SnO2 nanocrystal and rare-earth Eu^3＋ ion co-doped SiO2 thin films are prepared by sol-gel and spin coating methods. The formation of tetragonal rutile structure SnO2 nanocrystals with a uniform distribution is confi...SnO2 nanocrystal and rare-earth Eu^3＋ ion co-doped SiO2 thin films are prepared by sol-gel and spin coating methods. The formation of tetragonal rutile structure SnO2 nanocrystals with a uniform distribution is confirmed by X-ray diffraction and transmission electron microscopy. Fourier transform infrared spectroscopy is used to investigate the densities of the hydroxyl groups, and it is found that the emission intensity from the 5Do-TF2 transitions of the Eu^3＋ ions is enhanced by two orders of magnitude due to energy transfer from the oxygen-vacancy-related defects of the SnO2 nanocrystals to nearby Eu^3＋ ions. The influences of the amounts of Sn and the post-annealing temperatures are systematically evaluated to further understand the mechanism of energy transfer. The luminescence intensity ratio of Eu^3＋ ions from electric dipole transition and magnetic dipole transition indicate the different probable locations of Eu^3＋ ions in the sol-gel thin film, which are further discussed based on temperature-dependent photoluminescence measurements.展开更多
Er^3＋ ions doped chalcohalide glasses with the composition of 56GeS2-24Ga2S3-20KCl were fabricated by a melt-quenching method.Under 800 nm laser excitation,strong green emissions centered at 525 nm and 550 nm and wea...Er^3＋ ions doped chalcohalide glasses with the composition of 56GeS2-24Ga2S3-20KCl were fabricated by a melt-quenching method.Under 800 nm laser excitation,strong green emissions centered at 525 nm and 550 nm and weak red emission centered at 660 nm were observed,which were assigned to ^2H11/2→^4I15/2,^4S3/2→^4I15/2,and ^4F9/2→^4I15/2 transitions,respectively.The intensity reached maximum when the Er^3＋ ions concentration was 0.1 mol%.The possible upconversion luminescence mechanism was proposed from the discussion on the above results as well as the results of lifetimes of the metastable ^4I13/2 level and local environment of Er^3＋ ions.It is found that chalcohalide glass can be good host materials for upconversion luminescence.展开更多
A new and practical fluorescence temperature detecting system based on fluorescence intensity ratio was proposed . The background theory of fluorescence intensity-ratio method was presented simply. And the characters ...A new and practical fluorescence temperature detecting system based on fluorescence intensity ratio was proposed . The background theory of fluorescence intensity-ratio method was presented simply. And the characters of rare earth doped samples were detailed. The erbium-doped fiber was chosen as the sensing element. The energy levels of 2H11/2 and 4S3/2 are responsible for the emission of radiation at approximately 530 and 555 nm. The erbium-doped (960 ppm) fiber of length 20 cm and core diameter 3.2μm was used as the sensing part. A silica photodiode transfers the fluorescence signal to electric signal, then the ratio of the average of the two different signals was calculated by the computer and the temperature was obtained. The ratio R of the intensity resulting from the transition between the two levels varies proportionly with temperature interval from 293 K to 373 K. The sensitivity of the sensor is approximately 0.05 K-1.展开更多
YVO4：Er^3＋,Yb^3＋ with varying Yb^3＋ concentrations were prepared by a precipitation method.The results of X-ray diffraction （XRD） show that all the samples have a tetragonal zircon structure; the calculated aver...YVO4：Er^3＋,Yb^3＋ with varying Yb^3＋ concentrations were prepared by a precipitation method.The results of X-ray diffraction （XRD） show that all the samples have a tetragonal zircon structure; the calculated average crystallite sizes are in the range of 14-22 nm.The lattice constants and cell volume of the samples decrease slightly with the increase in Yb^3＋ concentration.The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation.The strong green emission is observed,which is attributed to the 2^H11/2→4I15/2 and 4^S3/2→4^I15/2 transitions of Er^3＋,and the red emission peaks in 650-675 nm can be ignored.The emission intensity for the sample depends on the Yb^3＋concentration.These results reveal that the upconversion processes of YVO4：Er^3＋,Yb^3＋ are related to the structure and the doping Yb^3＋ concentration of the sample.展开更多
Due to their superior fluorescence,phosphorescence,and catalytic capabilities,carbon dots(CDs),an emerging class of fluorescent carbon nanomaterials,have a wide range of potential applications.The properties of CDs ha...Due to their superior fluorescence,phosphorescence,and catalytic capabilities,carbon dots(CDs),an emerging class of fluorescent carbon nanomaterials,have a wide range of potential applications.The properties of CDs have recently been controlled extensively by heteroatom doping.Boron atoms have been effectively doped into the structure of CDs due to their similar size to carbon atoms and excellent electron-absorbing ability to further improve the performance of CDs.In this review,we summarize the research progress of boron-doped CDs in recent years from the aspects of doping strategies,effects of boron doping on different performances of CDs and applications.Starting from the two aspects of single boron doping and boron and other atom co-doping,from different precursor materials to different synthesis methods,the doping strategies of boron-doped CDs are reviewed in detail.Then,the effects of boron doping on the fluorescence,phosphorescence and catalytic performance of CDs and applications of boron-doped CDs in optical sensors,information encryption and anti-counterfeiting are discussed.Finally,we further provide a prospect towards the future development of boron-doped CDs.展开更多
Photo-responsive room-temperature phosphorescent(RTP)materials have garnered significant interest due to the advantages of rapid response,spatiotemporal control,and contactless precision manipulation.However,the devel...Photo-responsive room-temperature phosphorescent(RTP)materials have garnered significant interest due to the advantages of rapid response,spatiotemporal control,and contactless precision manipulation.However,the development of such materials remains in its infancy,underscoring the importance of exploiting novel and efficient light-responsive RTP molecules.In this work,three phenothiazine derivatives of TPA-PTZ,TPA-2PTZ,and TPA-3PTZ were successfully synthesized via the Buchwald-Hartwig C—N coupling reaction.By embedding these molecules as RTP guests into polymethyl methacrylate(PMMA)matrix,photo-induced RTP properties were realized.Upon sustained UV irradiation,there was an enhancement of 19 times in the quantum yield to reach a value of 5.68%.Remarkably,these materials exhibit superior alongside robust light and thermal stability,maintaining high phosphorescence intensity even after prolonged UV exposure(irradiation for>200 s by a 365 nm UV lamp with the power of 500μW·cm-2)or at higher temperature up to 75℃.The outstanding properties of these photo-induced RTP materials make them promising candidates for applications in information encryption,anti-counterfeiting,and advanced optical materials.展开更多
This study fully investigated the vacuum ultraviolet excitation spectra of pure and rare-earth（RE=Eu, Tb and Dy）-doped A2Zr（PO4）2（A=Li, Na and K） phosphors. The synthesized Na and Li compounds were characterized...This study fully investigated the vacuum ultraviolet excitation spectra of pure and rare-earth（RE=Eu, Tb and Dy）-doped A2Zr（PO4）2（A=Li, Na and K） phosphors. The synthesized Na and Li compounds were characterized by XRD showing two new types of phases after indexation. Although these three pure compounds had different crystal structures, they exhibited similar luminescence properties. For Eu3＋-activated samples, the broad excitation band centered at 217 nm could be attributed to the CT transition between O2–（2p6） and Eu3＋ ions. For Tb3＋-doped samples, two groups of f-d transitions were observed, where a strong broad band at 221 nm was due to the spin-allowed f-d transition. Energy transfer from O2– to Dy3＋was not observed in Dy3＋-doped phosphors, probably because it overlapped considerably with the CT transition from O2– to Zr4＋ at 187 nm.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61036001)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK2010010)the Fundamental Research Funds for the Central Universities of China(Grant Nos.1112021001 and 1116021003)
文摘SnO2 nanocrystal and rare-earth Eu^3＋ ion co-doped SiO2 thin films are prepared by sol-gel and spin coating methods. The formation of tetragonal rutile structure SnO2 nanocrystals with a uniform distribution is confirmed by X-ray diffraction and transmission electron microscopy. Fourier transform infrared spectroscopy is used to investigate the densities of the hydroxyl groups, and it is found that the emission intensity from the 5Do-TF2 transitions of the Eu^3＋ ions is enhanced by two orders of magnitude due to energy transfer from the oxygen-vacancy-related defects of the SnO2 nanocrystals to nearby Eu^3＋ ions. The influences of the amounts of Sn and the post-annealing temperatures are systematically evaluated to further understand the mechanism of energy transfer. The luminescence intensity ratio of Eu^3＋ ions from electric dipole transition and magnetic dipole transition indicate the different probable locations of Eu^3＋ ions in the sol-gel thin film, which are further discussed based on temperature-dependent photoluminescence measurements.
基金supported by National Nature Science Foundation of China (No.60808024)the Fundamental Research Funds for the Central Universities (Wuhan University of Technology)
文摘Er^3＋ ions doped chalcohalide glasses with the composition of 56GeS2-24Ga2S3-20KCl were fabricated by a melt-quenching method.Under 800 nm laser excitation,strong green emissions centered at 525 nm and 550 nm and weak red emission centered at 660 nm were observed,which were assigned to ^2H11/2→^4I15/2,^4S3/2→^4I15/2,and ^4F9/2→^4I15/2 transitions,respectively.The intensity reached maximum when the Er^3＋ ions concentration was 0.1 mol%.The possible upconversion luminescence mechanism was proposed from the discussion on the above results as well as the results of lifetimes of the metastable ^4I13/2 level and local environment of Er^3＋ ions.It is found that chalcohalide glass can be good host materials for upconversion luminescence.
文摘A new and practical fluorescence temperature detecting system based on fluorescence intensity ratio was proposed . The background theory of fluorescence intensity-ratio method was presented simply. And the characters of rare earth doped samples were detailed. The erbium-doped fiber was chosen as the sensing element. The energy levels of 2H11/2 and 4S3/2 are responsible for the emission of radiation at approximately 530 and 555 nm. The erbium-doped (960 ppm) fiber of length 20 cm and core diameter 3.2μm was used as the sensing part. A silica photodiode transfers the fluorescence signal to electric signal, then the ratio of the average of the two different signals was calculated by the computer and the temperature was obtained. The ratio R of the intensity resulting from the transition between the two levels varies proportionly with temperature interval from 293 K to 373 K. The sensitivity of the sensor is approximately 0.05 K-1.
基金supported by the Educational Department Project of Liaoning Province(No.2005319)
文摘YVO4：Er^3＋,Yb^3＋ with varying Yb^3＋ concentrations were prepared by a precipitation method.The results of X-ray diffraction （XRD） show that all the samples have a tetragonal zircon structure; the calculated average crystallite sizes are in the range of 14-22 nm.The lattice constants and cell volume of the samples decrease slightly with the increase in Yb^3＋ concentration.The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation.The strong green emission is observed,which is attributed to the 2^H11/2→4I15/2 and 4^S3/2→4^I15/2 transitions of Er^3＋,and the red emission peaks in 650-675 nm can be ignored.The emission intensity for the sample depends on the Yb^3＋concentration.These results reveal that the upconversion processes of YVO4：Er^3＋,Yb^3＋ are related to the structure and the doping Yb^3＋ concentration of the sample.
基金the Youth Talent Program Startup Foundation of Qufu Normal University(No.602601)the Natural Science Foundation of Rizhao(No.RZ2021ZR37)。
文摘Due to their superior fluorescence,phosphorescence,and catalytic capabilities,carbon dots(CDs),an emerging class of fluorescent carbon nanomaterials,have a wide range of potential applications.The properties of CDs have recently been controlled extensively by heteroatom doping.Boron atoms have been effectively doped into the structure of CDs due to their similar size to carbon atoms and excellent electron-absorbing ability to further improve the performance of CDs.In this review,we summarize the research progress of boron-doped CDs in recent years from the aspects of doping strategies,effects of boron doping on different performances of CDs and applications.Starting from the two aspects of single boron doping and boron and other atom co-doping,from different precursor materials to different synthesis methods,the doping strategies of boron-doped CDs are reviewed in detail.Then,the effects of boron doping on the fluorescence,phosphorescence and catalytic performance of CDs and applications of boron-doped CDs in optical sensors,information encryption and anti-counterfeiting are discussed.Finally,we further provide a prospect towards the future development of boron-doped CDs.
文摘Photo-responsive room-temperature phosphorescent(RTP)materials have garnered significant interest due to the advantages of rapid response,spatiotemporal control,and contactless precision manipulation.However,the development of such materials remains in its infancy,underscoring the importance of exploiting novel and efficient light-responsive RTP molecules.In this work,three phenothiazine derivatives of TPA-PTZ,TPA-2PTZ,and TPA-3PTZ were successfully synthesized via the Buchwald-Hartwig C—N coupling reaction.By embedding these molecules as RTP guests into polymethyl methacrylate(PMMA)matrix,photo-induced RTP properties were realized.Upon sustained UV irradiation,there was an enhancement of 19 times in the quantum yield to reach a value of 5.68%.Remarkably,these materials exhibit superior alongside robust light and thermal stability,maintaining high phosphorescence intensity even after prolonged UV exposure(irradiation for>200 s by a 365 nm UV lamp with the power of 500μW·cm-2)or at higher temperature up to 75℃.The outstanding properties of these photo-induced RTP materials make them promising candidates for applications in information encryption,anti-counterfeiting,and advanced optical materials.
基金supported by National Natural Science Foundation of China(11104298,5033250,U1332202)Innovation Program of Shanghai Institute of Ceramics(Y34ZC130G)
文摘This study fully investigated the vacuum ultraviolet excitation spectra of pure and rare-earth（RE=Eu, Tb and Dy）-doped A2Zr（PO4）2（A=Li, Na and K） phosphors. The synthesized Na and Li compounds were characterized by XRD showing two new types of phases after indexation. Although these three pure compounds had different crystal structures, they exhibited similar luminescence properties. For Eu3＋-activated samples, the broad excitation band centered at 217 nm could be attributed to the CT transition between O2–（2p6） and Eu3＋ ions. For Tb3＋-doped samples, two groups of f-d transitions were observed, where a strong broad band at 221 nm was due to the spin-allowed f-d transition. Energy transfer from O2– to Dy3＋was not observed in Dy3＋-doped phosphors, probably because it overlapped considerably with the CT transition from O2– to Zr4＋ at 187 nm.
