SrGa-2S-4∶Ce blue TFEL device with a novel structure was prepared by electron beam evaporation. The dielectric constant of insulator layer in this structure is far less than that in the conventional structure, so the...SrGa-2S-4∶Ce blue TFEL device with a novel structure was prepared by electron beam evaporation. The dielectric constant of insulator layer in this structure is far less than that in the conventional structure, so the hot-electrons can be accelerated in SiO-2 layers. The stable TFEL with good chromaticity was achieved and the basic characteristics were investigated.展开更多
Cr^(3+)-Doped phosphors are attracting attention for broadband near-infrared(NIR)applications.However,some mechanisms are still unclear due to the entangled crystallographic site occupancy and changeable valence of ch...Cr^(3+)-Doped phosphors are attracting attention for broadband near-infrared(NIR)applications.However,some mechanisms are still unclear due to the entangled crystallographic site occupancy and changeable valence of chromium in the host lattice.In this study,a particular gallium SrGa_(4)O_(7)(SGO)was employed as a host for chromium doping.The characteristic broadband NIR emission of Cr^(3+)ions in octahedral sites centered in the range of 650 to 1200 nm with a full width at half maximum(FWHM)of 140 nm and an internal quantum efficiency of more than 46%was observed,although there were only four and seven coordination sites in the SGO lattice.The distorted octahedron in the SGO lattice was generated due to the transition from Ga-O tetrahedron to the octahedron with the doping of Cr^(3+)ions,and it was regulated by the cation regulation of Ca2+substituted for Sr2+ions in the lattice.In particular,the characteristic Cr^(4+)ion emission between 1200 and 1700 nm with an FWHM at~215 nm was observed in phosphors for the first time.This study provides new cogitation for the Cr^(3+)ion site occupation in the host lattice and a new idea to develop broadband NIR emission phosphors.展开更多
The electro optical characteristics of SrS∶Ce and SrGa 2S 4∶Ce as two kinds of hopeful blue TFEL phosphors have been intensively investigated. The color purity of SrGa 2S 4∶Ce is better than that of SrS∶Ce. ...The electro optical characteristics of SrS∶Ce and SrGa 2S 4∶Ce as two kinds of hopeful blue TFEL phosphors have been intensively investigated. The color purity of SrGa 2S 4∶Ce is better than that of SrS∶Ce. In this paper, the influence of Ga 3+ on photoluminescence (PL) characteristics of Ce 3+ is first reported. Ga 2S 3 was doped into SrS, then sintered. The emission spectra shift obviously towards short wavelength range with increase of Ga 3+ concentration. At the same time, the relative intensity of the excitation peaks corresponding to the interband absorption of SrS reduces, and the excitation efficiency corresponding to the transition from the ground state to the excited state of Ce 3+ ion increases. The ligand field around Ce 3+ is changed by doped Ga 3+ . The ionicity of the substituted become stronger and Ce 3+ -Ce 3+ interaction become weaker. These are favorite to blue emission.展开更多
文摘SrGa-2S-4∶Ce blue TFEL device with a novel structure was prepared by electron beam evaporation. The dielectric constant of insulator layer in this structure is far less than that in the conventional structure, so the hot-electrons can be accelerated in SiO-2 layers. The stable TFEL with good chromaticity was achieved and the basic characteristics were investigated.
基金unnan Joint Fund(U1902222)National Natural Science Foundation of China(no.11774138,11664022,51862020)Foundation of Yunnan Province(2019HC016).
文摘Cr^(3+)-Doped phosphors are attracting attention for broadband near-infrared(NIR)applications.However,some mechanisms are still unclear due to the entangled crystallographic site occupancy and changeable valence of chromium in the host lattice.In this study,a particular gallium SrGa_(4)O_(7)(SGO)was employed as a host for chromium doping.The characteristic broadband NIR emission of Cr^(3+)ions in octahedral sites centered in the range of 650 to 1200 nm with a full width at half maximum(FWHM)of 140 nm and an internal quantum efficiency of more than 46%was observed,although there were only four and seven coordination sites in the SGO lattice.The distorted octahedron in the SGO lattice was generated due to the transition from Ga-O tetrahedron to the octahedron with the doping of Cr^(3+)ions,and it was regulated by the cation regulation of Ca2+substituted for Sr2+ions in the lattice.In particular,the characteristic Cr^(4+)ion emission between 1200 and 1700 nm with an FWHM at~215 nm was observed in phosphors for the first time.This study provides new cogitation for the Cr^(3+)ion site occupation in the host lattice and a new idea to develop broadband NIR emission phosphors.
文摘The electro optical characteristics of SrS∶Ce and SrGa 2S 4∶Ce as two kinds of hopeful blue TFEL phosphors have been intensively investigated. The color purity of SrGa 2S 4∶Ce is better than that of SrS∶Ce. In this paper, the influence of Ga 3+ on photoluminescence (PL) characteristics of Ce 3+ is first reported. Ga 2S 3 was doped into SrS, then sintered. The emission spectra shift obviously towards short wavelength range with increase of Ga 3+ concentration. At the same time, the relative intensity of the excitation peaks corresponding to the interband absorption of SrS reduces, and the excitation efficiency corresponding to the transition from the ground state to the excited state of Ce 3+ ion increases. The ligand field around Ce 3+ is changed by doped Ga 3+ . The ionicity of the substituted become stronger and Ce 3+ -Ce 3+ interaction become weaker. These are favorite to blue emission.
