A zinc phthalocyanine containing (17-crown-5) ether subunits has been synthesized.UV-visible absorption and fluorescence emission spectra and associated photophysical parameters have been determined. In addition to th...A zinc phthalocyanine containing (17-crown-5) ether subunits has been synthesized.UV-visible absorption and fluorescence emission spectra and associated photophysical parameters have been determined. In addition to the fluorescence at 710 nm from S1. a strong upper excited state emission around 424 nm has been detected. X-ray structural analysis showed that the crown ether unit is conformationally deformed and oblate like that accounted for the unusual spectroscopic展开更多
The optical and thermal properties of a new class of fluoroindate glass with different erbium contents were investigated via Raman,transmission,and fluorescence spectroscopies,fluorescence decay curve analysis,and dif...The optical and thermal properties of a new class of fluoroindate glass with different erbium contents were investigated via Raman,transmission,and fluorescence spectroscopies,fluorescence decay curve analysis,and differential scanning calorimetry.The strength parameters of the samples were calculated using the Judd-Ofelt theory.The mid-infrared luminescence properties of erbium-doped fluoroindate glasses were studied,and a strong emission at 2.7μm was obtained.Compared with the traditional ZBLAN glass,this glass has excellent emission properties,especially a longer fluorescence lifetime(7.09 ms)and larger emission cross-section(6.95×10^(-21) cm^(2))at 2.7μm.The results indicate that fluoroindate glass is an attractive host for mid-infrared lasers and as a gain medium for optical amplifier applications.展开更多
A series of five different concentration erbium-doped tellurite glasses with various hydroxl groups were prepared. Infrared spectra of glasses were measured. In order to estimate the exact content of OH? groups in sam...A series of five different concentration erbium-doped tellurite glasses with various hydroxl groups were prepared. Infrared spectra of glasses were measured. In order to estimate the exact content of OH? groups in samples, various absorption coefficients of the OH? vibration band were analyzed under the different oxygen bubbling times. The absorption spectra of the glasses were measured, and the Judd-Ofelt intensity parameters ?i of samples with the different erbium ions concentration and OH? contents were calculated on the basis of the Judd-Ofelt theory. The peak stimulated emission cross-section of 4I13/2→4I15/2 transition of the samples was finally calculated by using the McCumber theory. The fluorescence spectra of Er3+:4I13/2→4I15/2 transition and the lifetime of Er3+:4I13/2 level of the samples were measured. The effects of OH? groups on the spectroscopic properties of Er3+ doped samples with the different concentrations were discussed. The results showed that the OH? groups had great influences on the Er3+ lifetime and the fluorescence peak intensity. The OH? group is a main influence factor of fluorescence quenching when the doping concentration of Er2O3 is smaller than 1.0 mol%, but higher after this concentration, the energy transfer of Er3+ ions turns into the main function of the fluorescence quenching. And basically, there is no influence on the other spectroscopic properties (FWHM, absorption spectra, peak stimulated emission cross section, etc.).展开更多
Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herei...Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herein, we focus on the interaction between nickel(Ⅱ) and the porphyrin skeleton. Five different density functionals were selected for determining a reliable approach to simulate porphyrin-nickel(Ⅱ) complexes. At D4h symmetry, the 10b1g, 15a1g, 4e1g and 9b2g were dominated by the 3d character of nickel. Compared with pure density functional, the hybrid functional gave larger highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) gap, and the higher HOMO-LUMO gap also corresponded to a higher excitation energy. The characteristic Soret and Q bands modeled by timedependent density functional theory(TDDFT) calculations matched well with experimental results, and the absorption was discussed in detail with natural transition orbitals(NTO) analysis. Furthermore, the binding character of nickel(Ⅱ) with various substituted porphyrins were calculated at perdew-burke-ernzerhof(PBE) level, showed that the geometry and complexation behavior of porphyrin-nickel(Ⅱ) complexes could be significantly tuned by different substituents. The symmetry of the complex was reduced and the skeleton ring get distortion when introducing different substituents. Compared with ETIO porphyrin, the introduction of phenyl on the β position can expand the conjugated system and promote the covalent character of Ni-N bond.展开更多
Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radia...Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radiative transition probabilities AJ,J',oscillator strengths PJ,J',radiative lifetime τ,fluorescence branch ratios βJ and the value of integrated emission cross section have also been calculated.Five main absorption bands,3H4 to 3P1+3P2,3P0,1D2,3F3 + 3F4 and 3F2,were observed in the absorption spectra.The 1G4 absorption band was not observed.A very strong emission band at 601 nm(1D2→3H4) was observed in the emission spectra.The experimental lifetime for this level was compared with that obtained theoretically by using J-O approach.展开更多
The reaction of 5-hydroxyl-7-methoxyflavone(tectochrysin) with bromine obtained 3,6,8-tribromo-5-hydroxy-2,7-dimethoxy-2,3-dihydrochromen-4-one(1), which was characterized by FT-IR, 1 H-NMR, ^(13)C-NMR, elemental anal...The reaction of 5-hydroxyl-7-methoxyflavone(tectochrysin) with bromine obtained 3,6,8-tribromo-5-hydroxy-2,7-dimethoxy-2,3-dihydrochromen-4-one(1), which was characterized by FT-IR, 1 H-NMR, ^(13)C-NMR, elemental analysis and X-ray single-crystal diffraction. Complex 1 belongs to the monoclinic system, space group pbca with a = 9.4673(8), b = 17.9938(15), c = 21.2004(17) ?, V = 3611.5(5) ?~3, Z = 8, μ = 0.6726 mm^(-1), Dc = 1.795 g/cm3, F(000) = 2080, the final R = 0.0358 and wR = 0.0644 with I > 2σ(I). The results show that the addition reaction occurs at the carbon-carbon double bond(C2 and C3) of tectochrysin and 1 belongs to dihydroflavone. The reaction mechanism was discussed and the structure revealed that the crystal structure of 1 is stabilized by intramolecular hydrogen bonds and C–Br···π interactions. The antitumor ability of 1 was evaluated against human leukemia cells(K562), human breast cancer cells(MCF-7) and human lung cancer cells(A549). 1 exhibited potent antitumor activities against human leukemia cells(K562) with the IC50 values of 18.9 μmol/L.展开更多
The Yb:Lu_(2)O_(3)precursor made up of spherical particles was synthesized through the co-precipitation method in the water/ethanol solvent.The 5 at% Yb:Lu_(2)O_(3)powder is in the cubic phase after calcination at 110...The Yb:Lu_(2)O_(3)precursor made up of spherical particles was synthesized through the co-precipitation method in the water/ethanol solvent.The 5 at% Yb:Lu_(2)O_(3)powder is in the cubic phase after calcination at 1100℃ for 4 h.The powder also consists of spherical nanoparticles with the average particle and grain sizes of 96 and 49 nm,respectively.The average grain size of the pre-sintered ceramic sample is 526 nm and that of the sample by hot isostatic pressing grows to 612 nm.The 1.0 mm-thick sample has an in-line transmittance of 81.6%(theoretical value of 82.2%)at 1100 nm.The largest absorption cross-section at 976 nm is 0.96×1^(0-20)cm^(2) with the emission cross-section at 1033 nm of 0.92×10^(-20)cm^(2) and the gain cross sections are calculated with the smallest population inversion parameter β of 0.059.The highest slope efficiency of 68.7% with the optical efficiency of 65.1% is obtained at 1033.3 nm in quasi-continuous wave(QCW)pumping.In the case of continuous wave(CW)pumping,the highest slope efficiency is 61.0% with the optical efficiency of 54.1%.The obtained laser performance indicates that Yb:Lu_(2)O_(3)ceramics have excellent resistance to thermal load stresses,which shows great potential in high-power solid-state laser applications.展开更多
In this work we repo rt on structural and spect roscopic properties of Yb^3+doped and Pr^3+/Yb^3+co-doped TeO2-Bi2 O3-ZnO-Li2 O-Nb2 O5(TBZLN)tellurite glasses.Bending and stretching modes of TeO2 and Te-OH bond(strong...In this work we repo rt on structural and spect roscopic properties of Yb^3+doped and Pr^3+/Yb^3+co-doped TeO2-Bi2 O3-ZnO-Li2 O-Nb2 O5(TBZLN)tellurite glasses.Bending and stretching modes of TeO2 and Te-OH bond(strong and weak)were analysed from the deconvolution of observed Raman and FT-IR spectra.Based on the absorption measurements,the energy bands of Yb^3+and Pr^3+ions are assigned.The spectroscopic properties for the radiative transitions of Yb^3+and Pr^3+ions were reported using McCumber and Judd-Ofelt theories.Visible emission bands originating from 3 P1 and 3 P0 to lower lying levels of Pr^3+were registered under 447 nm excitation.The emission band around 1334 nm assigned to the Pr3:1 G4→3 H5 was observed when excited at 980 nm.The stimulated emission cross-section(σemi(λ))and effective linewidth(Δλeff)for the 3 P1→3 H6,3 P1→3 H5,3 P0→3 H6,3 P0→3 F2,3 P1→3 F3,3 P1→3 F4,3 P0→3 F4 and 1 G4→3 H5 transitions of Pr^3+are reported.Upconversion luminescence in Pr^3+/Yb^3+codoped glass upon 980 nm excitation was measured.Possible resonant transfer processes between Yb^3+and Pr^3+ions are presented and discussed.The chromaticity co-ordinates were also evaluated from the visible emission spectra showing that Pr^3+/Yb^3+co-doped glass may be suitable for the development of yellow-orange(λexc=447 nm)and near white light(λexc=980 nm)emitting devices in photonics.展开更多
A pair of nickel(Ⅱ)complexes monomer and dimer,namely[NiCl2(L)](1)and[Ni2Cl2(L)2(μ-Cl)2](2)(L=2-morpholine-4-yl-4,6-di-pyrazol-1-yl-1,3,5-triazine),were synthesized by using L to react with NiCl2·2 H2 O at 35 a...A pair of nickel(Ⅱ)complexes monomer and dimer,namely[NiCl2(L)](1)and[Ni2Cl2(L)2(μ-Cl)2](2)(L=2-morpholine-4-yl-4,6-di-pyrazol-1-yl-1,3,5-triazine),were synthesized by using L to react with NiCl2·2 H2 O at 35 and 65℃,respectively.X-ray crystal structures of complexes 1 and 2 were determined.Complex 1 is mononuclear and its nickel(Ⅱ)center resides in a distorted square-pyramidal environment with a NiN3Cl2 donor set,but complex 2 is binuclear and its nickel(Ⅱ)center shows a distorted octahedral geometry with a NiN3Cl3 donor set.In complex 2,two adjacent nickel(Ⅱ)centers are connected by two bridging chloride anions.Complexes 1 and 2 form different three-dimensional supramolecular structures through non-covalent interactions such asπ-πstacking interactions,anion-πinteractions and weak hydrogen bonds.Both complexes were further characterized by thermal gravimetric analyses and spectroscopic methods.展开更多
Herein,melt-quenching and Er^(3+) doping were used to synthesize fluoride glass specimens with low phonon energies(582 cm^(-1)).These glass specimens exhibit intense 3.1 μm mid-infrared band emission when they are ex...Herein,melt-quenching and Er^(3+) doping were used to synthesize fluoride glass specimens with low phonon energies(582 cm^(-1)).These glass specimens exhibit intense 3.1 μm mid-infrared band emission when they are excited by a 980 nm laser diode,achieving a full width at half maximum(FWHM) of about166 nm.This 3.1 μm emission intensity is enhanced by the introduction of ZnF_(2) to the AlF_(3)-based fluoride glass.Up-conversion emission,strong near-infrared emission,and fluorescence lifetime are enhanced to different degrees by increasing the ZnF_(2) content.Moreover,the spectroscopic characteristics of the glass specimens and the highly efficient Er^(3+):~4S_(3/2)→~4F_(9/2) transition's energy transfer mechanism were investigated.The absorption spectra and emission spectra of these aluminum fluoride glass specimens were used to calculate their gain coefficients and maximum cross sections at 1.5 and 3.1 μm.Overall,the spectral properties of these prepared aluminum fluoride glass specimens demonstrate their high potential for use as infrared laser host materials.展开更多
A Yb^(3+):KBaY(MoO_(4))_(3)(Yb^(3+):KBYM)crystal with dimensions of 51 mm×27 mm × 10 mm was successfully grown by the TSSG method.The characteristics of the crystal structure and probability of good optical ...A Yb^(3+):KBaY(MoO_(4))_(3)(Yb^(3+):KBYM)crystal with dimensions of 51 mm×27 mm × 10 mm was successfully grown by the TSSG method.The characteristics of the crystal structure and probability of good optical properties were analyzed.The absorption and emission spectra of Yb^(3+):KBYM crystal exhibit broadened bands,with the maximum absorption cross-sections of 1.17 × 10^(-20),1.44×10^(-20) and 1.37 × 10^(-20) cm^(2) at976 nm for X-,Y-and Z-polarizations,respectively.The corresponding absorption FWHMs are as wide as 77,46 and 55 nm.The well-known re-absorption effect of Yb^(3+) in the crystal is discussed.Two methods,the Fiichtbauer-Ladenburg method(FL)and reciprocity method(RM)were adopted to compute the emission cross-sections and results show a certain discrepancy but the errors are allowable.The laser potentiality of the Yb^(3+):KBYM crystal was also evaluated by calculations of minimum inversion fractionβmin,saturation pump intensity Isat,the minimum pump intensity Imin and gain cross-sections spectra.Laser experiment was carried out and Watt-level continuous wave laser has been realized.Results indicate that the Yb^(3+):KBYM crystal with a disordered structure may be a potential laser media that can be used to generate tunable and ultrashort pulse laser emissions with high quality beam.展开更多
文摘A zinc phthalocyanine containing (17-crown-5) ether subunits has been synthesized.UV-visible absorption and fluorescence emission spectra and associated photophysical parameters have been determined. In addition to the fluorescence at 710 nm from S1. a strong upper excited state emission around 424 nm has been detected. X-ray structural analysis showed that the crown ether unit is conformationally deformed and oblate like that accounted for the unusual spectroscopic
基金Project supported by the National Natural Science Foundation of China(61308086)CAS Light of West China Program(2017447)。
文摘The optical and thermal properties of a new class of fluoroindate glass with different erbium contents were investigated via Raman,transmission,and fluorescence spectroscopies,fluorescence decay curve analysis,and differential scanning calorimetry.The strength parameters of the samples were calculated using the Judd-Ofelt theory.The mid-infrared luminescence properties of erbium-doped fluoroindate glasses were studied,and a strong emission at 2.7μm was obtained.Compared with the traditional ZBLAN glass,this glass has excellent emission properties,especially a longer fluorescence lifetime(7.09 ms)and larger emission cross-section(6.95×10^(-21) cm^(2))at 2.7μm.The results indicate that fluoroindate glass is an attractive host for mid-infrared lasers and as a gain medium for optical amplifier applications.
基金This work was supported by the National Natural Science Foundation of China(Grant No.60207006)the Shanghai QiMing Xing Program(Grant No.04QMX1448).
文摘A series of five different concentration erbium-doped tellurite glasses with various hydroxl groups were prepared. Infrared spectra of glasses were measured. In order to estimate the exact content of OH? groups in samples, various absorption coefficients of the OH? vibration band were analyzed under the different oxygen bubbling times. The absorption spectra of the glasses were measured, and the Judd-Ofelt intensity parameters ?i of samples with the different erbium ions concentration and OH? contents were calculated on the basis of the Judd-Ofelt theory. The peak stimulated emission cross-section of 4I13/2→4I15/2 transition of the samples was finally calculated by using the McCumber theory. The fluorescence spectra of Er3+:4I13/2→4I15/2 transition and the lifetime of Er3+:4I13/2 level of the samples were measured. The effects of OH? groups on the spectroscopic properties of Er3+ doped samples with the different concentrations were discussed. The results showed that the OH? groups had great influences on the Er3+ lifetime and the fluorescence peak intensity. The OH? group is a main influence factor of fluorescence quenching when the doping concentration of Er2O3 is smaller than 1.0 mol%, but higher after this concentration, the energy transfer of Er3+ ions turns into the main function of the fluorescence quenching. And basically, there is no influence on the other spectroscopic properties (FWHM, absorption spectra, peak stimulated emission cross section, etc.).
基金supported by National Key R & D program of China (No.2021YFA1501204)Contract Projects of China Petroleum & Chemical Corporation (SINOPEC Corp.) (grant number 123017grant number 121043-2)。
文摘Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herein, we focus on the interaction between nickel(Ⅱ) and the porphyrin skeleton. Five different density functionals were selected for determining a reliable approach to simulate porphyrin-nickel(Ⅱ) complexes. At D4h symmetry, the 10b1g, 15a1g, 4e1g and 9b2g were dominated by the 3d character of nickel. Compared with pure density functional, the hybrid functional gave larger highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) gap, and the higher HOMO-LUMO gap also corresponded to a higher excitation energy. The characteristic Soret and Q bands modeled by timedependent density functional theory(TDDFT) calculations matched well with experimental results, and the absorption was discussed in detail with natural transition orbitals(NTO) analysis. Furthermore, the binding character of nickel(Ⅱ) with various substituted porphyrins were calculated at perdew-burke-ernzerhof(PBE) level, showed that the geometry and complexation behavior of porphyrin-nickel(Ⅱ) complexes could be significantly tuned by different substituents. The symmetry of the complex was reduced and the skeleton ring get distortion when introducing different substituents. Compared with ETIO porphyrin, the introduction of phenyl on the β position can expand the conjugated system and promote the covalent character of Ni-N bond.
基金supported by the National Natural Science Foundation of China (50590402 and 50802100)
文摘Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radiative transition probabilities AJ,J',oscillator strengths PJ,J',radiative lifetime τ,fluorescence branch ratios βJ and the value of integrated emission cross section have also been calculated.Five main absorption bands,3H4 to 3P1+3P2,3P0,1D2,3F3 + 3F4 and 3F2,were observed in the absorption spectra.The 1G4 absorption band was not observed.A very strong emission band at 601 nm(1D2→3H4) was observed in the emission spectra.The experimental lifetime for this level was compared with that obtained theoretically by using J-O approach.
基金supported by Youth Backbone Teachers Project Funded by Xianyang Normal University(No.XSYGG201606)Scientific Research Program Funded by Shaanxi Provincial Education Department(No.16JK1822)+3 种基金Natural Science Basic Research Plan Funded by Shaanxi Province of China(No.2016JM5024)Science and Technology Projects of Xianyang City(No.2017k02-19)University Students Research and Innovation Training Program of Xianyang Normal University(No.2017060&201710722003)University Students Research and Innovation Training Program of Shaanxi Province(No.2490)
文摘The reaction of 5-hydroxyl-7-methoxyflavone(tectochrysin) with bromine obtained 3,6,8-tribromo-5-hydroxy-2,7-dimethoxy-2,3-dihydrochromen-4-one(1), which was characterized by FT-IR, 1 H-NMR, ^(13)C-NMR, elemental analysis and X-ray single-crystal diffraction. Complex 1 belongs to the monoclinic system, space group pbca with a = 9.4673(8), b = 17.9938(15), c = 21.2004(17) ?, V = 3611.5(5) ?~3, Z = 8, μ = 0.6726 mm^(-1), Dc = 1.795 g/cm3, F(000) = 2080, the final R = 0.0358 and wR = 0.0644 with I > 2σ(I). The results show that the addition reaction occurs at the carbon-carbon double bond(C2 and C3) of tectochrysin and 1 belongs to dihydroflavone. The reaction mechanism was discussed and the structure revealed that the crystal structure of 1 is stabilized by intramolecular hydrogen bonds and C–Br···π interactions. The antitumor ability of 1 was evaluated against human leukemia cells(K562), human breast cancer cells(MCF-7) and human lung cancer cells(A549). 1 exhibited potent antitumor activities against human leukemia cells(K562) with the IC50 values of 18.9 μmol/L.
基金supported by the National Key R&D Program of China(Grant No.2017YFB0310500)the National Natural Science Foundation of China(Grant No.61575212)the Key Research Project of the Frontier Science of the Chinese Academy of Sciences(No.QYZDB-SSW-JSC022).
文摘The Yb:Lu_(2)O_(3)precursor made up of spherical particles was synthesized through the co-precipitation method in the water/ethanol solvent.The 5 at% Yb:Lu_(2)O_(3)powder is in the cubic phase after calcination at 1100℃ for 4 h.The powder also consists of spherical nanoparticles with the average particle and grain sizes of 96 and 49 nm,respectively.The average grain size of the pre-sintered ceramic sample is 526 nm and that of the sample by hot isostatic pressing grows to 612 nm.The 1.0 mm-thick sample has an in-line transmittance of 81.6%(theoretical value of 82.2%)at 1100 nm.The largest absorption cross-section at 976 nm is 0.96×1^(0-20)cm^(2) with the emission cross-section at 1033 nm of 0.92×10^(-20)cm^(2) and the gain cross sections are calculated with the smallest population inversion parameter β of 0.059.The highest slope efficiency of 68.7% with the optical efficiency of 65.1% is obtained at 1033.3 nm in quasi-continuous wave(QCW)pumping.In the case of continuous wave(CW)pumping,the highest slope efficiency is 61.0% with the optical efficiency of 54.1%.The obtained laser performance indicates that Yb:Lu_(2)O_(3)ceramics have excellent resistance to thermal load stresses,which shows great potential in high-power solid-state laser applications.
基金Project supported by Programa Nacional de Pos-Doutorado(PNPD/CAPES-086/2013)-Brazil。
文摘In this work we repo rt on structural and spect roscopic properties of Yb^3+doped and Pr^3+/Yb^3+co-doped TeO2-Bi2 O3-ZnO-Li2 O-Nb2 O5(TBZLN)tellurite glasses.Bending and stretching modes of TeO2 and Te-OH bond(strong and weak)were analysed from the deconvolution of observed Raman and FT-IR spectra.Based on the absorption measurements,the energy bands of Yb^3+and Pr^3+ions are assigned.The spectroscopic properties for the radiative transitions of Yb^3+and Pr^3+ions were reported using McCumber and Judd-Ofelt theories.Visible emission bands originating from 3 P1 and 3 P0 to lower lying levels of Pr^3+were registered under 447 nm excitation.The emission band around 1334 nm assigned to the Pr3:1 G4→3 H5 was observed when excited at 980 nm.The stimulated emission cross-section(σemi(λ))and effective linewidth(Δλeff)for the 3 P1→3 H6,3 P1→3 H5,3 P0→3 H6,3 P0→3 F2,3 P1→3 F3,3 P1→3 F4,3 P0→3 F4 and 1 G4→3 H5 transitions of Pr^3+are reported.Upconversion luminescence in Pr^3+/Yb^3+codoped glass upon 980 nm excitation was measured.Possible resonant transfer processes between Yb^3+and Pr^3+ions are presented and discussed.The chromaticity co-ordinates were also evaluated from the visible emission spectra showing that Pr^3+/Yb^3+co-doped glass may be suitable for the development of yellow-orange(λexc=447 nm)and near white light(λexc=980 nm)emitting devices in photonics.
基金the Fundamental Research Funds for the Central Universities(XK1802-6,XK1803-05,XK1902,12060093063)。
文摘A pair of nickel(Ⅱ)complexes monomer and dimer,namely[NiCl2(L)](1)and[Ni2Cl2(L)2(μ-Cl)2](2)(L=2-morpholine-4-yl-4,6-di-pyrazol-1-yl-1,3,5-triazine),were synthesized by using L to react with NiCl2·2 H2 O at 35 and 65℃,respectively.X-ray crystal structures of complexes 1 and 2 were determined.Complex 1 is mononuclear and its nickel(Ⅱ)center resides in a distorted square-pyramidal environment with a NiN3Cl2 donor set,but complex 2 is binuclear and its nickel(Ⅱ)center shows a distorted octahedral geometry with a NiN3Cl3 donor set.In complex 2,two adjacent nickel(Ⅱ)centers are connected by two bridging chloride anions.Complexes 1 and 2 form different three-dimensional supramolecular structures through non-covalent interactions such asπ-πstacking interactions,anion-πinteractions and weak hydrogen bonds.Both complexes were further characterized by thermal gravimetric analyses and spectroscopic methods.
基金Project supported by Shanghai Sailing Program from Science and Technology Committee of Shanghai (21YF1416200)。
文摘Herein,melt-quenching and Er^(3+) doping were used to synthesize fluoride glass specimens with low phonon energies(582 cm^(-1)).These glass specimens exhibit intense 3.1 μm mid-infrared band emission when they are excited by a 980 nm laser diode,achieving a full width at half maximum(FWHM) of about166 nm.This 3.1 μm emission intensity is enhanced by the introduction of ZnF_(2) to the AlF_(3)-based fluoride glass.Up-conversion emission,strong near-infrared emission,and fluorescence lifetime are enhanced to different degrees by increasing the ZnF_(2) content.Moreover,the spectroscopic characteristics of the glass specimens and the highly efficient Er^(3+):~4S_(3/2)→~4F_(9/2) transition's energy transfer mechanism were investigated.The absorption spectra and emission spectra of these aluminum fluoride glass specimens were used to calculate their gain coefficients and maximum cross sections at 1.5 and 3.1 μm.Overall,the spectral properties of these prepared aluminum fluoride glass specimens demonstrate their high potential for use as infrared laser host materials.
基金supported by the National Natural Science Foundation of China(61765002,11647107,51762003,11764004,11764014)the Natural Science Foundation of Jiangxi Province(20171BAB202038,20202ACBL214020,20202ACBL202003,GJJ180753)。
文摘A Yb^(3+):KBaY(MoO_(4))_(3)(Yb^(3+):KBYM)crystal with dimensions of 51 mm×27 mm × 10 mm was successfully grown by the TSSG method.The characteristics of the crystal structure and probability of good optical properties were analyzed.The absorption and emission spectra of Yb^(3+):KBYM crystal exhibit broadened bands,with the maximum absorption cross-sections of 1.17 × 10^(-20),1.44×10^(-20) and 1.37 × 10^(-20) cm^(2) at976 nm for X-,Y-and Z-polarizations,respectively.The corresponding absorption FWHMs are as wide as 77,46 and 55 nm.The well-known re-absorption effect of Yb^(3+) in the crystal is discussed.Two methods,the Fiichtbauer-Ladenburg method(FL)and reciprocity method(RM)were adopted to compute the emission cross-sections and results show a certain discrepancy but the errors are allowable.The laser potentiality of the Yb^(3+):KBYM crystal was also evaluated by calculations of minimum inversion fractionβmin,saturation pump intensity Isat,the minimum pump intensity Imin and gain cross-sections spectra.Laser experiment was carried out and Watt-level continuous wave laser has been realized.Results indicate that the Yb^(3+):KBYM crystal with a disordered structure may be a potential laser media that can be used to generate tunable and ultrashort pulse laser emissions with high quality beam.
