Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(...Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(+)-Eu^(3+)codoped Cs_(2)NaInCl_(6)nanocrystals were investigated.The pe rovskite nanocrystals exhibit a broad warm-white photo luminescence with correlated color temperature(CCT)of 3447 K and color rendering index(CRI)of 90.2,and the means of codoping would improve its optical performance.A fast energy transfer and a long-lived self-trapped excitons state are unveiled by the femtosecond transient absorption spectra.The fast energy transfer from the self-trapped excitons of host nanocrystals to the Eu^(3+)ions is helpful to achieve a broad photoluminescence,and the quantum yield of Cs_(2)NaInCl_(6):0.05Ag^(+)-Eu^(3+)anocrystals can be enha nced to 69.5%.There is a large exciton binding energy and strong electron-phonon interaction in the codoped perovskite nanocrystals.The efficient and excellent air-stable double perovskite nanocrystals would be considered as a single-component phosphor for warm-white lighting.展开更多
Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i...Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.展开更多
Pore size and distribution in carbon-based materials are regarded to be a key factor to affect the electrochemical capacitive performances of the resultant electrodes.In this study,nitrogen and oxygen codoped porous c...Pore size and distribution in carbon-based materials are regarded to be a key factor to affect the electrochemical capacitive performances of the resultant electrodes.In this study,nitrogen and oxygen codoped porous carbons(NOPCs) are fabricated based on a simple Schiff-base reaction between m-phenylenediamine and terephthalaldehyde.The NOPCs have tunable morphologies,high surface areas,abundant heteroatom doping.More importantly,the carbons show a dominant micropores of 0.5-0.8 nm,comparable to the ionic sizes of LiTFSI(Li^+0.069 nm;TFSI-0.79 nm) water-in-salt electrolyte with a high potential window of 2.2 V.Consequently,the fabricated symmetric supercapacitor gives a high energy output of 30.5 Wh/kg at 1 kW/kg,and high stability after successive 10,000 cycles with ^96.8% retention.This study provides promising potential to develop high-energy supercapacitors.展开更多
Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxi...Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxiety is the poor affinity toward polar polysulfides due to the intrinsic nonpolar surface of carbon.Herein, we report a direct pyrolysis of the mixture urea and boric acid to synthesize B/N–codoped hierarchically porous carbon nanosheets(B–N–CSs) as efficient sulfur host for lithium–sulfur battery. The graphene–like B–N–CSs provides high specific surface area and porous structure with abundant micropores(1.1 nm) and low–range mesopores(2.3 nm), thereby constraining the sulfur active materials within the pores. More importantly, the codoped B/N elements can further enhance the polysulfide confinement through strong Li–N and B–S interaction based on the Lewis acid–base theory. These structural superiorities significantly suppress the shuttle effect by both physical confinement and chemical interaction, and promote the redox kinetics of polysulfide conversion. When evaluated as the cathode host, the S/B–N–CSs composite displays the excellent performance with a high reversible capacity up to 772 m A h g–1 at 0.5 C and a low fading rate of ^0.09% per cycle averaged upon 500 cycles. In particular, remarkable stability with a high capacity retention of 87.1% can be realized when augmenting the sulfur loading in the cathode up to 4.6 mg cm^(-2).展开更多
Simultaneous elimination of As(Ⅲ) and Pb(Ⅱ) from wastewater is still a great challenge.In this work,an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the rem...Simultaneous elimination of As(Ⅲ) and Pb(Ⅱ) from wastewater is still a great challenge.In this work,an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the remediate the co-pollution of As(Ⅲ) and Pb(Ⅱ).The positive enthalpy indicated that the adsorption in As-Pb co-pollution was an endothermic reaction.The mechanism of As(Ⅲ) removal could be illustrated by surface complexation,oxidation and precipitation.In addition to precipitation and complexation,the elimination mechanism of Pb(Ⅱ) also contained ion exchange and electrostatic interactions.Competitive and synergistic effects existed simultaneously in the co-contamination system.The suppression of As(Ⅲ) was ascribed to competitive complexation of the two metals on Fe/S-BC,while the synergy of Pb(Ⅱ) was attributed to the formation of the PbFe2(AsO_(4))2(OH)2.Batch experiments revealed that Fe/S-BC had outstanding ability to remove As(Ⅲ) and Pb(Ⅱ),regardless of pH dependency and interference by various coexisting ions.The maximum adsorption capacities of the Fe/S-BC for As(Ⅲ) and Pb(Ⅱ) were 91.2 mg/g and 631.7 mg/g,respectively.Fe/S-BC could be treated as a novel candidate for the elimination of As(Ⅲ)-Pb(Ⅱ) combined pollution.展开更多
Intense 1-5 μm infrared emission from near-to mid-infrared was obtained from Ho3+/Yb3+codoped TeO2-ZnF2 oxyfluorotellurite glasses which were prepared by melt-quenching method under the 980 nm LD excitation,and the e...Intense 1-5 μm infrared emission from near-to mid-infrared was obtained from Ho3+/Yb3+codoped TeO2-ZnF2 oxyfluorotellurite glasses which were prepared by melt-quenching method under the 980 nm LD excitation,and the emission intensity can be enhanced with the increase of ZnF2 content.Judd-Ofelt analysis was used to evaluate the radiative transition parameters of the excited levels according to the absorption spectra.The stimulated emission cross section of 5 I6→5 I8(1.2 μm),5 I7→5 I8(2.0μm),5 I6→5 I7(2.85 μm) and 5 I5→5 I6(4.0 μm) transitions were calculated to reach 0.639 × 10-20,0.760 ×10-20,0.985×10 20 and 0.484 × 10-20 cm2,respectively.The energy transfer coefficients(CDA) are enhanced with the increase of ZnF2 content and phonon contribution ratios of phonon assisted energy transfer process between Ho3+ and Yb3+were figured out.Our results demonstrate that these TeO2-ZnF2 glasses,which possess good thermal stability and transparency,low phonon energy(about 600 cm-1),excellent near-and mid-infrared emission in the range of 1-5 μm wavelength,would be promising material for infrared optical fibers and infrared lasers.展开更多
Er3+/Yb3+-codoped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared and spectroscopic properties of rare earth ions were investigated. Fluoride nanocrystals Ba2GdF7 were...Er3+/Yb3+-codoped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared and spectroscopic properties of rare earth ions were investigated. Fluoride nanocrystals Ba2GdF7 were successfully precipitated in glass matrix, which was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) results. In comparison with the as-made precursor, significant enhancement of upconversion luminescence was observed in the Er3+/Yb3+ codoped oxyfluoride glass ceramics, which may be due to the variation of coordination environment around Er3+ and Yb3+ ions after crystallization. The transition mechanisms of the green and red upconversion luminescence were ascribed to a two-photon process, and that of the blue upconversion luminescence was a three-photon process.展开更多
Novel oxyfluoride glasses are developed with the composition of 30SiO2-15Al2O3-28PbF2-22CdF2-0.1TmF3 - xYbF3 - （4.9 - x） AlF3（x=0, 0.5, 1.0, 1.5, 2.0） in tool fraction, Furthermore, the upconversion luminescence c...Novel oxyfluoride glasses are developed with the composition of 30SiO2-15Al2O3-28PbF2-22CdF2-0.1TmF3 - xYbF3 - （4.9 - x） AlF3（x=0, 0.5, 1.0, 1.5, 2.0） in tool fraction, Furthermore, the upconversion luminescence characteristics under a 970nm excitation are investigated. Intense blue, red and near infrared luminescences peaked at 453nm, 476nm, 647nm and 789nm, which correspond to the transitions of Tm^3＋： ^1D2 →^3F4, ^1G4 →^3H6, ^1G4 →^3F4, and ^3H4 →^3H6, respectively, are observed. Due to the sensitization of Yb^3＋ ions, all the upconversion luminescence intensities are enhanced considerably with Yb^3＋ concentration increasing. The upconversion mechanisms are discussed based on the energy matching rule and quadratic dependence on excitation power. The results indicate that the dominant mechanism is the excited state absorption for those upconversion emissions.展开更多
Effects of growth temperature on the structural and electrical properties of Li-N-H codoped ZnO thin films grown by DC reactive magnetron sputtering were investigated. Scanning electron microscopy and X-ray diffractio...Effects of growth temperature on the structural and electrical properties of Li-N-H codoped ZnO thin films grown by DC reactive magnetron sputtering were investigated. Scanning electron microscopy and X-ray diffraction results showed that increasing growth temperature could improve the crystalline quality. But Hall measurement results showed that growth temperature had a nonlinear influence on the electrical property. The variation of electrical properties with the growth temperature was found to be related to the activated concentration of N in ZnO and the evaporation of Li during the growth process, derived from the Hall measurement and the second ion mass spectroscopy measurement.展开更多
The electronic structures and magnetic properties of the Cu and N codoped 3C-Si C system have been investigated by the first-principles calculation.The results show that the Cu doped Si C system prefers the anti-ferro...The electronic structures and magnetic properties of the Cu and N codoped 3C-Si C system have been investigated by the first-principles calculation.The results show that the Cu doped Si C system prefers the anti-ferromagnetic（AFM） state.Compared to the Cu doped system,the ionicities of C–Cu and C–Si in Cu and N codoped Si C are respectively enhanced and weakened.Especially,the Cu and N codoped Si C systems favor the ferromagnetic（FM） coupling.The FM interactions can be explained by virtual hopping.However,higher N concentration will weaken the ferromagnetism.In order to keep the FM interaction,the N concentration should be restricted within 9.3% according to our analysis.展开更多
NS codoped carbon nanorods（NS-CNRs） were prepared using crab shell as template and polyphenylene sulfide（PPS） as both the C and S precursor, followed by carbonization in NH_3. The as-obtained NS-CNRs had a diamete...NS codoped carbon nanorods（NS-CNRs） were prepared using crab shell as template and polyphenylene sulfide（PPS） as both the C and S precursor, followed by carbonization in NH_3. The as-obtained NS-CNRs had a diameter of ~50 nm, length of several micrometers, and N and S contents of 12.5 at.% and 3.7 at.%,respectively, which can serve as anodes for both lithium-ion batteries（LIBs） and sodium ion batteries（SIBs）. When serving as an anode of LIB, the NS-CNRs delivered gravimetric capacities of 2154 mAh g^（-1）at current densities of 0.1 A g^（-1）and 625 mAh g^（-1）at current densities of 5.0 A g^（-1）for 1000 cycles.When serving as an anode of SIB, the NS-CNRs delivered gravimetric capacities of 303 mAh g^（-1）at current densities of 0.1 A g^（-1）and 230 mAh g^（-1）at current densities of 1.0 A g^（-1）for 3000 cycles. The excellent electrochemical performance of NS-CNRs could be ascribed to the one-dimensional nanometer structure and high level of heteroatom doping. We expect that the obtained NS-CNRs would benefit for the future development of the doped carbon materials for lithium ion batteries and other extended applications such as supercapacitor, catalyst and hydrogen storage.展开更多
Adsorption is an effective and low-cost method for removing antibiotics and dyes. However, it remains a challenge to prepare an adsorbent with excellent adsorption properties for both various antibiotics and dyes. Her...Adsorption is an effective and low-cost method for removing antibiotics and dyes. However, it remains a challenge to prepare an adsorbent with excellent adsorption properties for both various antibiotics and dyes. Herein, Fe/Cr-codoped ZnO with high adsorption capacity and fast adsorption rate are prepared by an environmentally friendly solvothermal method. Fe/Cr-codope ZnO with a diameter of 10–20 nm exhibits superior adsorption capacities for the antibiotics of tetracycline hydrochloride(TC-HCl)(826.45 mg g-1) and tetracycline(TC)(331.01 mg g-1), and anionic dyes of methyl orange(MO)(1023.88 mg g-1), methyl blue(MB)(726.26 mg g-1) and direct red(DR)(642.25 mg g-1). Meanwhile, it presents fast adsorption rate, it only took 30 min to reach more than 90% of the equilibrium adsorption amount for TC-HCl, TC, MO, MB and DR. The adsorption process closely fitted the Langmuir isotherm model and pseudo second-order rate equation. More importantly, simple method has been developed for separating the pollutant from the adsorbent, which not only regenerates the materials, but also completes the recovery of antibiotics and dyes, avoiding the secondary pollution. The broad-spectrum, rapid, environment-friendly and effective adsorption properties make Fe/Crcodoped ZnO a promising adsorbent for water treatments.展开更多
Nanopowders of Znl_x_y_zMnxNiyLizO [（x = 0.04, y = 0, z = 0）, （x = 0.04, y = 0.03, z = 0） and （x = 0.04, y = 0.03, z = 0.03）] have been synthesized by sol-gel precursor route using ethylene diamine tetraacetic a...Nanopowders of Znl_x_y_zMnxNiyLizO [（x = 0.04, y = 0, z = 0）, （x = 0.04, y = 0.03, z = 0） and （x = 0.04, y = 0.03, z = 0.03）] have been synthesized by sol-gel precursor route using ethylene diamine tetraacetic acid （EDTA） as a metal chelating agent. X-ray diffraction analysis confirms the formation of wurtzite hexagonal structure for all the three compositions. Mn2＋ doped ZnO exhibits room temperature ferromagnetism （RTFM）, and it is found that further Ni2＋ doping has decreased Ms because of limit of solid solubility of transition metal in ZnO. But codoping of monovalent Li1＋, further increases the ferromagnetism （FM） value, due to introduction of free carriers compared to the dual doped samples. Photoluminescence （PL） spectra of the system, exhibit near band edge （NBE） emission peak at --464 nm due to the electron transition from interstitials to the valence band. Recombination of conduction electron with hole trapped at oxygen vacancy, leads to prominent defect emission peaks at --482 nm and 532 nm. The evidence of the formation of metaI-EDTA complexes are found from the Fourier transform infrared spectra at 2800-3800 cm-1 with shifting, splitting of the peak and also drastic variations in the intensity.展开更多
The nonuniform Yb-Er Codoped Al2O3 films were prepared on SiO2/Si substrates using a medium frequency magnetron sputtering system. Two asymmetry targets in the system were introduced to realize the nonuniform dopant. ...The nonuniform Yb-Er Codoped Al2O3 films were prepared on SiO2/Si substrates using a medium frequency magnetron sputtering system. Two asymmetry targets in the system were introduced to realize the nonuniform dopant. Some curves of Photoluminescence （PL） peak intensity were obtained by adjusting the deposition parameters, such as, the pillar number of erbium and ytterbium in the mixed target and the distance between a sample table and targets. Typically, the curve of PL peak intensity against the offset distance was approximately linear. The ratio of the PL intensity at the two ends of the same sample was 12.6 and the slope was 71.83/mm when the pillar numbers of the erbium and ytterbium in the mixed target are 5 and 60, respectively, and the distance between targets and the sample table is 2.9 cm.展开更多
Nano-F-/Ce3+/TiO2 particles were prepared by hydrolysis of tetrabutyl titanate in a mixed CF3COOH-Ce(NO3)3-H2O solution. The photocatalytic decomposition of methylene blue in aqueous solution was used to evaluate thei...Nano-F-/Ce3+/TiO2 particles were prepared by hydrolysis of tetrabutyl titanate in a mixed CF3COOH-Ce(NO3)3-H2O solution. The photocatalytic decomposition of methylene blue in aqueous solution was used to evaluate their photocatalytic activities. The powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersion X-ray spectrum (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis. The results showed that F- and Ce3+ were doped into TiO2. The appropriate content of fluorine and cerium were 2.0% and 1.0% (atom fraction) respectively. The codoped nano-F-/Ce3+/TiO2 particles had higher BET specific surface area, smaller crystallite size and higher photocatalytic activity than those of undoped TiO2 particles.展开更多
The modeling of rare-earth-doped fiber amplifier is accomplished by utilizing the rate and propagation equations of distinct levels for a laser medium. A complex theoretical model for neodymium （Nd3＋）, erbium （Er...The modeling of rare-earth-doped fiber amplifier is accomplished by utilizing the rate and propagation equations of distinct levels for a laser medium. A complex theoretical model for neodymium （Nd3＋）, erbium （Er3＋）, thulium （Tm3＋） and ytterbium （Yb3＋） codoped telluride glass fiber covering 0.4--2.0 μm emission spectra is presented. The emission spectra of Nd3＋-Er3＋-Tm3＋-yb3＋ codoped telluride fiber are realized with the excitation of both 808 and 980 nm lasers pumped at 500 mW. Numerical methods are used to calculate the emission spectra covering 0.4--2.0 μm. With the Nd3＋, Tm3＋ and Yb3＋ ion concentrations fixed at 2 x 1020 ion/m3, the Er3＋ ion concentration optimized to 8 x 10^20 ion/m3 and the fiber length spanning from 0.5 to 2 m, a peak amplified spontaneous emission （ASE） power of 19.8 mW is attainable, and a minimum ASE power of 7.96 mW can also be achieved. The analytical techniques and results indicate that when a telluride codoped fiber with suitable ion concentrations of Nd3＋, Er3＋, Tm3＋ and Yb3＋ is excited by both 980 and 808 nm pump lasers, 0.4-2.0 μm emission spectra are attainable for vast optical applications.展开更多
An efficient and compact double-pass optical fiber amplifier is demonstrated using a newly developed hafnia bismuth erbium co-doped fiber（HBEDF） as a gain medium. The HBEDF is fabricated using a modified chemical va...An efficient and compact double-pass optical fiber amplifier is demonstrated using a newly developed hafnia bismuth erbium co-doped fiber（HBEDF） as a gain medium. The HBEDF is fabricated using a modified chemical vapor deposition in conjunction with solution doping. The fiber has an erbium ion concentration of 12500 ppm.At the optimum length of 0.5 m, the HBEDF amplifier（HBEDFA） achieves a flat gain of 26 d B with a gain variation of less than 1.5 d B within a wavelength region from 1530 to 1560 nm when the input signal and pump power are fixed at-30 d Bm and 140 m W, respectively. On the other hand, at the input signal power of-10 d Bm,the HBEDFA also achieves a flat gain of 14.2 d B with a gain variation of less than 2.5 d B within a wide wavelength region from 1525 to 1570 nm. Compared with the conventional zirconia erbium co-doped fiber based amplifier,the proposed HBEDFA obtains a more efficient gain and lower noise figure. For an input signal of-30 d Bm, the gain improvements of 6.2 d B and 4.8 d B are obtained at 1525 nm and 1540 nm, respectively.展开更多
Codoping approach is an appealing strategy to further improve the catalytic activity of Ce-based catalysts.In the present study,Mn and/or Cu doped ceria solid solutions MnxCuyCe1-x-yO2,CuxCe1-xO2,MnxCe1-xO2 and pure C...Codoping approach is an appealing strategy to further improve the catalytic activity of Ce-based catalysts.In the present study,Mn and/or Cu doped ceria solid solutions MnxCuyCe1-x-yO2,CuxCe1-xO2,MnxCe1-xO2 and pure CeO2 were prepared by CTAB-assisted hydrothermal method for CO oxidation.XRD,SEM,EDS,BET,Raman,H2-TPR,XPS and in situ DRIFTS techniques were carried out to study the physicochemical properties and to correlate them to the activity.The doped samples maintain the cubic fluorite structure of CeO2 with high crystallinity and small crystallite size,forming Ce-based solid solutions.The obtained catalysts have large mesoporous structure with average pore size of 10-14 nm.The doped transition metal enhances the oxygen vacancies and improves reducibility of the solids.The synergistic interaction of Mn and Cu codoping induces mo re oxygen vacancies,pro moting the increase of surface adsorbed oxygen and the transfer of bulk oxygen of catalyst,thereby enhancing the catalytic activity for CO oxidation.Besides,the decomposition rate of the carbonate species which is derived from in situ DRIFTS for each catalyst can provide a measure to evaluate its catalytic activity of CO oxidation.展开更多
The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattic...The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattice expansion for the codoped anatase TiO2 due to large atomic radius of the codoped atom.The calculated substitution energies indicate that incorporation of X（X =S,Se,Te） into N-doped bulk TiO2 can not promote synergistic effect on N after substituting for Ti,whcreas it is bctter after substituting for O.According to the total density of states （DOS） and corresponding partial DOS （PDOS）,it can be seen that substituting X（X =S,Se,Te） for O,N 2p orbital is strongly hybridized with impurity states （S 3p,Se 4p,Te 5p）.After substituting X（X=S,Se,Te） for Ti,conduction band is mainly dominated by Ti 3d orbit and S 3p （Se 4p or Te 5p）-N 2p-Ti 3d hybridized states are formed.Based on Bader analysis,it can be indicated that the electron transfer is from N to X（X=S,Se,Te） if substituting X（X=S,Se,Te） for O,but it is opposite if substitute X（X=S,Se,Te） for Ti.展开更多
Porous C‐I codoped carbon nitride materials were synthesized by in‐situ codoping with iodized ionic liquid followed by post‐thermal treatment in air.The effects of doping content of C‐I codoping with different amo...Porous C‐I codoped carbon nitride materials were synthesized by in‐situ codoping with iodized ionic liquid followed by post‐thermal treatment in air.The effects of doping content of C‐I codoping with different amounts of ionic liquid on the structural,optical and photocatalytic properties of the samples were investigated.Characterization results show that more compact interlayer sacking can be achieved by post‐thermal treatment.Combined with C‐I codoping by insertion of ionic liquids,much enlarged surface area but optimized sp2 conjugated heterocyclic structure can be found in the catalysts.Optical and energy band analysis results evidence that the light absorptions especially in visible light region are significantly improved.Although the band gap of porous C‐I codoped samples enlarge because of the generation of porous,the negatively shifted conduction band position thermodynamically supplies stronger motivation for water reduction.Photoelectricity tests reveal that the photo‐induced electron density was increased after C‐I codoping modification.Also,the recombination rate of electron‐hole pairs is remarkably inhibited.The catalysts with moderate C‐I codoing content perform sharply enhanced photocatalytic H2 evolution activity under visible light irradiation.A H2 evolution rate of 168.2μmol/h was achieved and it was more than 9.8 times higher than pristine carbon nitride.This study demonstrates a novel non‐metal doping strategy for synthesis and optimization of polymer semiconductor with gratifying photocatalytic H2 evolution performance from water hydrolysis.展开更多
基金Project supported by the National Natural Science Foundation of China(61805134,11974229,22303044)Fundamental Research Program of Shanxi Province(202203021221121)+3 种基金China Postdoctoral Science Foundation(2022M711898)Natural Science Fo undation of Shandong Province(ZR2023QB135)Postdoctoral Innovation Project of Shandong Province(SDCX-ZG-202201004)Graduate Innovation Project in Shanxi Province(2024KY450)。
文摘Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(+)-Eu^(3+)codoped Cs_(2)NaInCl_(6)nanocrystals were investigated.The pe rovskite nanocrystals exhibit a broad warm-white photo luminescence with correlated color temperature(CCT)of 3447 K and color rendering index(CRI)of 90.2,and the means of codoping would improve its optical performance.A fast energy transfer and a long-lived self-trapped excitons state are unveiled by the femtosecond transient absorption spectra.The fast energy transfer from the self-trapped excitons of host nanocrystals to the Eu^(3+)ions is helpful to achieve a broad photoluminescence,and the quantum yield of Cs_(2)NaInCl_(6):0.05Ag^(+)-Eu^(3+)anocrystals can be enha nced to 69.5%.There is a large exciton binding energy and strong electron-phonon interaction in the codoped perovskite nanocrystals.The efficient and excellent air-stable double perovskite nanocrystals would be considered as a single-component phosphor for warm-white lighting.
基金This work was supported by the National Natural Sci- ence Foundation of China （No.11034006, No.21273208, and No.21473168）, the Anhui Provincial Natural Sci- ence Foundation （No.1408085QB26）, the hmdamental Research Funds for the Central Universities, the China Postdoctoral Science Foundation （No.2012M511409）, and the Supercomputing Center of Chinese Academy of Sciences, Shanghai and USTC Supercomputer Cen- ters.
文摘Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.
基金financially supported by the National Natural Science Foundation of China(Nos.21875165,51772216 and 21703161)the Science and Technology Commission of Shanghai Municipality,China(No.14DZ2261100)the Fundamental Research Funds for the Central Universities。
文摘Pore size and distribution in carbon-based materials are regarded to be a key factor to affect the electrochemical capacitive performances of the resultant electrodes.In this study,nitrogen and oxygen codoped porous carbons(NOPCs) are fabricated based on a simple Schiff-base reaction between m-phenylenediamine and terephthalaldehyde.The NOPCs have tunable morphologies,high surface areas,abundant heteroatom doping.More importantly,the carbons show a dominant micropores of 0.5-0.8 nm,comparable to the ionic sizes of LiTFSI(Li^+0.069 nm;TFSI-0.79 nm) water-in-salt electrolyte with a high potential window of 2.2 V.Consequently,the fabricated symmetric supercapacitor gives a high energy output of 30.5 Wh/kg at 1 kW/kg,and high stability after successive 10,000 cycles with ^96.8% retention.This study provides promising potential to develop high-energy supercapacitors.
基金financial support of the National Natural Science Foundation of China (Grant No. 21263016, 21363015, 51662029, 21863006)the Youth Science Foundation of Jiangxi Province (Grant No. 20192BAB216001)the Key Laboratory of Jiangxi Province for Environment and Energy Catalysis (20181BCD40004)。
文摘Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxiety is the poor affinity toward polar polysulfides due to the intrinsic nonpolar surface of carbon.Herein, we report a direct pyrolysis of the mixture urea and boric acid to synthesize B/N–codoped hierarchically porous carbon nanosheets(B–N–CSs) as efficient sulfur host for lithium–sulfur battery. The graphene–like B–N–CSs provides high specific surface area and porous structure with abundant micropores(1.1 nm) and low–range mesopores(2.3 nm), thereby constraining the sulfur active materials within the pores. More importantly, the codoped B/N elements can further enhance the polysulfide confinement through strong Li–N and B–S interaction based on the Lewis acid–base theory. These structural superiorities significantly suppress the shuttle effect by both physical confinement and chemical interaction, and promote the redox kinetics of polysulfide conversion. When evaluated as the cathode host, the S/B–N–CSs composite displays the excellent performance with a high reversible capacity up to 772 m A h g–1 at 0.5 C and a low fading rate of ^0.09% per cycle averaged upon 500 cycles. In particular, remarkable stability with a high capacity retention of 87.1% can be realized when augmenting the sulfur loading in the cathode up to 4.6 mg cm^(-2).
基金supported by the National Key Research and Development Program of China (No. 2018YFC1802803)the National Natural Science Foundation of China (No. 21677041)the Science and Technology Project of Guangzhou City, China (No. 202103000018)。
文摘Simultaneous elimination of As(Ⅲ) and Pb(Ⅱ) from wastewater is still a great challenge.In this work,an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the remediate the co-pollution of As(Ⅲ) and Pb(Ⅱ).The positive enthalpy indicated that the adsorption in As-Pb co-pollution was an endothermic reaction.The mechanism of As(Ⅲ) removal could be illustrated by surface complexation,oxidation and precipitation.In addition to precipitation and complexation,the elimination mechanism of Pb(Ⅱ) also contained ion exchange and electrostatic interactions.Competitive and synergistic effects existed simultaneously in the co-contamination system.The suppression of As(Ⅲ) was ascribed to competitive complexation of the two metals on Fe/S-BC,while the synergy of Pb(Ⅱ) was attributed to the formation of the PbFe2(AsO_(4))2(OH)2.Batch experiments revealed that Fe/S-BC had outstanding ability to remove As(Ⅲ) and Pb(Ⅱ),regardless of pH dependency and interference by various coexisting ions.The maximum adsorption capacities of the Fe/S-BC for As(Ⅲ) and Pb(Ⅱ) were 91.2 mg/g and 631.7 mg/g,respectively.Fe/S-BC could be treated as a novel candidate for the elimination of As(Ⅲ)-Pb(Ⅱ) combined pollution.
基金Project supported by the National Natural Science Foundation of China (11574260)Hunan Provincial Graduate Research Innovation Project (CX2017B283)。
文摘Intense 1-5 μm infrared emission from near-to mid-infrared was obtained from Ho3+/Yb3+codoped TeO2-ZnF2 oxyfluorotellurite glasses which were prepared by melt-quenching method under the 980 nm LD excitation,and the emission intensity can be enhanced with the increase of ZnF2 content.Judd-Ofelt analysis was used to evaluate the radiative transition parameters of the excited levels according to the absorption spectra.The stimulated emission cross section of 5 I6→5 I8(1.2 μm),5 I7→5 I8(2.0μm),5 I6→5 I7(2.85 μm) and 5 I5→5 I6(4.0 μm) transitions were calculated to reach 0.639 × 10-20,0.760 ×10-20,0.985×10 20 and 0.484 × 10-20 cm2,respectively.The energy transfer coefficients(CDA) are enhanced with the increase of ZnF2 content and phonon contribution ratios of phonon assisted energy transfer process between Ho3+ and Yb3+were figured out.Our results demonstrate that these TeO2-ZnF2 glasses,which possess good thermal stability and transparency,low phonon energy(about 600 cm-1),excellent near-and mid-infrared emission in the range of 1-5 μm wavelength,would be promising material for infrared optical fibers and infrared lasers.
基金Project supported by China Postdoctoral Science Foundation funded project (20080430216)National Natural Science Foundation of China (60508014)+1 种基金Program for New Century Excellent Talents in University (NCET-07-0786)Zhejiang Provincial Natural Science Foundation of China (Z4100030)
文摘Er3+/Yb3+-codoped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared and spectroscopic properties of rare earth ions were investigated. Fluoride nanocrystals Ba2GdF7 were successfully precipitated in glass matrix, which was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) results. In comparison with the as-made precursor, significant enhancement of upconversion luminescence was observed in the Er3+/Yb3+ codoped oxyfluoride glass ceramics, which may be due to the variation of coordination environment around Er3+ and Yb3+ ions after crystallization. The transition mechanisms of the green and red upconversion luminescence were ascribed to a two-photon process, and that of the blue upconversion luminescence was a three-photon process.
基金Project supported by the Shanghai ＂Post-Qi-Ming-Xing plan＂ for Young Scientists, China （Grant No 04QMX1448） and the National Natural Science Foundation of China （Grant No 60207006）.The author would like to thank Wen L,Shen Y H and Zhao Y for their help in machining and measuring.
文摘Novel oxyfluoride glasses are developed with the composition of 30SiO2-15Al2O3-28PbF2-22CdF2-0.1TmF3 - xYbF3 - （4.9 - x） AlF3（x=0, 0.5, 1.0, 1.5, 2.0） in tool fraction, Furthermore, the upconversion luminescence characteristics under a 970nm excitation are investigated. Intense blue, red and near infrared luminescences peaked at 453nm, 476nm, 647nm and 789nm, which correspond to the transitions of Tm^3＋： ^1D2 →^3F4, ^1G4 →^3H6, ^1G4 →^3F4, and ^3H4 →^3H6, respectively, are observed. Due to the sensitization of Yb^3＋ ions, all the upconversion luminescence intensities are enhanced considerably with Yb^3＋ concentration increasing. The upconversion mechanisms are discussed based on the energy matching rule and quadratic dependence on excitation power. The results indicate that the dominant mechanism is the excited state absorption for those upconversion emissions.
基金supported by the National Basic Research Program of China under Grant No.2006CB604906the National Natural Science Foundation of China under Grant No.51072181the Doctoral Fund of Ministry of Education of China under Grant No.20060335087
文摘Effects of growth temperature on the structural and electrical properties of Li-N-H codoped ZnO thin films grown by DC reactive magnetron sputtering were investigated. Scanning electron microscopy and X-ray diffraction results showed that increasing growth temperature could improve the crystalline quality. But Hall measurement results showed that growth temperature had a nonlinear influence on the electrical property. The variation of electrical properties with the growth temperature was found to be related to the activated concentration of N in ZnO and the evaporation of Li during the growth process, derived from the Hall measurement and the second ion mass spectroscopy measurement.
基金Project supported by the Higher School Science Research Outstanding Youth Fund Project of Ningxia,China(Grant No.NGY2015049)
文摘The electronic structures and magnetic properties of the Cu and N codoped 3C-Si C system have been investigated by the first-principles calculation.The results show that the Cu doped Si C system prefers the anti-ferromagnetic（AFM） state.Compared to the Cu doped system,the ionicities of C–Cu and C–Si in Cu and N codoped Si C are respectively enhanced and weakened.Especially,the Cu and N codoped Si C systems favor the ferromagnetic（FM） coupling.The FM interactions can be explained by virtual hopping.However,higher N concentration will weaken the ferromagnetism.In order to keep the FM interaction,the N concentration should be restricted within 9.3% according to our analysis.
基金the National Key Basic Research Program of China (2015CB351903)the National Natural Science Foundation of China (51402282, 51373160,21474095, 21476104, 21373197)+1 种基金the Fundamental Research Funds for the Central Universities (WK3430000003)the 100 Talents Program of the Chinese Academy of Sciences
文摘NS codoped carbon nanorods（NS-CNRs） were prepared using crab shell as template and polyphenylene sulfide（PPS） as both the C and S precursor, followed by carbonization in NH_3. The as-obtained NS-CNRs had a diameter of ~50 nm, length of several micrometers, and N and S contents of 12.5 at.% and 3.7 at.%,respectively, which can serve as anodes for both lithium-ion batteries（LIBs） and sodium ion batteries（SIBs）. When serving as an anode of LIB, the NS-CNRs delivered gravimetric capacities of 2154 mAh g^（-1）at current densities of 0.1 A g^（-1）and 625 mAh g^（-1）at current densities of 5.0 A g^（-1）for 1000 cycles.When serving as an anode of SIB, the NS-CNRs delivered gravimetric capacities of 303 mAh g^（-1）at current densities of 0.1 A g^（-1）and 230 mAh g^（-1）at current densities of 1.0 A g^（-1）for 3000 cycles. The excellent electrochemical performance of NS-CNRs could be ascribed to the one-dimensional nanometer structure and high level of heteroatom doping. We expect that the obtained NS-CNRs would benefit for the future development of the doped carbon materials for lithium ion batteries and other extended applications such as supercapacitor, catalyst and hydrogen storage.
基金supported by the National Natural Science Foundation of China (Nos. 51672144, 51572137, 51702181)the Natural Science Foundation of Shandong Province (Nos. ZR2017BB013, ZR2019BEM042)+2 种基金the Higher Educational Science and Technology Program of Shandong Province (Nos. J17KA014, J18KA001, J18KA033)the Taishan Scholars Program of Shandong Province (No. ts201511034)the Overseas Taishan Scholars Program。
文摘Adsorption is an effective and low-cost method for removing antibiotics and dyes. However, it remains a challenge to prepare an adsorbent with excellent adsorption properties for both various antibiotics and dyes. Herein, Fe/Cr-codoped ZnO with high adsorption capacity and fast adsorption rate are prepared by an environmentally friendly solvothermal method. Fe/Cr-codope ZnO with a diameter of 10–20 nm exhibits superior adsorption capacities for the antibiotics of tetracycline hydrochloride(TC-HCl)(826.45 mg g-1) and tetracycline(TC)(331.01 mg g-1), and anionic dyes of methyl orange(MO)(1023.88 mg g-1), methyl blue(MB)(726.26 mg g-1) and direct red(DR)(642.25 mg g-1). Meanwhile, it presents fast adsorption rate, it only took 30 min to reach more than 90% of the equilibrium adsorption amount for TC-HCl, TC, MO, MB and DR. The adsorption process closely fitted the Langmuir isotherm model and pseudo second-order rate equation. More importantly, simple method has been developed for separating the pollutant from the adsorbent, which not only regenerates the materials, but also completes the recovery of antibiotics and dyes, avoiding the secondary pollution. The broad-spectrum, rapid, environment-friendly and effective adsorption properties make Fe/Crcodoped ZnO a promising adsorbent for water treatments.
文摘Nanopowders of Znl_x_y_zMnxNiyLizO [（x = 0.04, y = 0, z = 0）, （x = 0.04, y = 0.03, z = 0） and （x = 0.04, y = 0.03, z = 0.03）] have been synthesized by sol-gel precursor route using ethylene diamine tetraacetic acid （EDTA） as a metal chelating agent. X-ray diffraction analysis confirms the formation of wurtzite hexagonal structure for all the three compositions. Mn2＋ doped ZnO exhibits room temperature ferromagnetism （RTFM）, and it is found that further Ni2＋ doping has decreased Ms because of limit of solid solubility of transition metal in ZnO. But codoping of monovalent Li1＋, further increases the ferromagnetism （FM） value, due to introduction of free carriers compared to the dual doped samples. Photoluminescence （PL） spectra of the system, exhibit near band edge （NBE） emission peak at --464 nm due to the electron transition from interstitials to the valence band. Recombination of conduction electron with hole trapped at oxygen vacancy, leads to prominent defect emission peaks at --482 nm and 532 nm. The evidence of the formation of metaI-EDTA complexes are found from the Fourier transform infrared spectra at 2800-3800 cm-1 with shifting, splitting of the peak and also drastic variations in the intensity.
基金Project supported by the National Natural Science Foundation of China (60477023)the Natural Science Foundation of Science and Tech-nology Commission of Liaoning Province (20062137)
文摘The nonuniform Yb-Er Codoped Al2O3 films were prepared on SiO2/Si substrates using a medium frequency magnetron sputtering system. Two asymmetry targets in the system were introduced to realize the nonuniform dopant. Some curves of Photoluminescence （PL） peak intensity were obtained by adjusting the deposition parameters, such as, the pillar number of erbium and ytterbium in the mixed target and the distance between a sample table and targets. Typically, the curve of PL peak intensity against the offset distance was approximately linear. The ratio of the PL intensity at the two ends of the same sample was 12.6 and the slope was 71.83/mm when the pillar numbers of the erbium and ytterbium in the mixed target are 5 and 60, respectively, and the distance between targets and the sample table is 2.9 cm.
基金the Natural Science Foundation of Hebei Province (203364)the Natural Science Foundation of Hebei University of Science and Technology (XL2006038)
文摘Nano-F-/Ce3+/TiO2 particles were prepared by hydrolysis of tetrabutyl titanate in a mixed CF3COOH-Ce(NO3)3-H2O solution. The photocatalytic decomposition of methylene blue in aqueous solution was used to evaluate their photocatalytic activities. The powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersion X-ray spectrum (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis. The results showed that F- and Ce3+ were doped into TiO2. The appropriate content of fluorine and cerium were 2.0% and 1.0% (atom fraction) respectively. The codoped nano-F-/Ce3+/TiO2 particles had higher BET specific surface area, smaller crystallite size and higher photocatalytic activity than those of undoped TiO2 particles.
基金the National Natural Science Foundation of China(Nos.60377023 and 60672017)the Program for New Century Excellent Talents in Universities(NCET)Shanghai Optical Science and Technology Project(No.05DZ22009)
文摘The modeling of rare-earth-doped fiber amplifier is accomplished by utilizing the rate and propagation equations of distinct levels for a laser medium. A complex theoretical model for neodymium （Nd3＋）, erbium （Er3＋）, thulium （Tm3＋） and ytterbium （Yb3＋） codoped telluride glass fiber covering 0.4--2.0 μm emission spectra is presented. The emission spectra of Nd3＋-Er3＋-Tm3＋-yb3＋ codoped telluride fiber are realized with the excitation of both 808 and 980 nm lasers pumped at 500 mW. Numerical methods are used to calculate the emission spectra covering 0.4--2.0 μm. With the Nd3＋, Tm3＋ and Yb3＋ ion concentrations fixed at 2 x 1020 ion/m3, the Er3＋ ion concentration optimized to 8 x 10^20 ion/m3 and the fiber length spanning from 0.5 to 2 m, a peak amplified spontaneous emission （ASE） power of 19.8 mW is attainable, and a minimum ASE power of 7.96 mW can also be achieved. The analytical techniques and results indicate that when a telluride codoped fiber with suitable ion concentrations of Nd3＋, Er3＋, Tm3＋ and Yb3＋ is excited by both 980 and 808 nm pump lasers, 0.4-2.0 μm emission spectra are attainable for vast optical applications.
文摘An efficient and compact double-pass optical fiber amplifier is demonstrated using a newly developed hafnia bismuth erbium co-doped fiber（HBEDF） as a gain medium. The HBEDF is fabricated using a modified chemical vapor deposition in conjunction with solution doping. The fiber has an erbium ion concentration of 12500 ppm.At the optimum length of 0.5 m, the HBEDF amplifier（HBEDFA） achieves a flat gain of 26 d B with a gain variation of less than 1.5 d B within a wavelength region from 1530 to 1560 nm when the input signal and pump power are fixed at-30 d Bm and 140 m W, respectively. On the other hand, at the input signal power of-10 d Bm,the HBEDFA also achieves a flat gain of 14.2 d B with a gain variation of less than 2.5 d B within a wide wavelength region from 1525 to 1570 nm. Compared with the conventional zirconia erbium co-doped fiber based amplifier,the proposed HBEDFA obtains a more efficient gain and lower noise figure. For an input signal of-30 d Bm, the gain improvements of 6.2 d B and 4.8 d B are obtained at 1525 nm and 1540 nm, respectively.
基金Project supported by the National Natural Science Foundation of China(21777055)Shandong Provincial Natural Science Foundation(ZR2017BB004)+1 种基金Shandong Province Key Research and Development Plan(2017GGX202004)Shandong Province Major Science and Technology Innovation Project(2017CXGC1004)
文摘Codoping approach is an appealing strategy to further improve the catalytic activity of Ce-based catalysts.In the present study,Mn and/or Cu doped ceria solid solutions MnxCuyCe1-x-yO2,CuxCe1-xO2,MnxCe1-xO2 and pure CeO2 were prepared by CTAB-assisted hydrothermal method for CO oxidation.XRD,SEM,EDS,BET,Raman,H2-TPR,XPS and in situ DRIFTS techniques were carried out to study the physicochemical properties and to correlate them to the activity.The doped samples maintain the cubic fluorite structure of CeO2 with high crystallinity and small crystallite size,forming Ce-based solid solutions.The obtained catalysts have large mesoporous structure with average pore size of 10-14 nm.The doped transition metal enhances the oxygen vacancies and improves reducibility of the solids.The synergistic interaction of Mn and Cu codoping induces mo re oxygen vacancies,pro moting the increase of surface adsorbed oxygen and the transfer of bulk oxygen of catalyst,thereby enhancing the catalytic activity for CO oxidation.Besides,the decomposition rate of the carbonate species which is derived from in situ DRIFTS for each catalyst can provide a measure to evaluate its catalytic activity of CO oxidation.
基金Natural Science Foundation of Shanxi Province(No.2009011014)
文摘The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattice expansion for the codoped anatase TiO2 due to large atomic radius of the codoped atom.The calculated substitution energies indicate that incorporation of X（X =S,Se,Te） into N-doped bulk TiO2 can not promote synergistic effect on N after substituting for Ti,whcreas it is bctter after substituting for O.According to the total density of states （DOS） and corresponding partial DOS （PDOS）,it can be seen that substituting X（X =S,Se,Te） for O,N 2p orbital is strongly hybridized with impurity states （S 3p,Se 4p,Te 5p）.After substituting X（X=S,Se,Te） for Ti,conduction band is mainly dominated by Ti 3d orbit and S 3p （Se 4p or Te 5p）-N 2p-Ti 3d hybridized states are formed.Based on Bader analysis,it can be indicated that the electron transfer is from N to X（X=S,Se,Te） if substituting X（X=S,Se,Te） for O,but it is opposite if substitute X（X=S,Se,Te） for Ti.
基金the National Natural Science Foundation of China(21503096,21407067)the Natural Science Foundation of Jiangsu Province(BK20140506)~~
文摘Porous C‐I codoped carbon nitride materials were synthesized by in‐situ codoping with iodized ionic liquid followed by post‐thermal treatment in air.The effects of doping content of C‐I codoping with different amounts of ionic liquid on the structural,optical and photocatalytic properties of the samples were investigated.Characterization results show that more compact interlayer sacking can be achieved by post‐thermal treatment.Combined with C‐I codoping by insertion of ionic liquids,much enlarged surface area but optimized sp2 conjugated heterocyclic structure can be found in the catalysts.Optical and energy band analysis results evidence that the light absorptions especially in visible light region are significantly improved.Although the band gap of porous C‐I codoped samples enlarge because of the generation of porous,the negatively shifted conduction band position thermodynamically supplies stronger motivation for water reduction.Photoelectricity tests reveal that the photo‐induced electron density was increased after C‐I codoping modification.Also,the recombination rate of electron‐hole pairs is remarkably inhibited.The catalysts with moderate C‐I codoing content perform sharply enhanced photocatalytic H2 evolution activity under visible light irradiation.A H2 evolution rate of 168.2μmol/h was achieved and it was more than 9.8 times higher than pristine carbon nitride.This study demonstrates a novel non‐metal doping strategy for synthesis and optimization of polymer semiconductor with gratifying photocatalytic H2 evolution performance from water hydrolysis.
