The Ce^3+ and Eu^2+ ions codoped calcium zinc chlorosilicate Ca_8Zn(SiO_4)_4Cl_2 phosphors have been synthesized for the first time. The diffuse reflection, excitation and emission spectra of Ca_8Zn(SiO_4)_4Cl_2∶Ce^3...The Ce^3+ and Eu^2+ ions codoped calcium zinc chlorosilicate Ca_8Zn(SiO_4)_4Cl_2 phosphors have been synthesized for the first time. The diffuse reflection, excitation and emission spectra of Ca_8Zn(SiO_4)_4Cl_2∶Ce^3+, Eu^2+ have been measured at room temperature. The luminescence sensitizaiton of Eu^2+ by Ce^3+ inCa_8Zn(SiO_4)_4Cl_2∶Ce^3+, Eu^2+ has been expounded under the excitation of ultraviolet light and the efficient nonradiative energy transfer from Ce^3+ to Eu^2+ in this system is confirmed.展开更多
The new phosphor calcium magnesium chlorosilicate, codoped with Eu^2+ and Dy^3+, was synthesized with the help of the high temperature solid state reaction in reducing atmosphere. The excitation and emission spectra...The new phosphor calcium magnesium chlorosilicate, codoped with Eu^2+ and Dy^3+, was synthesized with the help of the high temperature solid state reaction in reducing atmosphere. The excitation and emission spectra were very similar to that of Ca8Mg(SiO4)4Cl2 :Eu^2+, and the Dy^3+ concentration influenced the emission intensity of this phosphor. The intensity of Eu^2+ and Dy^3+ codoped CMSC was stronger than that of Eu^2+ singly doped CMSC. The emission spectrum of the Dy^3+ ion overlapped the absorption band of the Eu^2+ ion, indicating that an energy transfer from Dy^3+ to Eu^2+ took place in CMSC:Eu^2+, Dy^3+ phosphor. The mechanism of the energy transfer from Dy^3+ tO Eu^2+, in this phosphor, might be resonant energy transfer.展开更多
According to the Van Uitert experimental equation, crystal-lattice environment of Eu^(2+) in the Sr_4Si_3O_8Cl_4 crystal was discussed. By adding Mg^(2+) to the host lattice, Sr_(4- x )Mg_ x Si_3O_8Cl_4∶Eu^(2+) was s...According to the Van Uitert experimental equation, crystal-lattice environment of Eu^(2+) in the Sr_4Si_3O_8Cl_4 crystal was discussed. By adding Mg^(2+) to the host lattice, Sr_(4- x )Mg_ x Si_3O_8Cl_4∶Eu^(2+) was synthesized and the emission peak shifted from blue-green (488 nm) to blue-violet (411 nm) with the increase of amount of the magnesium which replaced the strontium. By analyzing the spectra of Sr_(4- x )Mg_ x Si_3O_8Cl_4∶Eu^(2+) the two Eu^(2+) emission centers were found because of the change of crystal-lattice environment in the host and the crystal structure was obtained by X-ray diffraction data.展开更多
Calcium magnesium chlorosilicate doped by europium, Ca8Mg(SiO4)4Cl2: Eu^2+, was prepared by the solid state reaction at high temperature. The compound obtained is pure Ca8Mg(SiO4)4Cl2 phase with cubic structure....Calcium magnesium chlorosilicate doped by europium, Ca8Mg(SiO4)4Cl2: Eu^2+, was prepared by the solid state reaction at high temperature. The compound obtained is pure Ca8Mg(SiO4)4Cl2 phase with cubic structure. Its average particle size is 5 μm, and it has good dispersity and morphological form. The excitation spectrum of Ca8Mg(SiO4)4Cl2: Eu^2+ is a wide band, which covers from 270 to 480 nm. The emission spectrum is also a wide band peaked at 510 nm. The luminescent intensity reaches to the maximum when the concentration of Eu^2 + is 2%. The wavelength of emission and excitation of the phosphor with various Eu^2 + contents keeps constant. This spectrum range matches violet and blue LED chips very well, and its strong luminescence intensity is suitable for a green phosphor of tricolor phosphor of white light LED.展开更多
The green phosphor for white LED, Ca 8Mg(SiO 4) 4Cl 2∶Eu 2+, Mn 2+, was synthesized by high temperature solid state reaction under reducing atmosphere. During the process of the phosphor prepared, the excess Ca...The green phosphor for white LED, Ca 8Mg(SiO 4) 4Cl 2∶Eu 2+, Mn 2+, was synthesized by high temperature solid state reaction under reducing atmosphere. During the process of the phosphor prepared, the excess CaCl 2 can improve the intensity of emission. The experimental results indicate that there is an effective energy transfer from Eu 2+ to Mn 2+in Ca 8Mg(SiO 4) 4Cl 2 host. This kind of energy transfer may be due to resonance transfer, and this energy transfer is limited.展开更多
The fluorescent characteristic and emission spectra of Eu^(2+) in the cubic structure Ca_8Zn(SiO_4)_4Cl_2 with three kinds of cation sites is reported.The influence of temperature,Eu^(2+) concentra- tion and excitatio...The fluorescent characteristic and emission spectra of Eu^(2+) in the cubic structure Ca_8Zn(SiO_4)_4Cl_2 with three kinds of cation sites is reported.The influence of temperature,Eu^(2+) concentra- tion and excitation conditions on fluorescent properties of Eu^(2+) are studied at 77 and 298 K.The coordination number of Eu^(2+) at different sites is obtained.The green and red emission bands arise from Eu_(2+) ions locating on eight- and six- coordinated inequivalent sites respectively.展开更多
Ca8Mg(SiO4)4Cl2:Eu2+ phosphor doped with Sr2+ cation for Ca2+ partially, was synthesized by solid-slate reaction at high temperature under reducing atmosphere, and its luminescent properties were investigated. The exp...Ca8Mg(SiO4)4Cl2:Eu2+ phosphor doped with Sr2+ cation for Ca2+ partially, was synthesized by solid-slate reaction at high temperature under reducing atmosphere, and its luminescent properties were investigated. The experimental results indicate that the emission intensity of the phosphor increases after being doped with a few amount of Sr2+ ion. The emission peak of the phosphor blue shift to about 464 nm when the phosphor is doped with large quantity of Sr2+ ions. The excitation spectrum indicates that the phosphor can be well excited by UV and blue light from 300 to 460 nm, and the phosphor was fitted well for the excitation by UV or blue-LED.展开更多
Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route, respectively. Their structures and photoluminescence properties were ...Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route, respectively. Their structures and photoluminescence properties were comparatively investigated. It was found that the mixture phases of Sr2MgSi2O7 and SrF2 were obtained when a part of Sr2+ in Sr2LiSiO4F was replaced by some amount of Mg2+ in order to design the possible SrMgLiSiO4F:Eu2+ phosphor. Based on the photoluminescence analysis, Sr2LiSiO4F:Eu2+ phosphor exhibited a green broad emission band of main peak at 513 nm under the excitation of 365 nm, while the Sr2MgSi2O7:Eu2+ and SrMgLiSiO4F:Eu2+ phosphor showed blue emission centered at 467 nm. The temperature dependent photoluminescence properties and room temperature decay time for the three kinds of phosphors were also discussed in this paper.展开更多
文摘The Ce^3+ and Eu^2+ ions codoped calcium zinc chlorosilicate Ca_8Zn(SiO_4)_4Cl_2 phosphors have been synthesized for the first time. The diffuse reflection, excitation and emission spectra of Ca_8Zn(SiO_4)_4Cl_2∶Ce^3+, Eu^2+ have been measured at room temperature. The luminescence sensitizaiton of Eu^2+ by Ce^3+ inCa_8Zn(SiO_4)_4Cl_2∶Ce^3+, Eu^2+ has been expounded under the excitation of ultraviolet light and the efficient nonradiative energy transfer from Ce^3+ to Eu^2+ in this system is confirmed.
基金Project supported by the National Natural Science Foundation of China (50372086)MOST of China (2006CB601104)
文摘The new phosphor calcium magnesium chlorosilicate, codoped with Eu^2+ and Dy^3+, was synthesized with the help of the high temperature solid state reaction in reducing atmosphere. The excitation and emission spectra were very similar to that of Ca8Mg(SiO4)4Cl2 :Eu^2+, and the Dy^3+ concentration influenced the emission intensity of this phosphor. The intensity of Eu^2+ and Dy^3+ codoped CMSC was stronger than that of Eu^2+ singly doped CMSC. The emission spectrum of the Dy^3+ ion overlapped the absorption band of the Eu^2+ ion, indicating that an energy transfer from Dy^3+ to Eu^2+ took place in CMSC:Eu^2+, Dy^3+ phosphor. The mechanism of the energy transfer from Dy^3+ tO Eu^2+, in this phosphor, might be resonant energy transfer.
文摘According to the Van Uitert experimental equation, crystal-lattice environment of Eu^(2+) in the Sr_4Si_3O_8Cl_4 crystal was discussed. By adding Mg^(2+) to the host lattice, Sr_(4- x )Mg_ x Si_3O_8Cl_4∶Eu^(2+) was synthesized and the emission peak shifted from blue-green (488 nm) to blue-violet (411 nm) with the increase of amount of the magnesium which replaced the strontium. By analyzing the spectra of Sr_(4- x )Mg_ x Si_3O_8Cl_4∶Eu^(2+) the two Eu^(2+) emission centers were found because of the change of crystal-lattice environment in the host and the crystal structure was obtained by X-ray diffraction data.
文摘Calcium magnesium chlorosilicate doped by europium, Ca8Mg(SiO4)4Cl2: Eu^2+, was prepared by the solid state reaction at high temperature. The compound obtained is pure Ca8Mg(SiO4)4Cl2 phase with cubic structure. Its average particle size is 5 μm, and it has good dispersity and morphological form. The excitation spectrum of Ca8Mg(SiO4)4Cl2: Eu^2+ is a wide band, which covers from 270 to 480 nm. The emission spectrum is also a wide band peaked at 510 nm. The luminescent intensity reaches to the maximum when the concentration of Eu^2 + is 2%. The wavelength of emission and excitation of the phosphor with various Eu^2 + contents keeps constant. This spectrum range matches violet and blue LED chips very well, and its strong luminescence intensity is suitable for a green phosphor of tricolor phosphor of white light LED.
文摘The green phosphor for white LED, Ca 8Mg(SiO 4) 4Cl 2∶Eu 2+, Mn 2+, was synthesized by high temperature solid state reaction under reducing atmosphere. During the process of the phosphor prepared, the excess CaCl 2 can improve the intensity of emission. The experimental results indicate that there is an effective energy transfer from Eu 2+ to Mn 2+in Ca 8Mg(SiO 4) 4Cl 2 host. This kind of energy transfer may be due to resonance transfer, and this energy transfer is limited.
文摘The fluorescent characteristic and emission spectra of Eu^(2+) in the cubic structure Ca_8Zn(SiO_4)_4Cl_2 with three kinds of cation sites is reported.The influence of temperature,Eu^(2+) concentra- tion and excitation conditions on fluorescent properties of Eu^(2+) are studied at 77 and 298 K.The coordination number of Eu^(2+) at different sites is obtained.The green and red emission bands arise from Eu_(2+) ions locating on eight- and six- coordinated inequivalent sites respectively.
基金Project supported by the National Natural Science Foundation of China (50372086)MOST of China (2006CB601104)
文摘Ca8Mg(SiO4)4Cl2:Eu2+ phosphor doped with Sr2+ cation for Ca2+ partially, was synthesized by solid-slate reaction at high temperature under reducing atmosphere, and its luminescent properties were investigated. The experimental results indicate that the emission intensity of the phosphor increases after being doped with a few amount of Sr2+ ion. The emission peak of the phosphor blue shift to about 464 nm when the phosphor is doped with large quantity of Sr2+ ions. The excitation spectrum indicates that the phosphor can be well excited by UV and blue light from 300 to 460 nm, and the phosphor was fitted well for the excitation by UV or blue-LED.
基金Project supported by the National Natural Science Foundation of China (51002146, 20876002, 20976002)Natural Science Foundation of Beijing (2082009, 2091002)+1 种基金the Ph.D. Programs Foundation of Ministry of Education of China (20090022120002)the Fundamental Research Funds for the Central Universities (2010ZY35)
文摘Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route, respectively. Their structures and photoluminescence properties were comparatively investigated. It was found that the mixture phases of Sr2MgSi2O7 and SrF2 were obtained when a part of Sr2+ in Sr2LiSiO4F was replaced by some amount of Mg2+ in order to design the possible SrMgLiSiO4F:Eu2+ phosphor. Based on the photoluminescence analysis, Sr2LiSiO4F:Eu2+ phosphor exhibited a green broad emission band of main peak at 513 nm under the excitation of 365 nm, while the Sr2MgSi2O7:Eu2+ and SrMgLiSiO4F:Eu2+ phosphor showed blue emission centered at 467 nm. The temperature dependent photoluminescence properties and room temperature decay time for the three kinds of phosphors were also discussed in this paper.