A series of novel luminescent materials, SrZnO2:M (M=Eu3+, or Eu3+ + Li+) have been synthesized by high-temperature solid-state reaction. The structure and luminescence properties of SrZnO2:Eu3+ phosphor were studied ...A series of novel luminescent materials, SrZnO2:M (M=Eu3+, or Eu3+ + Li+) have been synthesized by high-temperature solid-state reaction. The structure and luminescence properties of SrZnO2:Eu3+ phosphor were studied through XRD, photoluminescence and Raman spectroscopy. The excitation spectra show a broad intense band and a number of small peaks corresponding to the inner 4f-shell excitations of Eu3+ (the strongest one is at 395 nm for 7F0-5L6). After SrZnO2:Eu3+ phosphor was co-doped with Li+ ions, its charge transfer band extended to longer wavelengths. This resulted in increase of luminescent quantum efficiency of the sample. SrZnO2:Eu3+,Li+ phosphor can be efficiently excited by longer UV. From the fluorescence spectrum of SrZnO2:Eu3+ phosphor, apart from transition emissions of 5D0 → 7FJ (J=0~4), the transition emissions from 5D1 → 7FJ (J=0~2) have been observed. For the SrZnO2:Eu3+ phosphor, under excitation of UV, the dominant emission is at about 612 nm, due to the 5D0 → 7F2 hypersensitive transition. The incorporation of Li+ ions greatly enhanced the luminescence intensity and made emission peak from 5D0 → 7F2 transition red-shifted.展开更多
Phosphor-in-glass(PiG)is a potential color convertor for high power WLEDs.A novel glass matrix with advanced performance is still a challenge.Recently,Eu^(3+)doped glass matrix has attracted much consideration mainly ...Phosphor-in-glass(PiG)is a potential color convertor for high power WLEDs.A novel glass matrix with advanced performance is still a challenge.Recently,Eu^(3+)doped glass matrix has attracted much consideration mainly due to its red compensation.A new borophosphate matrix to realize Eu^(3+)red light was designed in the Na_(2)O-ZnO-P_(2)O_(5)-B_(2)O_(3)-Eu_(2)O_(3)system.Meanwhile,a series of PiGs composed of different concentrations of Y3Al5O12:Ce phosphor and the matrix were also fabricated by re-sintering.The crystallization of Eu^(3+)based phosphate offers a novel red emission quenching apart from normal concentration quenching in the glass system.No direct energy transfer but only little reabso rption occurs between Eu^(3+)and Ce^(3+)ions.The Ce^(3+)concentration effect is obvious on the electroluminescent color.The optimized color rendering index of 79.7,the CIE coordinates near natural white and the range of CCT from 3943 to 6097 K were obtained for the packaged white light emitting diodes(WLEDs)together with the excellent CCT stability higher than about 97.5%and the quadruple thermal conductivity than that of silicon resin.The work implies borophosphate glass based PiGs with fine transparence and energy conversion efficiency are promising for excellent WLEDs,while the LED by using the PiG sample without any yellow phosphor doped is of high color purity and has a potential use as the 465 nm blue source.展开更多
Excitation and emission spectra of new borate La_2CaB_(10)O_(19) doped Eu^(3+) in VUV-VIS range, high resolution (emission) spectra at room temperature and lifetime of Eu^(3+) were investigated. The emission line at a...Excitation and emission spectra of new borate La_2CaB_(10)O_(19) doped Eu^(3+) in VUV-VIS range, high resolution (emission) spectra at room temperature and lifetime of Eu^(3+) were investigated. The emission line at about 616 nm attributed to the (()~5D_0)-(()~7F_2) transition of Eu^(3+) is the most intense emission of Eu^(3+). The broad band at about 244 nm is originated from charge transition band (CTB) of O^(2-)→Eu^(3+). According to the numbers of spectral lines (()~5D_0)-(()~7F_0) and (()~5D_0)-(()~7F_1) in high-resolution spectrum, Eu^(3+) ions occupy two crystallographic sites. The lifetimes of (()~5D_0)-(()~7F_0) transition of Eu^(3+) of two kinds of lattice sites are individually 2.1 and 2.6 ms, and both are exponential decay. In the VUV excitation spectrum, complicated band between 130 and 170 nm consists of host absorption and f-d transition of Eu^(3+).展开更多
The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances.In this ...The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances.In this paper,a novel hybrid composite based on the layered rare earth hydroxides was successfully prepared by the ion-exchange and intercalation chemical process.The rare earth elements in the composite contain gadolinium(Gd)and europium(Eu)and the molar ratio of Gd to Eu is kept constant at 1.9:0.1.Organic sodium dodecyl sulfonate and dye coumarin-3-carboxyllc acid are simultaneously incorporated into the layered rare earth hydroxides as supporting agent and light-harvesting antenna,respectively.The resulting hybrid layered rare earth hydroxides exhibit the enlarged interlayer distance with about 2.60 nm,and the chemical composition was confirmed through X-ray diffraction,carbon,hydrogen and nitrogen(CHN)elemental analysis,infrared spectroscopy,and thermogravimetric analysis.The layered solid compound shows the characteristic red emission corresponding to the^(5)D_(0)→^(7)F_(2)transition of Eu^(3+)ion,and the luminescence intensity of the optimized compound is greatly enhanced as compared to its corresponding nitrate and the hybrid composite without the introduction of dye molecule.The hybrid layered rare earth hydroxides can be exfoliated into bright colloidal solution,which show superior recognition capability to Cu^(2+)ion with the distinct luminescence quenching.The large quenching constant(1.4×10^(4)L/mol)and low detection limit(0.35μmol/L)are achieved for Cu^(2+)ion,implying a"turn-off"fluorescent sensor for Cu^(2+)detection.Moreover,a transparent film was prepared based on the colloidal solution and displays the typical red emission in folded shape.The new hybrid compound with enhanced luminescence and excellent photofunctional performances is expected to be applied in the fields of fluorescent sensing and flexible optical devices.展开更多
The Eu^3＋/Ag co-doped rare earth disilicate Y2Si2O7 microcrystal was synthesized by sol-gel method. Through controlling the thermal treatment process of YzSi2OT：EU3＋/Ag precursor, various phases （amorphous, α, ...The Eu^3＋/Ag co-doped rare earth disilicate Y2Si2O7 microcrystal was synthesized by sol-gel method. Through controlling the thermal treatment process of YzSi2OT：EU3＋/Ag precursor, various phases （amorphous, α, β, γ, δ） were prepared. White light emis- sion was observed under UV light excitation in the samples heavily doped with Ag. The white light was realized by combining the intense red emission of Eu3＋, the green emission attributed to the very small molecule-like, non-plasmonic Ag particles （ML-Ag-particles）, and the blue emission due to Ag ions. Results demonstrated that Eu3＋/Ag co-doped Y2Si207 microcrystal could be potentially applied as white light emission phosphors for UV LED chips.展开更多
We reported on the high pressure luminescence spectra of polycrystalline Eu-doped GaN material synthesized in the reaction between alloys of gallium, bismuth and europium in ammonia atmosphere. The integrated luminesc...We reported on the high pressure luminescence spectra of polycrystalline Eu-doped GaN material synthesized in the reaction between alloys of gallium, bismuth and europium in ammonia atmosphere. The integrated luminescence intensity of the dominant Eu3＋ ion transition （5D0→^7F2） at 622 nm increased approximately one order of rnagnitude whereas its spectral position and line width did not change significantly between ambient and 6.8 GPa pressure, respectively. Moreover, material was characterized with photo- and cathodo-luminescence, and photoluminescence excitation spectra at different temperatures. It was found that the Eu3＋ ions occupying substitutional Ga site created different centers which could be effectively excited with above band gap excitation and from excitons resonantly photoexcited at the I2 bound exciton energy. Furthermore, the less efficient Eu3＋ ions excitation path existed through intrinsic impurities and defeels generating shallow energy levels in the forbidden gap. It was proposed that reduction of the thermal quenching and consequent enhancement of Eu3＋ ion emission intensity resulted from stronger localization of bound exciton on RESI trap induced by applied pressure.展开更多
Because of industrial interest, techniques to prepare a thermally stabilized active alumina have been developed. Ionic probe has been widely used in the studying of structure and function on biomacromolecules. In this...Because of industrial interest, techniques to prepare a thermally stabilized active alumina have been developed. Ionic probe has been widely used in the studying of structure and function on biomacromolecules. In this paper, the phase transition in alumina at differ-ent sintering temperatures was first studied by Eu3+ ion fluorescent probe. The XRD, FTIR and fluorescence spectra measurements show that γ-phase is dominated in alumina at below 1000℃; the mixed γ-and phases in the sample are produced at 1 100 ℃;but α-phase in alumina is dominated at 1 200 ℃. It is shown in FTIR spectra that the peak of Eu-O stretching vibration increases dramatically at 1 200 ℃ Meanwhile, fluorescence spectra in-dicate that the peak of 613 nm is weakned gradually whereas the peak of 617 nm is strength-ened in 5D0-F2 supersensitive transition of Eu3+ when the sintering temperature increases.However, the peak of 5D0-7F4 transition splits evidently at 1 200 ℃ because of the decreasing of symmetry in Eu3+ coordination site.展开更多
文摘A series of novel luminescent materials, SrZnO2:M (M=Eu3+, or Eu3+ + Li+) have been synthesized by high-temperature solid-state reaction. The structure and luminescence properties of SrZnO2:Eu3+ phosphor were studied through XRD, photoluminescence and Raman spectroscopy. The excitation spectra show a broad intense band and a number of small peaks corresponding to the inner 4f-shell excitations of Eu3+ (the strongest one is at 395 nm for 7F0-5L6). After SrZnO2:Eu3+ phosphor was co-doped with Li+ ions, its charge transfer band extended to longer wavelengths. This resulted in increase of luminescent quantum efficiency of the sample. SrZnO2:Eu3+,Li+ phosphor can be efficiently excited by longer UV. From the fluorescence spectrum of SrZnO2:Eu3+ phosphor, apart from transition emissions of 5D0 → 7FJ (J=0~4), the transition emissions from 5D1 → 7FJ (J=0~2) have been observed. For the SrZnO2:Eu3+ phosphor, under excitation of UV, the dominant emission is at about 612 nm, due to the 5D0 → 7F2 hypersensitive transition. The incorporation of Li+ ions greatly enhanced the luminescence intensity and made emission peak from 5D0 → 7F2 transition red-shifted.
基金The Natural Science Foundation of China(50972061)the Zhejiang Provincial Natural Science Foundation of China(R4100364,Z4110072)K.C.Wong Magna Fund in Ningbo University
基金Project supported by the Joint Funds of the National Natural Science Foundation of China(U1932160)the National Natural Science Foundation of China(51605272)。
文摘Phosphor-in-glass(PiG)is a potential color convertor for high power WLEDs.A novel glass matrix with advanced performance is still a challenge.Recently,Eu^(3+)doped glass matrix has attracted much consideration mainly due to its red compensation.A new borophosphate matrix to realize Eu^(3+)red light was designed in the Na_(2)O-ZnO-P_(2)O_(5)-B_(2)O_(3)-Eu_(2)O_(3)system.Meanwhile,a series of PiGs composed of different concentrations of Y3Al5O12:Ce phosphor and the matrix were also fabricated by re-sintering.The crystallization of Eu^(3+)based phosphate offers a novel red emission quenching apart from normal concentration quenching in the glass system.No direct energy transfer but only little reabso rption occurs between Eu^(3+)and Ce^(3+)ions.The Ce^(3+)concentration effect is obvious on the electroluminescent color.The optimized color rendering index of 79.7,the CIE coordinates near natural white and the range of CCT from 3943 to 6097 K were obtained for the packaged white light emitting diodes(WLEDs)together with the excellent CCT stability higher than about 97.5%and the quadruple thermal conductivity than that of silicon resin.The work implies borophosphate glass based PiGs with fine transparence and energy conversion efficiency are promising for excellent WLEDs,while the LED by using the PiG sample without any yellow phosphor doped is of high color purity and has a potential use as the 465 nm blue source.
文摘Excitation and emission spectra of new borate La_2CaB_(10)O_(19) doped Eu^(3+) in VUV-VIS range, high resolution (emission) spectra at room temperature and lifetime of Eu^(3+) were investigated. The emission line at about 616 nm attributed to the (()~5D_0)-(()~7F_2) transition of Eu^(3+) is the most intense emission of Eu^(3+). The broad band at about 244 nm is originated from charge transition band (CTB) of O^(2-)→Eu^(3+). According to the numbers of spectral lines (()~5D_0)-(()~7F_0) and (()~5D_0)-(()~7F_1) in high-resolution spectrum, Eu^(3+) ions occupy two crystallographic sites. The lifetimes of (()~5D_0)-(()~7F_0) transition of Eu^(3+) of two kinds of lattice sites are individually 2.1 and 2.6 ms, and both are exponential decay. In the VUV excitation spectrum, complicated band between 130 and 170 nm consists of host absorption and f-d transition of Eu^(3+).
基金Project supported by the National Natural Science Foundation of China(51972097)。
文摘The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances.In this paper,a novel hybrid composite based on the layered rare earth hydroxides was successfully prepared by the ion-exchange and intercalation chemical process.The rare earth elements in the composite contain gadolinium(Gd)and europium(Eu)and the molar ratio of Gd to Eu is kept constant at 1.9:0.1.Organic sodium dodecyl sulfonate and dye coumarin-3-carboxyllc acid are simultaneously incorporated into the layered rare earth hydroxides as supporting agent and light-harvesting antenna,respectively.The resulting hybrid layered rare earth hydroxides exhibit the enlarged interlayer distance with about 2.60 nm,and the chemical composition was confirmed through X-ray diffraction,carbon,hydrogen and nitrogen(CHN)elemental analysis,infrared spectroscopy,and thermogravimetric analysis.The layered solid compound shows the characteristic red emission corresponding to the^(5)D_(0)→^(7)F_(2)transition of Eu^(3+)ion,and the luminescence intensity of the optimized compound is greatly enhanced as compared to its corresponding nitrate and the hybrid composite without the introduction of dye molecule.The hybrid layered rare earth hydroxides can be exfoliated into bright colloidal solution,which show superior recognition capability to Cu^(2+)ion with the distinct luminescence quenching.The large quenching constant(1.4×10^(4)L/mol)and low detection limit(0.35μmol/L)are achieved for Cu^(2+)ion,implying a"turn-off"fluorescent sensor for Cu^(2+)detection.Moreover,a transparent film was prepared based on the colloidal solution and displays the typical red emission in folded shape.The new hybrid compound with enhanced luminescence and excellent photofunctional performances is expected to be applied in the fields of fluorescent sensing and flexible optical devices.
基金Project supported by the National Natural Science Foundation of China(11074232,11274288,21002097,11304300)the National Basic Research Program of China(2011CB932801,2012CB933702)Ministry of Education of China(20123402110034)
文摘The Eu^3＋/Ag co-doped rare earth disilicate Y2Si2O7 microcrystal was synthesized by sol-gel method. Through controlling the thermal treatment process of YzSi2OT：EU3＋/Ag precursor, various phases （amorphous, α, β, γ, δ） were prepared. White light emis- sion was observed under UV light excitation in the samples heavily doped with Ag. The white light was realized by combining the intense red emission of Eu3＋, the green emission attributed to the very small molecule-like, non-plasmonic Ag particles （ML-Ag-particles）, and the blue emission due to Ag ions. Results demonstrated that Eu3＋/Ag co-doped Y2Si207 microcrystal could be potentially applied as white light emission phosphors for UV LED chips.
基金supported by the Polish Committee for Scientific Research (PBZ/MEiN/01/2006/39)
文摘We reported on the high pressure luminescence spectra of polycrystalline Eu-doped GaN material synthesized in the reaction between alloys of gallium, bismuth and europium in ammonia atmosphere. The integrated luminescence intensity of the dominant Eu3＋ ion transition （5D0→^7F2） at 622 nm increased approximately one order of rnagnitude whereas its spectral position and line width did not change significantly between ambient and 6.8 GPa pressure, respectively. Moreover, material was characterized with photo- and cathodo-luminescence, and photoluminescence excitation spectra at different temperatures. It was found that the Eu3＋ ions occupying substitutional Ga site created different centers which could be effectively excited with above band gap excitation and from excitons resonantly photoexcited at the I2 bound exciton energy. Furthermore, the less efficient Eu3＋ ions excitation path existed through intrinsic impurities and defeels generating shallow energy levels in the forbidden gap. It was proposed that reduction of the thermal quenching and consequent enhancement of Eu3＋ ion emission intensity resulted from stronger localization of bound exciton on RESI trap induced by applied pressure.
文摘Because of industrial interest, techniques to prepare a thermally stabilized active alumina have been developed. Ionic probe has been widely used in the studying of structure and function on biomacromolecules. In this paper, the phase transition in alumina at differ-ent sintering temperatures was first studied by Eu3+ ion fluorescent probe. The XRD, FTIR and fluorescence spectra measurements show that γ-phase is dominated in alumina at below 1000℃; the mixed γ-and phases in the sample are produced at 1 100 ℃;but α-phase in alumina is dominated at 1 200 ℃. It is shown in FTIR spectra that the peak of Eu-O stretching vibration increases dramatically at 1 200 ℃ Meanwhile, fluorescence spectra in-dicate that the peak of 613 nm is weakned gradually whereas the peak of 617 nm is strength-ened in 5D0-F2 supersensitive transition of Eu3+ when the sintering temperature increases.However, the peak of 5D0-7F4 transition splits evidently at 1 200 ℃ because of the decreasing of symmetry in Eu3+ coordination site.
