The excitation wavelength-dependent and-independent emissions are two crucial fluorescent properties of carbon dots(CDs).However,CDs reported till date exhibit only one of these properties,which limits their practical...The excitation wavelength-dependent and-independent emissions are two crucial fluorescent properties of carbon dots(CDs).However,CDs reported till date exhibit only one of these properties,which limits their practical applications.Herein,dual-property carbon dots(DCDs)with both the excitation wavelength-dependent and-independent emissions were synthesized via a facile onestep solvothermal method using 4-(2-pyridylazo)-resorcinol as the carbon precursor.The multi-functional applications of the resulting DCDs were also evaluated.The asprepared DCDs exhibited not only excellent monodispersity,high photostability,and storage stability,but also low toxicity,good biocompatibility,and cellular bioimaging capability.In addition,the DCDs exhibited excitation-dependent emission photoluminescence under low excitation wavelengths.The DCDs exhibited good Fe3+detection by quenching the blue emission fluorescence and showed a relatively low Fe3+detection limit of 0.067 lmol·L-1 based on three times signal-to-noise criteria(R2=0.99).Furthermore,the DCDs showed excitation-independent emission at low excitation wavelengths and exhibited red emission at about 598 nm to avoid damage to the body.These results demonstrate the excellent bioimaging properties of the DCDs.Owing to their dual PL properties,the as-prepared DCDs exhibited multi-functional applications:Fe3+detection and A549 cell bioimaging.These results will be helpful in developing novel CDs for applications in various fields.展开更多
In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was ev...In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was evaluated by degrading methylene blue (MB) solution. The results indicated that TiO2 crystalline size was reduced and phase transformation of anatase to rutile was suppressed as the content of doped Nd3+ ion increased in the co-doped TiO2. The UV-vis spectra of co-doped TiO2 seemed to simply overlay two spectra of single metal doped TiO2, and had significantly increased absorbance in the ranges of 400～500 nm, 565～600 nm and 730～765 nm as compared to pure TiO2. The photocatalytic activity of co-doped TiO2 was obviously enhanced, and raised about 30% compared to that of pure TiO2 as doped Nd3+ content was 0.15% and Fe3+ content was 0.05%, respectively. The enhanced catalytic activity was attributed to a synergistic effect of two doped ions, where doped Fe3+ ion inhibited the recombination of photogenerated electron and hole, and Nd3+ ion brought more surface carboxyl to promote the degradation reaction.展开更多
Lanthanum-bearing iron lithium borate glass is a quaternary system for oxide glasses and was prepared via the melt-quenching method.The present article correlates the structure,optical,ligand field and M?ssbauer data ...Lanthanum-bearing iron lithium borate glass is a quaternary system for oxide glasses and was prepared via the melt-quenching method.The present article correlates the structure,optical,ligand field and M?ssbauer data on iron lithium borate glass co ntaining La^(3+).The density was measured,while the molar volume was calculated.Other physical parameters are well-described.With increasing the La_(2)O_(3) content within the glass network,infrared spectra analysis reveals structural modifications such as the increase in BO_(4) units and the decline in both BO_(3) units and NBO bonds content.Furthermore,optical absorption spectra were measured.The absorption spectra disclose a plethora of electronic transitions that are related to Fe^(3+)in tetrahedral and octahedral sites,however,Fe^(2+)phase is not observed in optical spectra,but it has a clear signature in M?ssbauer spectra.Besides,the glass absorption edges undergo a clear blue shift,reflecting an increased band gap energy(1.96-2.28 eV).The decline in NBO bonds justifies this trend.Bewitchingly,the values of crystal field splitting are increased,while the values of Racah parameters are decreased.This trend is justified by the decline in NBO bonds and increases electron localization around Fe cations.M?ssbauer spectra confirm the existence of Fe^(3+)in tetrahedral and octahedral sites,while Fe^(2+)exists in only a tetrahedral state.With increasing La_(2)O_(3) content,the isomer shift of Fe^(3+)in tetrahedral sites changes to be 0.312-0.329 mm/s,while the isomer shift of octahedral Fe^(3+)is 0.424-0.456 mm/s.These findings coincide with optical data.While the isomer shift of tetrahedral Fe^(2+)is 0.902-0.911 mm/s.Our results of structural,optical and ligand field associated with M?ssbauer spectra open more vistas toward the utility of these samples in the optics realm.展开更多
In this work, a new porous Zrobased metal-organic framework （MOF） with a large Brunner-Emmet-Teller （BET） surface area was prepared by the solvothermal method using 4,4＇-（naphthalene-1,4-diyl）dibenzoic acid （N...In this work, a new porous Zrobased metal-organic framework （MOF） with a large Brunner-Emmet-Teller （BET） surface area was prepared by the solvothermal method using 4,4＇-（naphthalene-1,4-diyl）dibenzoic acid （NDDA） as the organic ligand, and the luminescent detection performance was studied systematically. The experiments comb- ing with computations indicate that the as-synthesized material can sensitively and selectively detect nitro explo- sives and metal ions, especially for 2,4,6-trinitrophenol （TNP） and Fe3＋, due to the possible electron transfer from inorganic moieties to organic moieties with naphthalene part. Interestingly, owing to its high porosity and large sur- face area, this Zr-MOF showed quick luminescent response time （in 1 min） for TNP and Fe3＋. The results obtained may provide useful information for the design of MOFs with the large permanent porosity in sensing applications for large molecules in the future.展开更多
基金the National Natural Science Foundation of China(No.81660708)the Natural Science Foundation of Jiangsu Province of China(No.BK20171389)+2 种基金the Qinglan Project of Young Academic Leaders of Jiangsu Provincethe Key Project of Science and Technology of Tibet(No.2015XZ01G70)the Key Project of Tibetan Medical Administration(No.2017005)。
文摘The excitation wavelength-dependent and-independent emissions are two crucial fluorescent properties of carbon dots(CDs).However,CDs reported till date exhibit only one of these properties,which limits their practical applications.Herein,dual-property carbon dots(DCDs)with both the excitation wavelength-dependent and-independent emissions were synthesized via a facile onestep solvothermal method using 4-(2-pyridylazo)-resorcinol as the carbon precursor.The multi-functional applications of the resulting DCDs were also evaluated.The asprepared DCDs exhibited not only excellent monodispersity,high photostability,and storage stability,but also low toxicity,good biocompatibility,and cellular bioimaging capability.In addition,the DCDs exhibited excitation-dependent emission photoluminescence under low excitation wavelengths.The DCDs exhibited good Fe3+detection by quenching the blue emission fluorescence and showed a relatively low Fe3+detection limit of 0.067 lmol·L-1 based on three times signal-to-noise criteria(R2=0.99).Furthermore,the DCDs showed excitation-independent emission at low excitation wavelengths and exhibited red emission at about 598 nm to avoid damage to the body.These results demonstrate the excellent bioimaging properties of the DCDs.Owing to their dual PL properties,the as-prepared DCDs exhibited multi-functional applications:Fe3+detection and A549 cell bioimaging.These results will be helpful in developing novel CDs for applications in various fields.
基金Project supported by Beijing Excellent Talents Training Fund (20061D0502200299)
文摘In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was evaluated by degrading methylene blue (MB) solution. The results indicated that TiO2 crystalline size was reduced and phase transformation of anatase to rutile was suppressed as the content of doped Nd3+ ion increased in the co-doped TiO2. The UV-vis spectra of co-doped TiO2 seemed to simply overlay two spectra of single metal doped TiO2, and had significantly increased absorbance in the ranges of 400～500 nm, 565～600 nm and 730～765 nm as compared to pure TiO2. The photocatalytic activity of co-doped TiO2 was obviously enhanced, and raised about 30% compared to that of pure TiO2 as doped Nd3+ content was 0.15% and Fe3+ content was 0.05%, respectively. The enhanced catalytic activity was attributed to a synergistic effect of two doped ions, where doped Fe3+ ion inhibited the recombination of photogenerated electron and hole, and Nd3+ ion brought more surface carboxyl to promote the degradation reaction.
文摘Lanthanum-bearing iron lithium borate glass is a quaternary system for oxide glasses and was prepared via the melt-quenching method.The present article correlates the structure,optical,ligand field and M?ssbauer data on iron lithium borate glass co ntaining La^(3+).The density was measured,while the molar volume was calculated.Other physical parameters are well-described.With increasing the La_(2)O_(3) content within the glass network,infrared spectra analysis reveals structural modifications such as the increase in BO_(4) units and the decline in both BO_(3) units and NBO bonds content.Furthermore,optical absorption spectra were measured.The absorption spectra disclose a plethora of electronic transitions that are related to Fe^(3+)in tetrahedral and octahedral sites,however,Fe^(2+)phase is not observed in optical spectra,but it has a clear signature in M?ssbauer spectra.Besides,the glass absorption edges undergo a clear blue shift,reflecting an increased band gap energy(1.96-2.28 eV).The decline in NBO bonds justifies this trend.Bewitchingly,the values of crystal field splitting are increased,while the values of Racah parameters are decreased.This trend is justified by the decline in NBO bonds and increases electron localization around Fe cations.M?ssbauer spectra confirm the existence of Fe^(3+)in tetrahedral and octahedral sites,while Fe^(2+)exists in only a tetrahedral state.With increasing La_(2)O_(3) content,the isomer shift of Fe^(3+)in tetrahedral sites changes to be 0.312-0.329 mm/s,while the isomer shift of octahedral Fe^(3+)is 0.424-0.456 mm/s.These findings coincide with optical data.While the isomer shift of tetrahedral Fe^(2+)is 0.902-0.911 mm/s.Our results of structural,optical and ligand field associated with M?ssbauer spectra open more vistas toward the utility of these samples in the optics realm.
基金Financial support by the National Key Basic Re- search Programof China （＂973＂） （No. 2013CB733503）, the National Natural Science Foundation of China （Nos. 21606007, 21136001 and 21536001） and the Funda- mental Research Funds for the Central Universities （No. ZY1509） is greatly appreciated.
文摘In this work, a new porous Zrobased metal-organic framework （MOF） with a large Brunner-Emmet-Teller （BET） surface area was prepared by the solvothermal method using 4,4＇-（naphthalene-1,4-diyl）dibenzoic acid （NDDA） as the organic ligand, and the luminescent detection performance was studied systematically. The experiments comb- ing with computations indicate that the as-synthesized material can sensitively and selectively detect nitro explo- sives and metal ions, especially for 2,4,6-trinitrophenol （TNP） and Fe3＋, due to the possible electron transfer from inorganic moieties to organic moieties with naphthalene part. Interestingly, owing to its high porosity and large sur- face area, this Zr-MOF showed quick luminescent response time （in 1 min） for TNP and Fe3＋. The results obtained may provide useful information for the design of MOFs with the large permanent porosity in sensing applications for large molecules in the future.
