mechanical,electromechanical,and optoelectronic properties.In this work,we explore ...In recent years,Janus two-dimensional(2D)materials have received extensive research interests because of their outstanding electronic,mechanical,electromechanical,and optoelectronic properties.In this work,we explore the structural,electromechanical,and optoelectronic properties of a novel hypothesized Janus InGaSSe monolayer by means of first-principles calculations.It is confirmed that the Janus InGaSSe monolayer indeed show extraordinary charge transport properties with intrinsic electron mobility of 48139 cm^(2)/(V·s)and hole mobility of 16311 cm^(2)/(V·s).Both uniaxial and biaxial strains can effectively tune its electronic property.Moreover,the Janus InGaSSe monolayer possesses excellent piezoelectric property along both inplane and out-of-plane directions.The results of this work imply that the Janus InGaSSe monolayer is in fact an efficient photocatalyst candidate,and may provide useful guidelines for the discovery of other new 2D photocatalytic and piezoelectric materials.展开更多
We investigate theoretically Rabi-like splitting and Fano resonance in absorption spectra of quantum dots(QDs)based on a hybrid QD-semiconducting nanowire/superconductor(SNW/SC)device mediated by Majorana fermions(MFs...We investigate theoretically Rabi-like splitting and Fano resonance in absorption spectra of quantum dots(QDs)based on a hybrid QD-semiconducting nanowire/superconductor(SNW/SC)device mediated by Majorana fermions(MFs).Under the condition of pump on-resonance and off-resonance,the absorption spectrum experiences the conversion from Fano resonance to Rabi-like splitting in different parametric regimes.In addition,the Fano resonances are accompanied by the rapid normal phase dispersion,which will indicate the coherent optical propagation.The results indicate that the group velocity index is tunable with controlling the interaction between the QD and MFs,which can reach the conversion between the fast-and slow-light.Fano resonance will be another method to detect MFs and our research may indicate prospective applications in quantum information processing based on the hybrid QD-SNW/SC devices.展开更多
This perspective paper introduces the concept that nanocarbons and related materials such as carbon dots are an interesting intrinsic photocatalytic semiconducting material, and not only a modifier of the existing (se...This perspective paper introduces the concept that nanocarbons and related materials such as carbon dots are an interesting intrinsic photocatalytic semiconducting material, and not only a modifier of the existing (semiconducting) materials to prepare hybrid materials. The semiconducting properties of the nanocarbons, and the possibility to have the band gap within the visible-light region through defect band engineering, introduction of light heteroatoms and control/manipulation of the curvature or surface functionalization are discussed. These materials are conceptually different from the 'classical' semiconducting photocatalysts, because semiconductor domains with tuneable characteristics are embedded in a conductive carbon matrix, with the presence of various functional groups (as C=0 groups) enhancing charge separation by trapping electrons. These nanocarbons open a range of new possibilities for photocatalysis both for energetic and environmental applications. The use of nanocarbons as quantum dots and photo luminescent materials was also analysed. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
The anti——icing and de·-icing methods of insulator strings are still under laboratory studies while many technologies are applied in operation to overhead conductors.The anti—icing method using semiconducting ...The anti——icing and de·-icing methods of insulator strings are still under laboratory studies while many technologies are applied in operation to overhead conductors.The anti—icing method using semiconducting silicone rubber coating applied to the bottom side of the insulators could get good results in a climate chamber.However,the resistance of the coating is an important factor influencing the anti—icing performance of the coated insulators.Thus the coating resistance should be determined.展开更多
The modulation of bandgap and HOCO/LUCO energies of conjugated polymers by copolymerization or by incorporation of electron withdrawing/releasing groups is studied.The study was conducted by band structure calculation...The modulation of bandgap and HOCO/LUCO energies of conjugated polymers by copolymerization or by incorporation of electron withdrawing/releasing groups is studied.The study was conducted by band structure calculation applying density functional theory with generalized gradient approximation.The polymers and copolymers were modeled as 1D infinite system with periodical boundary condition along the molecular direction.It is concluded that the bandgap and HOCO/LUCO energies of conjugated polymers depend on both electron withdrawing/releasing effects and non-bonding interaction between a side group and the conjugated systems.展开更多
H_(2) is considered an indispensable component of the atmosphere for the growth of high-quality singlewall carbon nanotubes(SWCNTs)by chemical vapor deposition.However,details of the roles H_(2) playing are still uncl...H_(2) is considered an indispensable component of the atmosphere for the growth of high-quality singlewall carbon nanotubes(SWCNTs)by chemical vapor deposition.However,details of the roles H_(2) playing are still unclear due to the complex conditions of SWCNT growth.In this study,we elucidate the functions of H_(2) in the selective growth of semiconducting SWCNTs(s-SWCNTs)by using monodispersed uniform Fe nanoparticles as a catalyst.High-quality s-SWCNTs were synthesized by finely tuning the concentration of H_(2) and the other growth parameters.Experimental data combined with atomistic simulations indicate that H_(2) not only adjusts the concentration of the carbon source,but also serves as a mild etchant that selectively removes small carbon caps grown by a perpendicular mode from the Fe nanoparticles.These results provide useful hints for the controlled growth of SWCNTs with a semiconducting or metallic conductivity,and even a specific chirality.展开更多
We predicted two stable two-dimensional materials of carbon and bismuth elements,namely BiC and Bi_(2)C monolayers.The stabilities of two monolayers were examined by cohesive energy,Born criteria,first-principle MD si...We predicted two stable two-dimensional materials of carbon and bismuth elements,namely BiC and Bi_(2)C monolayers.The stabilities of two monolayers were examined by cohesive energy,Born criteria,first-principle MD simulations and phonon spectra,respectively.By including the spin-orbit coupling effects,the BiC monolayer is a metal and the Bi_(2)C monolayer possesses a narrow direct(indirect)band gap of 0.403(0.126)eV under the HSE06(GGA-PBE)functional.For the adsorption of CO_(2)molecules,the BiC and Bi_(2)C monolayers have three stable adsorption sites C2,T3 and T4 with the adsorption energies as-0.57,-0.51 and-0.81 eV,and the activation ability on the adsorption as T4>T3>C2.These consequences make the BiC and Bi_(2)C monolayers to be promising adsorbents to capture CO_(2)gas,the Bi_(2)C monolayer to be well photovoltaics and optoelectronics material,and the BiC monolayer to be ideal battery and electronics materials,respectively.展开更多
Using particle swarm optimization(PSO)methodology for crystal structure prediction,we predicted a novel two-dimensional(2 D)monolayer of silicide diphosphorus compound:SiP_(2),which exhibits good stability as examined...Using particle swarm optimization(PSO)methodology for crystal structure prediction,we predicted a novel two-dimensional(2 D)monolayer of silicide diphosphorus compound:SiP_(2),which exhibits good stability as examined via cohesive energy,mechanical criteria,molecular dynamics simulation and all positive phonon spectrum,respectively.The SiP_(2)monolayer is an indirect semiconductor with the band gap as 1.8484 eV(PBE)or 2.681 eV(HSE06),which makes it more advantageous for high-frequencyresponse optoelectronic materials.Moreover,the monolayer is a relatively hard auxetic material with negative Possion’s ratios,and also possesses a ultrahigh carrier mobility(1.069×10^(5)cm^(2)V^(-1)s^(-1))which is approximately four times the maximum value in phosphorene and comparable to the value of graphene and CP monolayers.Furthermore,the effects of strains on band structures and optical properties of SiP_(2)monolayer have been studied,as well as CO_(2)molecules can be strongly chemically adsorbed on the SiP_(2)monolayer.A semiconductor-to-metal transition for-9.5%strain ratio case and a huge optical absorption capacity on the order of 10^(6)cm^(-1)in visible region present.These theoretical findings endow SiP_(2)Monolayer to be a novel 2 D material holding great promises for applications in highperformance electronics,optoelectronics,mechanics and CO_(2)capturing material.展开更多
The title compound was prepared and characterized.Its crystal Structure was determined by X—ray diffraction analysis,and consists of segregated cation and an- ion stacks in the perpendicular directions.Crystal data:m...The title compound was prepared and characterized.Its crystal Structure was determined by X—ray diffraction analysis,and consists of segregated cation and an- ion stacks in the perpendicular directions.Crystal data:monoclinic,P2_1/c,Mr=765.21, a=7.882(2)b=15.526(4),c=13.736(2)β=99.87(2)~0,V=1656.0(6)~3,Ac =1.53g/cm^3,Z=2,F(000)=780,R=0.040 and R_w=0.056.展开更多
Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize se...Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize semiconducting Cu_(2)Se by direct selenization of Cu(111).Scanning tunneling microcopy measurements combined with first-principles calculations allow us to determine the structural and electronic properties of the obtained structure.X-ray photoelectron spectroscopy data reveal chemical composition of the sample,which is Cu_(2)Se.The observed moire pattern indicates a lattice mismatch between Cu_(2)Se and the underlying Cu(111)-√3×√3 surface.Differential conductivity obtained by scanning tunneling spectroscopy demonstrates that the synthesized Cu_(2)Se exhibits a band gap of 0.78 eV.Furthermore,the calculated density of states and band structure demonstrate that the isolated Cu_(2)Se is a semiconductor with an indirect band gap of-0.8 eV,which agrees quite well with the experimental results.Our study provides a simple pathway varying toward the synthesis of novel layered 2D transition chalcogenides materials.展开更多
The ac impedance of Nb-doped semicon-ducting (Bao.72Pbo.28)TiO3 ceramics implanted with copper ions(200keV,6X1015 and 1X1017 ions/cm2) in the temperature range 25-320C and the frequency range 10 Hz -13MHz was measured...The ac impedance of Nb-doped semicon-ducting (Bao.72Pbo.28)TiO3 ceramics implanted with copper ions(200keV,6X1015 and 1X1017 ions/cm2) in the temperature range 25-320C and the frequency range 10 Hz -13MHz was measured. According to the change of impedance spectroscopy and the equivalent circuit model of semiconducting(Ba, Pb)TiO3 ceramics, the dependence of resistance of bulk and grain-boundary on temperature was analyzed. The results show that relatively low dose must be used to increase the magnitude of the positive temperature coeffieient of resistance(PTCR)effects in the cermmics. In addition,the effects of Cu ion implantation on the PTCR behavior of the ceramics was studied by raststance-tempera-ture measurement.展开更多
A new polymeric iodoplumbate complex [Zn（DMF）6][Pb2I6] 1 has been prepared and characterized by elemental analysis and single-crystal X-ray analysis. Its structure contains infinite iodoplumbate chains constructed b...A new polymeric iodoplumbate complex [Zn（DMF）6][Pb2I6] 1 has been prepared and characterized by elemental analysis and single-crystal X-ray analysis. Its structure contains infinite iodoplumbate chains constructed by the [PbI5] subunit. EHT crystal orbital calculation and the experimental results show that this material is an unconventional semiconductor and the electrical character is associated with its structural feature.展开更多
Fe-doped In2O3 dilute magnetic semiconducting nanowires are fabricated on A u-deposited Si substrates by the chemical vapor deposition technique. It is confirmed by energy dispersive x-ray spectroscopy （EDS）, x-ray ...Fe-doped In2O3 dilute magnetic semiconducting nanowires are fabricated on A u-deposited Si substrates by the chemical vapor deposition technique. It is confirmed by energy dispersive x-ray spectroscopy （EDS）, x-ray photoelectron spectroscopy （XPS） and Raman spectroscopy that Fe has been successfully doped into lattices of In2O3 nanowires. The EDS measurements reveal a large amount of oxygen vacancies existing in the Fe-doped In2O3 nanowires. The Fe dopant exists as a mixture of Fe2＋ and Fe3＋, as revealed by the XPS. The origin of room-temperature ferromagnetism in Fe-doped In2O3 nanowires is explained by the bound magnetic polaron model.展开更多
基金supported by the National Natural Science Foundation of China (No. 62204079)the Science and Technology Development Project of Henan Province (Nos.202300410048, 202300410057)+2 种基金the China Postdoctoral Science Foundation (No. 2022M711037)the Intelligence Introduction Plan of Henan Province in 2021 (No. CXJD2021008)Henan University Fund。
文摘Quantum dot(QD)-based infrared photodetector is a promising technology that can implement current monitoring,imaging and optical communication in the infrared region. However, the photodetection performance of self-powered QD devices is still limited by their unfavorable charge carrier dynamics due to their intrinsically discrete charge carrier transport process. Herein, we strategically constructed semiconducting matrix in QD film to achieve efficient charge transfer and extraction.The p-type semiconducting CuSCN was selected as energy-aligned matrix to match the n-type colloidal PbS QDs that was used as proof-of-concept. Note that the PbS QD/CuSCN matrix not only enables efficient charge carrier separation and transfer at nano-interfaces but also provides continuous charge carrier transport pathways that are different from the hoping process in neat QD film, resulting in improved charge mobility and derived collection efficiency. As a result, the target structure delivers high specific detectivity of 4.38 × 10^(12)Jones and responsivity of 782 mA/W at 808 nm, which is superior than that of the PbS QD-only photodetector(4.66 × 10^(11)Jones and 338 mA/W). This work provides a new structure candidate for efficient colloidal QD based optoelectronic devices.
基金supported by the National Natural Science Foun-dation of China(Nos.51872231 and 51672221)the Key Indus-trial Chain Project of Shaanxi Province,China(No.2018ZDCXL-GY-08-07).
文摘Semiconducting single-walled carbon nanotubes(s-SWCNTs)with narrow diameters are promising for future applications in many fields,especially in nanoelectronics and optoelectronics.In this study,the oxygen vacancy concentration modulating strategy was utilized for growing narrow diameters s-SWCNTs by the chemical vapor deposition(CVD)method.The Fe_(0.01)Mg_(0.99)O solid solution based catalyst was syn-thesized to anchor the Fe particles and inhibit aggregation for growing SWCNTs with uniform diameters.CeO_(2)was introduced into the catalyst to provide oxygen vacancies through H_(2)prereduction.These oxygen vacancies could form an oxidative environment during the growth of SWCNTs,and the chemically active metallic carbon nanotube caps are selectively etched away under this environment.The Fe/Ce molar ratio and H2 prereduction time were optimized to modulate the oxygen vacancy concentration.Ultimately,us-ing the Fe_(0.01)Mg_(0.99)O/CeO_(2)(3)catalyst with 10 min of H_(2)prereduction time,high purity s-SWCNTs with diameters ranging from 1.41 to 1.71 nm and a content of 95.1%were obtained with high selectivity and carbon yield(1.33 wt%).The mechanism behind this phenomenon was elucidated through experimental characterizations and first-principle simulations,further expanding the understanding of the growth of s-SWCNTs through the modulation of oxygen vacancy concentration.
基金The copyright of this paper is owned by the Nobel Foundation.
文摘INTRODUCTIONIn 1976, Alan MacDiarmid, Hideki Shirakawa and I, together with a talented group of graduate students andpost-doctoral researchers discovered conducting polymers and the ability to dope these polymers over the fullrange from insulator to metal. This was particularly exciting because it created a new field of research on theboundary between chemistry and condensed matter physics, and because it created a number of opportunities:
基金supported by the National Natural Science Foundation of China(Grant Nos.61727823,51873160)the joint research project of Health and Education Commission of Fujian Province(Grant No.2019-WJ-20).
文摘Semiconducting conjugated polymer nanoparticles(SPNs)represent an emerging class of phototheranostic materi-als with great promise for cancer treatment.In this report,low-bandgap electron donoracceptor(DA)-conjugated SPNs with sur-face cloaked by red blood cell membrane(RBCM)are developed for highly e ective photoacoustic imaging and photothermal therapy.The resulting RBCM-coated SPN(SPN@RBCM)displays remarkable near-infrared light absorption and good photosta-bility,as well as high photothermal conver-sion e ciency for photoacoustic imaging and photothermal therapy.Particularly,due to the small size(<5 nm),SPN@RBCM has the advantages of deep tumor penetration and rapid clearance from the body with no appreciable toxicity.The RBCM endows the SPNs with prolonged systematic circulation time,less reticuloendothelial system uptake and reduced immune-recognition,hence improving tumor accumulation after intravenous injection,which provides strong photoacoustic signals and exerts excellent photothermal therapeutic e ects.Thus,this work provides a valuable paradigm for safe and highly e cient tumor pho-toacoustic imaging and photothermal therapy for further clinical translation.
基金supported by National Natural Science Foundation of China No.50730008Shanghai Science and Technology Grant No.0752nm015National Basic Research Program of China No.2006CB300406
文摘An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and electronic properties measurements indicated the semconducting properties of the SWNTs samples. Simulant calculation indicated that S doping could induce convertion of metallic SWNTs into semiconducting ones. This strategy may pave a way for the direct synthesis of pure semiconducting SWNTs.
文摘The effects of chloride ion on the electrochemical behavior and the semiconducting properties of the passive film on supermartensitic stainless steel in 0.5 mol/L NaHCO_3 solution were investigated using potentiodynamic polarization, the potentiostatic current transients and Mott-Schottky analysis. The results indicated that chloride ion narrowed passivation region and improved pitting susceptibility. The steady state current densities were independent of film-formed potentials, which was in good agreement with the assumption of the point defect model （PDM）. The capacitance results showed the fact that the passive films had a multilayer character. The defect density decreased with increasing passive film formation potential. The chloride ion induced changes of the acceptor densities and donor densities of the passive films.
基金supported by the Key Project of the National Natural Science Foundation of China (Grant No. 41230103)the National Natural Science Foundation of China (Grant No. 41272003)
文摘Chemoautotrophic organisms have once been excluded from the development of universally applicable CO2 fixation technology due to its low production yields of biomass. In this study, we used Acidithiobacillusferrooxidans （A.f.） as a model chemoautotrophic microorganism to test the hypothesis that exogenetic photoelectrons from semiconducting mineral photocatalysis can enable the regeneration of Fe^2＋ that could be then used by A.f. and support its growth. In a simulated electrochemical system, where exogenetic electrons were provided by an electrochemical approach, an accelerated growth rate of A.f. was observed as compared with that in traditional batch cultivation. In a coupled system, where light-irradiated natural rutile provided the primary electron source to feed A.f., the bacterial growth rate as well as the subsequent CO2 fixation rate was demonstrated to be in a light-dependent manner. The sustaining flow of photogenerated electrons from semiconducting mineral to bacteria provided an inexhaustible electron source for chemoautotrophic bacteria growth and CO2 fixation. This finding might contribute to the development of novel effective CO2 fixation technology.
基金supported by the Fundamental Research Funds for the Central Universities of China(Nos.PA2021KCPY0029 and LEM21A01)。
文摘In recent years,Janus two-dimensional(2D)materials have received extensive research interests because of their outstanding electronic,mechanical,electromechanical,and optoelectronic properties.In this work,we explore the structural,electromechanical,and optoelectronic properties of a novel hypothesized Janus InGaSSe monolayer by means of first-principles calculations.It is confirmed that the Janus InGaSSe monolayer indeed show extraordinary charge transport properties with intrinsic electron mobility of 48139 cm^(2)/(V·s)and hole mobility of 16311 cm^(2)/(V·s).Both uniaxial and biaxial strains can effectively tune its electronic property.Moreover,the Janus InGaSSe monolayer possesses excellent piezoelectric property along both inplane and out-of-plane directions.The results of this work imply that the Janus InGaSSe monolayer is in fact an efficient photocatalyst candidate,and may provide useful guidelines for the discovery of other new 2D photocatalytic and piezoelectric materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.11804004 and 11647001)the China Postdoctoral Science Foundation(Grant No.2020M681973)Anhui Provincial Natural Science Foundation,China(Grant No.1708085QA11)。
文摘We investigate theoretically Rabi-like splitting and Fano resonance in absorption spectra of quantum dots(QDs)based on a hybrid QD-semiconducting nanowire/superconductor(SNW/SC)device mediated by Majorana fermions(MFs).Under the condition of pump on-resonance and off-resonance,the absorption spectrum experiences the conversion from Fano resonance to Rabi-like splitting in different parametric regimes.In addition,the Fano resonances are accompanied by the rapid normal phase dispersion,which will indicate the coherent optical propagation.The results indicate that the group velocity index is tunable with controlling the interaction between the QD and MFs,which can reach the conversion between the fast-and slow-light.Fano resonance will be another method to detect MFs and our research may indicate prospective applications in quantum information processing based on the hybrid QD-SNW/SC devices.
基金Financial support from the Italian MIUR gh the PRIN Project 2015K7FZLH SMARTNESS "Solar driven chemistry:new materials for photo- and electro-catalysis"SINCHEM,a Joint Doctorate programme selected under the Erasmus Mundus Action 1 Programme (FPA 2013-0037)
文摘This perspective paper introduces the concept that nanocarbons and related materials such as carbon dots are an interesting intrinsic photocatalytic semiconducting material, and not only a modifier of the existing (semiconducting) materials to prepare hybrid materials. The semiconducting properties of the nanocarbons, and the possibility to have the band gap within the visible-light region through defect band engineering, introduction of light heteroatoms and control/manipulation of the curvature or surface functionalization are discussed. These materials are conceptually different from the 'classical' semiconducting photocatalysts, because semiconductor domains with tuneable characteristics are embedded in a conductive carbon matrix, with the presence of various functional groups (as C=0 groups) enhancing charge separation by trapping electrons. These nanocarbons open a range of new possibilities for photocatalysis both for energetic and environmental applications. The use of nanocarbons as quantum dots and photo luminescent materials was also analysed. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
文摘The anti——icing and de·-icing methods of insulator strings are still under laboratory studies while many technologies are applied in operation to overhead conductors.The anti—icing method using semiconducting silicone rubber coating applied to the bottom side of the insulators could get good results in a climate chamber.However,the resistance of the coating is an important factor influencing the anti—icing performance of the coated insulators.Thus the coating resistance should be determined.
基金Supported by the Department of Education of Shanghai(No.A10-0101-06-425).
文摘The modulation of bandgap and HOCO/LUCO energies of conjugated polymers by copolymerization or by incorporation of electron withdrawing/releasing groups is studied.The study was conducted by band structure calculation applying density functional theory with generalized gradient approximation.The polymers and copolymers were modeled as 1D infinite system with periodical boundary condition along the molecular direction.It is concluded that the bandgap and HOCO/LUCO energies of conjugated polymers depend on both electron withdrawing/releasing effects and non-bonding interaction between a side group and the conjugated systems.
基金the Ministry of Science and Technology of China(No.2016YFA0200101)the National Natural Science Foundation of China(Nos.51702325,51625203,51532008,51521091,51572264 and 5171101360)。
文摘H_(2) is considered an indispensable component of the atmosphere for the growth of high-quality singlewall carbon nanotubes(SWCNTs)by chemical vapor deposition.However,details of the roles H_(2) playing are still unclear due to the complex conditions of SWCNT growth.In this study,we elucidate the functions of H_(2) in the selective growth of semiconducting SWCNTs(s-SWCNTs)by using monodispersed uniform Fe nanoparticles as a catalyst.High-quality s-SWCNTs were synthesized by finely tuning the concentration of H_(2) and the other growth parameters.Experimental data combined with atomistic simulations indicate that H_(2) not only adjusts the concentration of the carbon source,but also serves as a mild etchant that selectively removes small carbon caps grown by a perpendicular mode from the Fe nanoparticles.These results provide useful hints for the controlled growth of SWCNTs with a semiconducting or metallic conductivity,and even a specific chirality.
基金funded by the Natural Science Foundation of China(Nos.21603109,11304128)the Henan Joint Fund of the National Natural Science Foundation of China(No.U1404216)+1 种基金the Science and Technology Program of Henan Department of Science and Technology,China(No.182102310609)the Construct Program of Applied Characteristic Discipline in Hunan University of Science and Engineering(Mathematics,Education and Electronic Science and Technology).
文摘We predicted two stable two-dimensional materials of carbon and bismuth elements,namely BiC and Bi_(2)C monolayers.The stabilities of two monolayers were examined by cohesive energy,Born criteria,first-principle MD simulations and phonon spectra,respectively.By including the spin-orbit coupling effects,the BiC monolayer is a metal and the Bi_(2)C monolayer possesses a narrow direct(indirect)band gap of 0.403(0.126)eV under the HSE06(GGA-PBE)functional.For the adsorption of CO_(2)molecules,the BiC and Bi_(2)C monolayers have three stable adsorption sites C2,T3 and T4 with the adsorption energies as-0.57,-0.51 and-0.81 eV,and the activation ability on the adsorption as T4>T3>C2.These consequences make the BiC and Bi_(2)C monolayers to be promising adsorbents to capture CO_(2)gas,the Bi_(2)C monolayer to be well photovoltaics and optoelectronics material,and the BiC monolayer to be ideal battery and electronics materials,respectively.
基金funded by the Scientific Research Fund of Hunan Provincial Education Department of China(No.16A081)the Natural Science Foundation of China(Nos.21603109,11304128)+2 种基金the Henan Joint Fund of the National Natural Science Foundation of China(No.U1404216)the Science and Technology Program of Henan Department of Science and Technology,China(No.182102310609)the Construct Program of Applied Characteristic Discipline in Hunan University of Science and Engineering(Mathematics,Electronic Science and Technology)。
文摘Using particle swarm optimization(PSO)methodology for crystal structure prediction,we predicted a novel two-dimensional(2 D)monolayer of silicide diphosphorus compound:SiP_(2),which exhibits good stability as examined via cohesive energy,mechanical criteria,molecular dynamics simulation and all positive phonon spectrum,respectively.The SiP_(2)monolayer is an indirect semiconductor with the band gap as 1.8484 eV(PBE)or 2.681 eV(HSE06),which makes it more advantageous for high-frequencyresponse optoelectronic materials.Moreover,the monolayer is a relatively hard auxetic material with negative Possion’s ratios,and also possesses a ultrahigh carrier mobility(1.069×10^(5)cm^(2)V^(-1)s^(-1))which is approximately four times the maximum value in phosphorene and comparable to the value of graphene and CP monolayers.Furthermore,the effects of strains on band structures and optical properties of SiP_(2)monolayer have been studied,as well as CO_(2)molecules can be strongly chemically adsorbed on the SiP_(2)monolayer.A semiconductor-to-metal transition for-9.5%strain ratio case and a huge optical absorption capacity on the order of 10^(6)cm^(-1)in visible region present.These theoretical findings endow SiP_(2)Monolayer to be a novel 2 D material holding great promises for applications in highperformance electronics,optoelectronics,mechanics and CO_(2)capturing material.
文摘The title compound was prepared and characterized.Its crystal Structure was determined by X—ray diffraction analysis,and consists of segregated cation and an- ion stacks in the perpendicular directions.Crystal data:monoclinic,P2_1/c,Mr=765.21, a=7.882(2)b=15.526(4),c=13.736(2)β=99.87(2)~0,V=1656.0(6)~3,Ac =1.53g/cm^3,Z=2,F(000)=780,R=0.040 and R_w=0.056.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51772087,11904094,51972106,and 11804089)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000)Natural Science Foundation of Hunan Province,China(Grant Nos.2019JJ50034 and 2019JJ50073).
文摘Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize semiconducting Cu_(2)Se by direct selenization of Cu(111).Scanning tunneling microcopy measurements combined with first-principles calculations allow us to determine the structural and electronic properties of the obtained structure.X-ray photoelectron spectroscopy data reveal chemical composition of the sample,which is Cu_(2)Se.The observed moire pattern indicates a lattice mismatch between Cu_(2)Se and the underlying Cu(111)-√3×√3 surface.Differential conductivity obtained by scanning tunneling spectroscopy demonstrates that the synthesized Cu_(2)Se exhibits a band gap of 0.78 eV.Furthermore,the calculated density of states and band structure demonstrate that the isolated Cu_(2)Se is a semiconductor with an indirect band gap of-0.8 eV,which agrees quite well with the experimental results.Our study provides a simple pathway varying toward the synthesis of novel layered 2D transition chalcogenides materials.
文摘The ac impedance of Nb-doped semicon-ducting (Bao.72Pbo.28)TiO3 ceramics implanted with copper ions(200keV,6X1015 and 1X1017 ions/cm2) in the temperature range 25-320C and the frequency range 10 Hz -13MHz was measured. According to the change of impedance spectroscopy and the equivalent circuit model of semiconducting(Ba, Pb)TiO3 ceramics, the dependence of resistance of bulk and grain-boundary on temperature was analyzed. The results show that relatively low dose must be used to increase the magnitude of the positive temperature coeffieient of resistance(PTCR)effects in the cermmics. In addition,the effects of Cu ion implantation on the PTCR behavior of the ceramics was studied by raststance-tempera-ture measurement.
基金supported by the NNSFC (21053001, 20701014)Fundamental Research Funds for the Central Universities (2009ZM0030 and student program)Undergraduate Research program of Guangdong
文摘A new polymeric iodoplumbate complex [Zn（DMF）6][Pb2I6] 1 has been prepared and characterized by elemental analysis and single-crystal X-ray analysis. Its structure contains infinite iodoplumbate chains constructed by the [PbI5] subunit. EHT crystal orbital calculation and the experimental results show that this material is an unconventional semiconductor and the electrical character is associated with its structural feature.
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB921101,2014CB921103 and2013CB922103the National Natural Science Foundation of China under Grant Nos 11274003,61176088 and 61274102+1 种基金the Program for the New Century Excellent Talents in University under Grant No NCET-11-0240the PAPD Project,and the Fundamental Research Funds for the Central Universities
文摘Fe-doped In2O3 dilute magnetic semiconducting nanowires are fabricated on A u-deposited Si substrates by the chemical vapor deposition technique. It is confirmed by energy dispersive x-ray spectroscopy （EDS）, x-ray photoelectron spectroscopy （XPS） and Raman spectroscopy that Fe has been successfully doped into lattices of In2O3 nanowires. The EDS measurements reveal a large amount of oxygen vacancies existing in the Fe-doped In2O3 nanowires. The Fe dopant exists as a mixture of Fe2＋ and Fe3＋, as revealed by the XPS. The origin of room-temperature ferromagnetism in Fe-doped In2O3 nanowires is explained by the bound magnetic polaron model.
