Y3Al5O12:Ce3+ is the most famous phosphor material due to its excellent photolumincent properties.Here,through first-principles calculation,the effect of carbon interstitial defects on Y3Al5O12:Ce3+phosphor was invest...Y3Al5O12:Ce3+ is the most famous phosphor material due to its excellent photolumincent properties.Here,through first-principles calculation,the effect of carbon interstitial defects on Y3Al5O12:Ce3+phosphor was investigated. It is found that the carbon interstitials tend to occupy the next-nearest sites of Ce3+ion in Y3Al5O12:Ce3+ lattice. Specially,these interstitial defects can shorten the Ce3+-O2-bond length, leading to a larger crystal field splitting of 5 d orbital of the Ce3+atom and bigger 5 d centroid shift.These two factors cause the emission spectrum of Y3Al5O12(C):Ce3+red shift compared with that of Y3Al5O12:Ce3+. Moreover, with our comparison experiment, we find that the Y3Al5O12(C):Ce3+ has an obvious red shift compared with that of Y3Al5O12:Ce3+system,which is in accord with our first principles calculation. Our work systematically investigates the impact of the carbon interstitial defect on Y3Al5O12:Ce3+,and provides a new route to tune the emission spectrum in Y3Al5O12:Ce3+.展开更多
A novel ZnII-based metal-organic framework with the formula of{[Zn_(2)(BBIP)_(2)(NDC)_(2)]·H_(2)O}n(JXUST-5)derived from 3,5-bis(benzimidazol-1-yl)pyridine(BBIP)and 1,4-naphthalenedicarboxylic acid(H_(2)NDC)has b...A novel ZnII-based metal-organic framework with the formula of{[Zn_(2)(BBIP)_(2)(NDC)_(2)]·H_(2)O}n(JXUST-5)derived from 3,5-bis(benzimidazol-1-yl)pyridine(BBIP)and 1,4-naphthalenedicarboxylic acid(H_(2)NDC)has been synthesized.The adjacent Zn^(II)ions are linked through two BBIP ligands to form a[Zn_(2)(BBIP)_(2)]secondary building unit(SBU).The neighbouring SBUs are further connected by NDC^(2-)withμ2-η^(1):η^(1)andμ2-η^(1):η^(1):η^(1)bridging modes to form a two-dimensional(2D)framework.Topological analysis shows that JXUST-5 could be simplified as an uninodal fes topology with a point symbol of{4.8^(2)}.Furthermore,the 2D framework net could be extended through C-H···πinteraction to form the three-dimensional supramolecular structure.Luminescent experiments suggest that JXUST-5 could selectively and sensitively recognize Al^(3+)and Ga^(3+)through fluorescence enhancement effect along with a relatively large red shift.The detection limits for Al^(3+)and Ga^(3+)are 0.17 and 0.69 ppm,respectively.Interestingly,the sensing process for both Al^(3+)and Ga^(3+)could be directly observed with naked eyes under 365 nm UV lamp.Notably,JXUST-5 could be recycled at least five times as a fluorescent sensor toward Al^(3+)and Ga^(3+),which is the second example of turn-on MOF based fluorescent sensor toward Ga^(3+).展开更多
The characteristics of backward harmonic radiation due to electron oscillations driven by a linearly polarized fs laser pulse are analysed considering a single electron model. The spectral distributions of the electro...The characteristics of backward harmonic radiation due to electron oscillations driven by a linearly polarized fs laser pulse are analysed considering a single electron model. The spectral distributions of the electron＇s backward harmonic radiation are investigated in detail for different parameters of the driver laser pulse. Higher order harmonic radiations are possible for a sufficiently intense driving laser pulse. We have shown that for a realistic pulsed photon beam, the spectrum of the radiation is red shifted as well as broadened because of changes in the longitudinal velocity of the electrons during the laser pulse. These effects are more pronounced at higher laser intensities giving rise to higher order harmonics that eventually leads to a continuous spectrum. Numerical simulations have further shown that by increasing the laser pulse width the broadening of the high harmonic radiations can be controlled.展开更多
There is a stable?cosmic background photon gas fulfilled in our universe and a very weak damping force is acting on every traveling photon, then the light red shift has been observed at a large distance. When a photon...There is a stable?cosmic background photon gas fulfilled in our universe and a very weak damping force is acting on every traveling photon, then the light red shift has been observed at a large distance. When a photon travels in the cosmic background photon gas, its frequency continually lowers and at last diminishes in the photon gas as a low velocity one. The decay factor of traveling photons has been estimated;the light red shift is nonlinear in space, and our visual field is finite although the universe is infinite.展开更多
Using Weierstrassian elliptic functions the exact geodesics in the Schwarzschild metric are expressed in a simple and most transparent form. The results are useful for analytical and numerical applications. For exampl...Using Weierstrassian elliptic functions the exact geodesics in the Schwarzschild metric are expressed in a simple and most transparent form. The results are useful for analytical and numerical applications. For example we calculate the perihelion precession and the light deflection in the post-Einsteinian approximation. The bounded orbits are computed in the post-Newtonian order. As a topical application we calculate the gravitational red shift for a star moving in the Schwarzschild field.展开更多
A theoretical study on the red-shift of laser-induced electro-absorption is presented. It is found that laser-induced red-shift scales with the cube root of the pump laser intensity in the optical tunneling regime and...A theoretical study on the red-shift of laser-induced electro-absorption is presented. It is found that laser-induced red-shift scales with the cube root of the pump laser intensity in the optical tunneling regime and has an obvious deviation from this scale in the multi-photon regime. Our results show that in the optical tunneling regime, the laser-induced red shift has the same law as that in the direct current （DC） approximation. Though the scales are the same in the optical tunneling regime, the physical pictures in the two cases are quite different. The electro-absorption in the DC case is a tunneling-assisted transition process, while the laser-induced electro-absorption is a mixed multi-photon process.展开更多
In this work we present a study of a new method to prove the equation of the gravitational red shift of spec-tral lines. That’s according to the generalized special relativity theory. The equation of the gravitationa...In this work we present a study of a new method to prove the equation of the gravitational red shift of spec-tral lines. That’s according to the generalized special relativity theory. The equation of the gravitational red shift of spectral lines has been studied in many different works, using different methods depending on the Newtonian mechanics, and other theories. Although attention was drawn to the fact that the well-known ex-pression of the gravitational Red-Shift of spectral lines may be derived with no recourse to the general rela-tivity theory! In this study a unique derivation has been done using the Generalized Special Relativity (GSR) and the same result obtained.展开更多
In this work, we presented a fluorescent probe(MCQ-DNBS) for selective and sensitive detection of biothiols based on a methylated chromenoquinoline(MCQ) derivative. Probe MCQ-DNBS was constructed by masking the OH gro...In this work, we presented a fluorescent probe(MCQ-DNBS) for selective and sensitive detection of biothiols based on a methylated chromenoquinoline(MCQ) derivative. Probe MCQ-DNBS was constructed by masking the OH group in MCQ with a common sensing unit, 2,4-dinitrobezensulfonate group(DNBS) for biothiols. Due to the photo-induced electron transfer(PET) process between MCQ and DNBS, this probe was weekly fluorescent. Upon the addition of biothiols(Cys, Hcy and GSH), this probe emitted a strong red fluorescence(λ_(em max)=613 nm) with a large Stokes shift(115 nm). In addition,fluorescence imaging of biothiols in living cells was successfully realized using MCQ-DNBS as a detector.展开更多
HR (Huairou) 89065 (Boulder 5395 )(N33, L260 )in March, 1989 was a very powerful solar active region. There occurred the most violent activities in the recent ten years or more, including the largest sunspots, continu...HR (Huairou) 89065 (Boulder 5395 )(N33, L260 )in March, 1989 was a very powerful solar active region. There occurred the most violent activities in the recent ten years or more, including the largest sunspots, continuous large solar flares, X-ray events and展开更多
The harmonic condition is applied to the motion of galaxies in relativistic cosmologyunder the approximation that the Universe is an empty de Sitter universe, while the galaxiesmove radially as particles along their g...The harmonic condition is applied to the motion of galaxies in relativistic cosmologyunder the approximation that the Universe is an empty de Sitter universe, while the galaxiesmove radially as particles along their geodesics in this universe without interfering with each other gravitationally. Transformations of the coordinates between the co-moving, the de Sitter and the standard systems of coordinates are given. The Poynting vector giving the intensity of light emitted by the distant receding galaxy and observed on earth has different forms in these systems of coordinates. As a first approximation the velocitydistance relation is the same in all of them. But for higher approximations there are differences which can only be verified by future more refined and accurate astronomical observations. It is shown that the velocity-distance relation depends upon the number of stars in the receding galaxy or upon its mass. Hence according to the present analysis motions of the galaxies in the universe are isotroplc, but the distribution of matter is not necesssarily homogeneous.展开更多
Mimicking animal skin is an effective strategy for enhancing the performance of artificial skin.Inspired by a chameleon’s iridophore and a spider’s slit organ,a novel photonic-electronic skin(PE-skin)with excellent ...Mimicking animal skin is an effective strategy for enhancing the performance of artificial skin.Inspired by a chameleon’s iridophore and a spider’s slit organ,a novel photonic-electronic skin(PE-skin)with excellent optical/electrical dual-sensing performance was developed by integrating a photonic crystal(PC)with a conductive MXene/silver nanowire(AgNW)composite into adhesive polydimethylsiloxane.The PC layer containing in-plane-spaced and interplane-packed nanoparticle arrays was fabricated via a fast,facile,combined method of“Marangoni self-assembly”,“plasma etching”,and“adhesive PDMS transfer”.Notably,the PC exhibited a red-shift mechanochromic response through in-plane stretching,which is the first report of sharing the same mechanochromic behavior as a chameleon iridophore.The underlying MXene layer formed slit-organ-like cracks that provided high sensitivity,whereas the AgNWs maintained their conductivity under large strains.The resultant PE-skin exhibited a high mechanochromic sensitivity(2.57 nm%−1)and a high electrical gauge factor of 2600 in a large strain-sensing range(up to 85%).These advantages have been confirmed in the detection of full-range human motions,such as speech recognition,using a deep neural network algorithm.The red-shift stretchable PC demonstrates a new paradigm for artificial chameleon skins,and the bionic PC crack bilayer structure extends the design concept for visually interactive e-skins.展开更多
The typical aza-BODIPYs in the dye family are known for bright fluorescence,excellent stability,and tunable absorption wavelengths.Hence,these dyes are attracting the increasing attention.Aza-BODIPYs having the maxima...The typical aza-BODIPYs in the dye family are known for bright fluorescence,excellent stability,and tunable absorption wavelengths.Hence,these dyes are attracting the increasing attention.Aza-BODIPYs having the maxima absorption in the near-infrared(NIR)region(650-900 nm)are very favorable for bioimaging in vivo due to the less photo-damage,deeper tissue penetration,and less interference from background auto-fluorescence by biomolecules in the living systems.Many strategies have been employed to modify the structures of the aza-BODIPY core to provide the NIR absorbing dyes.Among these,the most effective method is the fusion of the aromatic rings in aza-BODIPY system.This review allsidedly summarizes the recent development of ring-fused aza-BODIPY dyes(λ_(abs)>700 nm)focusing on the design,synthesis,and potential applications in the NIR region since 2002.展开更多
We have obtained vertically aligned ZnO nanowire arrays synthesized by microwave-assisted heating method with different growth time.From the room-temperature PL measurement,the strong deep-level emission and weak near...We have obtained vertically aligned ZnO nanowire arrays synthesized by microwave-assisted heating method with different growth time.From the room-temperature PL measurement,the strong deep-level emission and weak near band edge(NBE)emission can be seen.The deep-level emissions became weaker and deep-level emissions became stronger when the samples were annealed at 300℃for 30 min,meanwhile,the NBE emission peaks get red-shifted with growth time,and the longer the growth time,the more the peak shifting.This phenomenon can be attributed that the diameter of ZnO nanowires increases with growth time.This PL emission phenomenon is important in research of optoelectronic application.展开更多
In this work,Bi2Te3 films（250 nm） are fabricated on Si O2/Si substrates by radio frequency（RF） magnetron sputtering at room temperature,and the prepared films are annealed over the temperature range of 200 °C...In this work,Bi2Te3 films（250 nm） are fabricated on Si O2/Si substrates by radio frequency（RF） magnetron sputtering at room temperature,and the prepared films are annealed over the temperature range of 200 °C to 400 °C.Crystallinity and electrical properties of the films can be tuned correspondingly.The power factors of Bi2Te3 films of 0.85 μW/K2 cm to 11.43 μW/K2 cm were achieved after annealing.The infrared reflectance measurements from 2.5 μm to 5.0 μm demonstrate that there is also a slight red-shift of the plasma oscillation frequency in the Bi2Te3 films.By means of plasmonic calculations,we attribute the red-shift of absorption peaks to the reduction of carrier concentration and the change of effective mass of Bi2Te3 films with the increased annealing temperature.展开更多
Two novel thieno-[3,4-b]-pyrazine-based molecules, TP-E and TP-O, were designed and synthesized for potential application as red fluorescent emitters. The bulky tetraphenylethylene groups were attached at the peripher...Two novel thieno-[3,4-b]-pyrazine-based molecules, TP-E and TP-O, were designed and synthesized for potential application as red fluorescent emitters. The bulky tetraphenylethylene groups were attached at the periphery of the thieno-[3,4-b]-pyrazine core to form the non-planar molecules, as efficient solid- state emitting materials. The peripheral groups were grafted to the emissive core through either a conjugated acetylene bond, or a non-conjugated ether bond. These molecules exhibit strnng red fluorescence in both dilute solutions and in thin films with large Stokes shifts of over 100 nm. The cyclic voltammetry measurements showed the reversible oxidation and reduction behavior for both compounds. All these properties indicate the two compounds are possible functional materials for use in ontoelectronic devices.展开更多
基金Project supported by the National Basic Research Program of China(2014CB643801)
文摘Y3Al5O12:Ce3+ is the most famous phosphor material due to its excellent photolumincent properties.Here,through first-principles calculation,the effect of carbon interstitial defects on Y3Al5O12:Ce3+phosphor was investigated. It is found that the carbon interstitials tend to occupy the next-nearest sites of Ce3+ion in Y3Al5O12:Ce3+ lattice. Specially,these interstitial defects can shorten the Ce3+-O2-bond length, leading to a larger crystal field splitting of 5 d orbital of the Ce3+atom and bigger 5 d centroid shift.These two factors cause the emission spectrum of Y3Al5O12(C):Ce3+red shift compared with that of Y3Al5O12:Ce3+. Moreover, with our comparison experiment, we find that the Y3Al5O12(C):Ce3+ has an obvious red shift compared with that of Y3Al5O12:Ce3+system,which is in accord with our first principles calculation. Our work systematically investigates the impact of the carbon interstitial defect on Y3Al5O12:Ce3+,and provides a new route to tune the emission spectrum in Y3Al5O12:Ce3+.
基金supported from the National Natural Science Foundation of China(Nos.22061019,21761012 and 21861018)the Natural Science Foundation of Jiangxi Province(Nos.20192BAB203001,20202ACBL213001,20192ACBL20013 and 20182BCB22010)+1 种基金the Youth Jinggang Scholars Program in Jiangxi Province(No.QNJG2019053)the Two Thousand Talents Program in Jiangxi Province(No.jxsq2019201068)。
文摘A novel ZnII-based metal-organic framework with the formula of{[Zn_(2)(BBIP)_(2)(NDC)_(2)]·H_(2)O}n(JXUST-5)derived from 3,5-bis(benzimidazol-1-yl)pyridine(BBIP)and 1,4-naphthalenedicarboxylic acid(H_(2)NDC)has been synthesized.The adjacent Zn^(II)ions are linked through two BBIP ligands to form a[Zn_(2)(BBIP)_(2)]secondary building unit(SBU).The neighbouring SBUs are further connected by NDC^(2-)withμ2-η^(1):η^(1)andμ2-η^(1):η^(1):η^(1)bridging modes to form a two-dimensional(2D)framework.Topological analysis shows that JXUST-5 could be simplified as an uninodal fes topology with a point symbol of{4.8^(2)}.Furthermore,the 2D framework net could be extended through C-H···πinteraction to form the three-dimensional supramolecular structure.Luminescent experiments suggest that JXUST-5 could selectively and sensitively recognize Al^(3+)and Ga^(3+)through fluorescence enhancement effect along with a relatively large red shift.The detection limits for Al^(3+)and Ga^(3+)are 0.17 and 0.69 ppm,respectively.Interestingly,the sensing process for both Al^(3+)and Ga^(3+)could be directly observed with naked eyes under 365 nm UV lamp.Notably,JXUST-5 could be recycled at least five times as a fluorescent sensor toward Al^(3+)and Ga^(3+),which is the second example of turn-on MOF based fluorescent sensor toward Ga^(3+).
基金supported by the National High-Tech ICF Committee of China (No.10335020/A0506)National Natural Science Foundation of China (Nos.10474081 and 10576035)Shanghai Natural Science Foundation (No.05ZR14159)
文摘The characteristics of backward harmonic radiation due to electron oscillations driven by a linearly polarized fs laser pulse are analysed considering a single electron model. The spectral distributions of the electron＇s backward harmonic radiation are investigated in detail for different parameters of the driver laser pulse. Higher order harmonic radiations are possible for a sufficiently intense driving laser pulse. We have shown that for a realistic pulsed photon beam, the spectrum of the radiation is red shifted as well as broadened because of changes in the longitudinal velocity of the electrons during the laser pulse. These effects are more pronounced at higher laser intensities giving rise to higher order harmonics that eventually leads to a continuous spectrum. Numerical simulations have further shown that by increasing the laser pulse width the broadening of the high harmonic radiations can be controlled.
文摘There is a stable?cosmic background photon gas fulfilled in our universe and a very weak damping force is acting on every traveling photon, then the light red shift has been observed at a large distance. When a photon travels in the cosmic background photon gas, its frequency continually lowers and at last diminishes in the photon gas as a low velocity one. The decay factor of traveling photons has been estimated;the light red shift is nonlinear in space, and our visual field is finite although the universe is infinite.
文摘Using Weierstrassian elliptic functions the exact geodesics in the Schwarzschild metric are expressed in a simple and most transparent form. The results are useful for analytical and numerical applications. For example we calculate the perihelion precession and the light deflection in the post-Einsteinian approximation. The bounded orbits are computed in the post-Newtonian order. As a topical application we calculate the gravitational red shift for a star moving in the Schwarzschild field.
基金Project supported by the Fundamental Research Funds for the Central Universities,China (Grant No.A735496)the National Natural Science Foundation of China (Grant No.61178018)the Ph.D. Funding Support Program of the Education Ministry of China (Grant No.20110185110007)
文摘A theoretical study on the red-shift of laser-induced electro-absorption is presented. It is found that laser-induced red-shift scales with the cube root of the pump laser intensity in the optical tunneling regime and has an obvious deviation from this scale in the multi-photon regime. Our results show that in the optical tunneling regime, the laser-induced red shift has the same law as that in the direct current （DC） approximation. Though the scales are the same in the optical tunneling regime, the physical pictures in the two cases are quite different. The electro-absorption in the DC case is a tunneling-assisted transition process, while the laser-induced electro-absorption is a mixed multi-photon process.
文摘In this work we present a study of a new method to prove the equation of the gravitational red shift of spec-tral lines. That’s according to the generalized special relativity theory. The equation of the gravitational red shift of spectral lines has been studied in many different works, using different methods depending on the Newtonian mechanics, and other theories. Although attention was drawn to the fact that the well-known ex-pression of the gravitational Red-Shift of spectral lines may be derived with no recourse to the general rela-tivity theory! In this study a unique derivation has been done using the Generalized Special Relativity (GSR) and the same result obtained.
基金supported by the National Natural Science Foundation of China (No.U1608222)Special Fund for Agroscientific Research in the Public Interest of China(No.201503108)+1 种基金Fundamental Research Funds for the Central Universities of Central South University (No. 2018zzts109)the State Key Laboratory of Chemo/Biosensing and Chemometrics (No. 2016005)
文摘In this work, we presented a fluorescent probe(MCQ-DNBS) for selective and sensitive detection of biothiols based on a methylated chromenoquinoline(MCQ) derivative. Probe MCQ-DNBS was constructed by masking the OH group in MCQ with a common sensing unit, 2,4-dinitrobezensulfonate group(DNBS) for biothiols. Due to the photo-induced electron transfer(PET) process between MCQ and DNBS, this probe was weekly fluorescent. Upon the addition of biothiols(Cys, Hcy and GSH), this probe emitted a strong red fluorescence(λ_(em max)=613 nm) with a large Stokes shift(115 nm). In addition,fluorescence imaging of biothiols in living cells was successfully realized using MCQ-DNBS as a detector.
基金Project supported by the National Natural Science Foundation of China.
文摘HR (Huairou) 89065 (Boulder 5395 )(N33, L260 )in March, 1989 was a very powerful solar active region. There occurred the most violent activities in the recent ten years or more, including the largest sunspots, continuous large solar flares, X-ray events and
文摘The harmonic condition is applied to the motion of galaxies in relativistic cosmologyunder the approximation that the Universe is an empty de Sitter universe, while the galaxiesmove radially as particles along their geodesics in this universe without interfering with each other gravitationally. Transformations of the coordinates between the co-moving, the de Sitter and the standard systems of coordinates are given. The Poynting vector giving the intensity of light emitted by the distant receding galaxy and observed on earth has different forms in these systems of coordinates. As a first approximation the velocitydistance relation is the same in all of them. But for higher approximations there are differences which can only be verified by future more refined and accurate astronomical observations. It is shown that the velocity-distance relation depends upon the number of stars in the receding galaxy or upon its mass. Hence according to the present analysis motions of the galaxies in the universe are isotroplc, but the distribution of matter is not necesssarily homogeneous.
基金supported by the Basic and Applied Basic Research Foundation of Guangdong province(2024A1515030155,2022A1515010272,2024A1515012609,2022A1515140055,2023A1515011459,2022A1515011671,2022A1515140055)Natural Science Foundation of China(61904067,62475101,62175094,62275109)+1 种基金Knowledge Innovation Program of Wuhan-Basi Research(2023020201010183)Guangzhou-Jinan University Municipal and University Joint Funding Programs(202201020045).
文摘Mimicking animal skin is an effective strategy for enhancing the performance of artificial skin.Inspired by a chameleon’s iridophore and a spider’s slit organ,a novel photonic-electronic skin(PE-skin)with excellent optical/electrical dual-sensing performance was developed by integrating a photonic crystal(PC)with a conductive MXene/silver nanowire(AgNW)composite into adhesive polydimethylsiloxane.The PC layer containing in-plane-spaced and interplane-packed nanoparticle arrays was fabricated via a fast,facile,combined method of“Marangoni self-assembly”,“plasma etching”,and“adhesive PDMS transfer”.Notably,the PC exhibited a red-shift mechanochromic response through in-plane stretching,which is the first report of sharing the same mechanochromic behavior as a chameleon iridophore.The underlying MXene layer formed slit-organ-like cracks that provided high sensitivity,whereas the AgNWs maintained their conductivity under large strains.The resultant PE-skin exhibited a high mechanochromic sensitivity(2.57 nm%−1)and a high electrical gauge factor of 2600 in a large strain-sensing range(up to 85%).These advantages have been confirmed in the detection of full-range human motions,such as speech recognition,using a deep neural network algorithm.The red-shift stretchable PC demonstrates a new paradigm for artificial chameleon skins,and the bionic PC crack bilayer structure extends the design concept for visually interactive e-skins.
基金supported by the National Natural Science Foundation of China(Nos.22078201,U1908202)“Chunhui Program”cooperative research project of Education Ministry+2 种基金Liaoning BaiQianWan Talents ProgramServing local project of Education Department of Liaoning Province(No.LZ2020005)the Distinguished Professor Project Liaoning Province(No.20183532)。
文摘The typical aza-BODIPYs in the dye family are known for bright fluorescence,excellent stability,and tunable absorption wavelengths.Hence,these dyes are attracting the increasing attention.Aza-BODIPYs having the maxima absorption in the near-infrared(NIR)region(650-900 nm)are very favorable for bioimaging in vivo due to the less photo-damage,deeper tissue penetration,and less interference from background auto-fluorescence by biomolecules in the living systems.Many strategies have been employed to modify the structures of the aza-BODIPY core to provide the NIR absorbing dyes.Among these,the most effective method is the fusion of the aromatic rings in aza-BODIPY system.This review allsidedly summarizes the recent development of ring-fused aza-BODIPY dyes(λ_(abs)>700 nm)focusing on the design,synthesis,and potential applications in the NIR region since 2002.
基金by the National Natural Science Foundation of China(Nos.61874058 and 51861145301)the Nanjing University of Posts and Telecommunications under Research Projects(Nos.NY220036 and NY217096)the Nanjing University of Posts and Telecommunications Foundation(Nos.JUH219002 and JUH219007)。
文摘We have obtained vertically aligned ZnO nanowire arrays synthesized by microwave-assisted heating method with different growth time.From the room-temperature PL measurement,the strong deep-level emission and weak near band edge(NBE)emission can be seen.The deep-level emissions became weaker and deep-level emissions became stronger when the samples were annealed at 300℃for 30 min,meanwhile,the NBE emission peaks get red-shifted with growth time,and the longer the growth time,the more the peak shifting.This phenomenon can be attributed that the diameter of ZnO nanowires increases with growth time.This PL emission phenomenon is important in research of optoelectronic application.
基金supported by the National Natural Science Foundation of China under Grant No.51025208Program for Changjiang Scholars and Innovative Research Team in University under Grant No.IRT1309
文摘In this work,Bi2Te3 films（250 nm） are fabricated on Si O2/Si substrates by radio frequency（RF） magnetron sputtering at room temperature,and the prepared films are annealed over the temperature range of 200 °C to 400 °C.Crystallinity and electrical properties of the films can be tuned correspondingly.The power factors of Bi2Te3 films of 0.85 μW/K2 cm to 11.43 μW/K2 cm were achieved after annealing.The infrared reflectance measurements from 2.5 μm to 5.0 μm demonstrate that there is also a slight red-shift of the plasma oscillation frequency in the Bi2Te3 films.By means of plasmonic calculations,we attribute the red-shift of absorption peaks to the reduction of carrier concentration and the change of effective mass of Bi2Te3 films with the increased annealing temperature.
基金the National Natural Science Foundation of China(Nos.21274016 and 21072026)Fundamental Research Funds for the Central Universities(No.DUT13LK06)for financial support to this work
文摘Two novel thieno-[3,4-b]-pyrazine-based molecules, TP-E and TP-O, were designed and synthesized for potential application as red fluorescent emitters. The bulky tetraphenylethylene groups were attached at the periphery of the thieno-[3,4-b]-pyrazine core to form the non-planar molecules, as efficient solid- state emitting materials. The peripheral groups were grafted to the emissive core through either a conjugated acetylene bond, or a non-conjugated ether bond. These molecules exhibit strnng red fluorescence in both dilute solutions and in thin films with large Stokes shifts of over 100 nm. The cyclic voltammetry measurements showed the reversible oxidation and reduction behavior for both compounds. All these properties indicate the two compounds are possible functional materials for use in ontoelectronic devices.
