共查询到20条相似文献,搜索用时 31 毫秒
1.
《Ceramics International》2016,42(4):4642-4647
Tunable up-conversion luminescent material KY(MoO4)2: Yb3+, Ln3+ (Ln=Er, Tm, Ho) has been synthesized by a typical hydrothermal process. Under 980 nm laser diode (LD) excitation, the emission intensity and the corresponding luminescence colors of KY(MoO4)2: Yb3+, Ln3+ (Ln=Er, Tm, Ho) have been investigated in detail. The energy transfer from the Yb3+ sensitizer to Ho3+, Er3+ and Tm3+ activators plays an important role in the development of color-tunable single- phased phosphors. The emission intensity keep balance through control of the Ho3+ co-doping concentrations, white light was experimentally shown at KY(MoO4)2: 20 mol% Yb3+, 0.8 mol% Er3+, 0.5 mol% Tm3+, 1.0 mol% Ho3+ phosphor with further calcination at 800 °C for 4 h under 980 nm laser excitation. The color tunability, high quality of white light and high intensity of the emitted signal make these up-conversion (UC) phosphors excellent candidates for applications in solid-state lighting. 相似文献
2.
Baozhu Yang Zhiping Yang Yufeng Liu Fachun Lu Panlai Li Yanmin Yang Xu Li 《Ceramics International》2012,38(6):4895-4900
A series of red-emitting phosphors Eu3+-doped Sr3Y(PO4)3 have been successfully synthesized by conventional solid-state reaction, and its photoluminescence properties have been investigated. The excitation spectra reveal strong excitation bands at 392 nm, which match well with the popular emissions from near-UV light-emitting diode chips. The emission spectra of Sr3Y(PO4)3:Eu3+ phosphors exhibit peaks associated with the 5D0 → 7FJ (J = 0, 1, 2, 3, 4) transitions of Eu3+ and have dominating emission peak at 612 nm under 392 nm excitation. The integral intensity of the emission spectra of Sr3Y0.94(PO4)3:0.06Eu3+ phosphors excited at 392 nm is about 3.4 times higher than that of Y2O3:Eu3+ commercial red phosphor. The Commission Internationale de l’Eclairage chromaticity coordinates, the quantum efficiencies and decay times of the phosphors excited under 392 nm are also investigated. The experimental results indicate that the Eu3+-doped Sr3Y(PO4)3 phosphors are promising red-emitting phosphors pumped by near-UV light. 相似文献
3.
Yangyi Xu Xiaohui Wang Yunge Wei Yuanxi Liu Guifang Li 《International Journal of Applied Ceramic Technology》2021,18(5):1570-1581
CaGd2(WO4)4:Eu3+ phosphors with controllable morphology were synthesized via the hydrothermal method. The influences of pH value, reaction time and Eu3+ concentration on the crystal structure, morphology, and photoluminescence properties of CaGd2(WO4)4:Eu3+ were studied. The pure tetragonal structure CaGd2(WO4)4 is obtained when the pH value is 8 and 9. Furthermore, by altering the pH value of the reaction solution, the morphologies of the CaGd2(WO4)4:Eu3+ phosphors evolve from spindle-shaped grains to tetragonal plate-like grains and finally to aggregated bulk particles. Under the 394 nm excitation, the phosphors display a bright red emission corresponding to the characteristic 4f-4f transitions of Eu3+, and the intensity of emission peaks depends mainly on the pH value, the reaction time, and the Eu3+ concentration. The optimum photoluminescence performance is achieved for CaGd2-x(WO4)4:xEu3+ (x = 1) phosphor synthesized at pH = 8 under the reaction time of 16 h. Finally, the thermal stability of the phosphors is analyzed at different ambient temperatures. 相似文献
4.
《Ceramics International》2017,43(2):1937-1942
A series of emission-tunable Ca3SiO4Cl2:Bi3+, Li+, Eun+(n =2, 3) (CSC:Bi3+, Li+, Eun+) phosphors have been synthesized via sol-gel method. The X-ray diffraction results indicate that the as-synthesized phosphors crystallize in a low temperature phase with the space group of P21/c. Energy transfer from Bi3+ to Eu3+/Eu2+ exists in CSC:Bi3+, Li+, Eun+ phosphors. Under the excitation of 327 or 365 nm, the Ca2.98−ySiO4Cl2:0.01Bi3+, 0.01Li+, yEun+(y=0.0001–0.002) phosphors show an intense green emission band around 505 nm, while under the excitation of 264 nm, three emission bands centered around 396 nm (Bi3+), 505 nm (Eu2+) and 614 nm (Eu3+) are observed and tunable colors from blue-violet to green or white are achieved in these phosphors by varying the content of Eu. White-light emission with the color coordinate (0.312, 0.328) is obtained in Ca2.978SiO4Cl2:0.01Bi3+, 0.01Li+, 0.002Eun+(n =2, 3). Based on these results, the as-prepared CSC:Bi3+, Li+, Eu2+, Eu3+ phosphors can act as color-tunable and single-phase white emission phosphors for potential applications in UV-excited white LEDs. 相似文献
5.
《Ceramics International》2016,42(15):16499-16504
Monoclinic KLa(MoO4)2:Eu3+ microarchitectures with different morphologies were synthesized by an EDTA-assisted hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR) and photoluminescence (PL) spectrometer. It was found that the amounts of EDTA and the pH values of precursor solution have crucial influences on the structure, morphology and size of the obtained samples, respectively. Under 270 nm excitation, Eu3+ doped KLa(MoO4)2 samples showed red emission centered at 618 nm which attributed to 5D0→7F2 transition of Eu3+. The dependence of luminescence intensity on different morphologies were discussed in detailed. With further annealing treatment, the emission intensities of peanut-like samples increased amazingly. Moreover, the lifetime of the annealed samples were calculated. The significantly enhanced photoluminescence performances indicate that the as-annealed samples are promising phosphors which can be used for white light-emitting diodes (WLEDs). 相似文献
6.
Zhi-Wei Zhang Xin-Yuan Sun Dan-Dan Jia Shi-Tao Song Jian-Ping Zhang Shao-Fei Wang 《Ceramics International》2013,39(4):3965-3970
Tunable full color emissive LiSr3.99?xDy0.01(BO3)3:xEu3+ (0≤x≤0.09) phosphors peaked at 481 nm (blue), 574 nm (yellow), 592 nm (orange), and 617 nm (red) were synthesized in air by high temperature solid-state reaction route. The as-synthesized phosphors were characterized by X-ray powder diffraction (XRD), photoluminescence excitation (PLE) and photoluminescence (PL) spectra. The PLE spectra in the range from 200 to 500 nm include an Eu–O charge transfer band (CTB) and several 4f–4f transition peaks of Dy3+ and Eu3+, indicating its potential application in white light emitting diodes (LEDs). The effect of Eu3+ concentration on the emission intensity of LiSr3.99?xDy0.01(BO3)3:xEu3+ phosphors was investigated in detail and the optical concentration is found to be x=0.005. The CIE chromaticity coordinates for LiSr3.99?xDy0.01(BO3)3:xEu3+ phosphors are simulated. With an increase in Eu3+ ion concentration, the chromaticity color coordinates can be tuned efficiently from the border of greenish white region to its equal-energy white light point, and eventually to red region. All the results imply that the studied LiSr3.99?xDy0.01(BO3)3:xEu3+ phosphors could be potentially used as white LEDs. 相似文献
7.
《Ceramics International》2016,42(10):11687-11691
In this paper, a series of novel luminescent Sr10−x(SiO4)3(SO4)3O:xEu2+ phosphors with apatite structure were synthesized by a high temperature solid-state reaction. The phase structure, photoluminescence (PL) properties, as well as the PL thermal stability were investigated. Sr9.92(SiO4)3(SO4)3O:0.08Eu2+ phosphor exhibits better thermal quenching resistance, retaining the luminance of 66.55% at 150 °C compared with that at 25 °C. The quenching concentration of Eu2+ in Sr10(SiO4)3(SO4)3O was about 0.08 (mol) with the dipole–quadrupole interaction. The Sr10−x(SiO4)3(SO4)3O:xEu2+ phosphors exhibited a broad-band green emission at 538 nm upon excitation at 396 nm. The results indicate that Sr10−x(SiO4)3(SO4)3O:xEu2+ phosphors have potential applications as near UV-convertible phosphors for white-light UV LEDs. 相似文献
8.
《Ceramics International》2016,42(6):6891-6898
A series of single-phase white-light-emitting phosphors, Eu2+-activated Ba3GdNa(PO4)3F phosphors were synthesized by solid-state reactions. The crystal structure of Ba3GdNa(PO4)3F was been identified by Rietveld refinement of X-ray diffraction pattern. The Eu2+-activated Ba3GdNa(PO4)3F phosphors exhibit broad excitation spectra from 250 to 420 nm, which matched well with the n-UV LED chips. Under the excitation of 365 nm, the emission spectrum almost covered the entire visible region including two emission bands peaked at 472 nm and 640 nm. Three different Eu2+ emission centers in Ba3GdNa(PO4)3F:Eu2+ phosphor were confirmed by their fluorescence decay lifetimes. The optimal concentration of Eu2+ in Ba3GdNa(PO4)3F:xEu2+ was 3 mol% and the corresponding concentration quenching mechanism was verified to be exchange coupling interaction. Furthermore, the white light-emitting diode fabricated with Ba3GdNa(PO4)3F:0.05Eu2+ phosphor and a 370 nm UV chip has a CIE of (0.3267, 0.2976) with a color-rendering index of 78.4 at the CCT of 5287 K. 相似文献
9.
Photoluminescent properties and site occupation preference in Bi3+, Eu3+ doped CaY4(SiO4)3O phosphor
《Ceramics International》2016,42(11):12971-12980
Bi3+, Eu3+ doped CaY4(SiO4)3O phosphors were synthesized through high temperature solid state reaction. Their photoluminescent properties were investigated and site occupation preference of Bi3+ in cationic sites was analyzed. The structure of CaY4(SiO4)3O is characterized by three non-equivalent cationic sites with different coordination and cation-oxygen distances. By means of dielectric theory of the chemical bond for complex crystals, several kinds of chemical bond parameters like fractional covalence of CaY4(SiO4)3O were calculated and integrated to yield environmental factor he. According to quantitative equations between the transition energy of Bi3+ and environmental factor he, the excitation bands at 308 and 226 nm were assigned to 1S0→3P1 transition of Bi3+ in Y(6h) and Y(4f) site, respectively. Another excitation band centered at 210 nm should be the overlap of Bi3+ A-band in Ca site and C-band in Y(6h) site. Optical band gap of pure CYSO was calculated using Kubelka–Munk method from diffuse reflectance spectra. Red emission can be realized in CaY4(SiO4)3O:Bi3+, Eu3+ under UV light excitation because of efficient energy transfer from Bi3+ to Eu3+ and decay behaviors of Bi3+ and Eu3+ emission were investigated. Without optimization, the internal quantum efficiency of CYSO:2%Bi3+, 7%Eu3+ at 310 and 393 nm excitations were 31.563%, 74.252%, respectively. 相似文献
10.
《Ceramics International》2016,42(9):11099-11103
Tb3+ions activated Ba4La6O(SiO4)6 (BLSO:Tb3+) phosphors were synthesized by a citrate sol-gel method. The X-ray diffraction pattern confirmed their oxyapatite structure. The field-emission scanning electron microscope image established that the BLSO:Tb3+phosphor particles were closely-packed and acquired irregular shapes. The photoluminescence (PL) excitation spectra of BLSO:Tb3+phosphors showed intense f–d transitions along with low intense peaks corresponding to the f–f transitions of Tb3+ions in the lower energy region. The PL emission spectra displayed the characteristic emission bands of Tb3+ions, and the optimized concentrations were found to be at 1 and 6 mol% for blue and green emission peaks, respectively. The cathodoluminescece (CL) spectra exhibited a similar behavior that was observed in the PL spectra except the intensity variations in the blue and green regions. The CL spectra of the BLSO:6 mol% Tb3+phosphor unveiled accelerating voltage induced luminescent properties. 相似文献
11.
《Ceramics International》2016,42(16):18536-18546
In the present paper, an investigation on the structural and photoluminescence (PL) properties of SrGd2O4:Eu3+ ceramic phosphors synthesized by homogeneous precipitation method followed by combustion process has been reported. The samples, annealed at 1200 °C, were crystallized into orthorhombic phase without any impurities. Microscopic studies revealed the irregular morphology of the obtained ceramic phosphor particles having sizes in the range of 0.3–3 µm. The characteristic photoluminescence properties and decay curves were studied in detail as a function of Eu3+ concentration and temperature. The Eu3+ doped ceramic samples illuminated with UV light revealed the characteristic red luminescence corresponding to 5D0→7FJ transitions of Eu3+. The concentration quenching phenomenon of Eu3+ ions in the present host, analyzed in the light of ion-ion interaction, indicated multipolar interaction between Eu3+ ions. Finally, the intensity parameters (Ω2, Ω4) and various radiative properties such as stimulated emission cross-section (σe), gain band-width (σe×Δλeff) and optical gain (σe×τexp) of Eu3+ in the SrGd2O4 ceramic phosphors have been calculated by using Judd-Ofelt theory. The present phosphor system exhibited efficient red emission with high red color purity (95%) and adequate thermal stability even at 200 °C. Present research broadly indicated the suitability of SrGd2O4:Eu3+ ceramic phosphor for display applications. 相似文献
12.
The Sm3+-activated CaGd2(MoO4)4 phosphors were prepared through a sol-gel reaction route. From the results of excitation spectrum, three-dimensional emission spectra and contour lines, it was confirmed that the near-ultraviolet (NUV) light was the proper excitation light source for the synthesized phosphors. Under 405 nm irradiation, the luminescent behaviors of the studied samples were revealed to be dependent on the Sm3+ ion concentration and its optimal value of 0.03 mol was obtained. Through theoretical analysis, it is evident that the dipole-dipole interaction can be responsible for the involved concentration quenching mechanism in the final products and the critical distance was 39.7 Å. Moreover, the temperature-dependent emission spectra demonstrated that the studied samples had admirable thermal stability and the activation energy was decided to be 0.21 eV. Furthermore, the internal quantum efficiency of the Sm3+-activated CaGd2(MoO4)4 phosphors was found to be 21.6%. Finally, to explore the practical applications of obtained compounds for indoor illumination, a white light-emitting diode (WLED) device which contained a NUV chip, prepared phosphors, and commercial blue-emitting and green-emitting phosphors was packaged. The packaged WLEDs device can emit dazzling white light with satisfied color coordinate of (0.305, 0.318), proper color rendering index (82.6), and correlated color temperature (7069 K). 相似文献
13.
《Ceramics International》2017,43(17):15107-15114
A series of eulytite-type Sr3Y1-x(PO4)3:xEu3+ (x = 0–0.13) and Sr3-yY(PO4)3:yEu2+ (y = 0–0.10) phosphors were successfully synthesized via gel-combustion and subsequent calcination in O2 and Ar/H2 atmospheres at 1250 °C, respectively. Detailed crystal structure analysis via Rietveld refinement showed that the phosphors were crystallized in the cubic system (space group I-43d, No. 220), in which the Eu3+ and Eu2+ activators reside at the Y3+ and Sr2+ sites, respectively. The trivalent Eu3+ ions (CN = 6) exhibited typical narrow-band luminescence via intra-4f6 transitions, with the red emission at ~ 615 nm being dominant (5D0 → 7F2 transition, FWHM = 15.9 ± 0.2 nm). The divalent Eu2+ ions (CN = 6 and 9) showed broad-band luminescence ranging from light-blue to blue via 4f65d1 → 4f7 transitions (FWHM = 115 ± 2 nm). The optimal Eu3+ and Eu2+ concentrations were determined to be 10 at% (x = 0.10) and 7 at% (y = 0.07), respectively, and the mechanisms of concentration quenching were discussed. The excitation/emission properties, fluorescence decay kinetics, CIE chromaticity, and particularly the rarely addressed thermal stability of the phosphors were investigated in detail. 相似文献
14.
Qinxue Tang Yangting Wu Kehui Qiu Wentao Zhang Junlan Wang 《Ceramics International》2018,44(6):6192-6200
In this study, a series of red-emitting Ca3Sr3(VO4)4:Eu3+ phosphors co-doped with La3+ was prepared using the combustion method. The microstructures, morphologies, and photoluminescence properties of the phosphors were investigated. All Ca3Sr3(VO4)4:Eu3+, La3+ samples synthesized at temperatures greater than 700 ℃ exhibited the same standard rhombohedral structure of Ca3Sr3(VO4)4. Furthermore, the Ca3Sr3(VO4)4:Eu3+, La3+ phosphor was effectively excited by near-ultraviolet light of 393 nm and blue light of 464 nm. The strong excitation peak at 464 nm corresponded to the 7F0→5D2 electron transition of Eu3+. The strong emission peak observed at 619 nm corresponded to the 5D0→7F2 electron transition of Eu3+. Co-doping with La3+ significantly improved the emission intensity of Ca3Sr3(VO4)4:Eu3+ red phosphors. The optimum luminescence of the phosphor was observed at Eu3+ and La3+ concentrations of 5% and 6%, respectively. Moreover, co-doping with La3+ also improved the fluorescence lifetime and thermal stability of the Ca3Sr3(VO4)4:Eu3+ phosphor. The CIE chromaticity coordinate of Ca3Sr3(VO4)4:0.05Eu3+, 0.06La3+ was closer to the NTSC standard for red phosphors than those of other commercial phosphors; moreover, it had greater color purity than that of all the samples tested. The red emission intensity of Ca3Sr3(VO4)4:0.05Eu3+, 0.06La3+ at 619 nm was ~1.53 times that of Ca3Sr3(VO4)4:0.05Eu3+ and 2.63 times that of SrS:Eu2+. The introduction of charge compensators could further increase the emission intensity of Ca3Sr3(VO4)4:Eu3+, La3+ red phosphors. The phosphors synthesized herein are promising red-emitting phosphors for applications in white light-emitting diodes under irradiation by blue chips. 相似文献
15.
Microwave Sol–Gel Synthesis of CaGd2(MoO4)4:Er3+/Yb3+ Phosphors and Their Upconversion Photoluminescence Properties
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Chang Sung Lim Victor Atuchin Aleksandr Aleksandrovsky Maxim Molokeev Aleksandr Oreshonkov 《Journal of the American Ceramic Society》2015,98(10):3223-3230
CaGd2(MoO4)4:Er3+/Yb3+ phosphors with the doping concentrations of Er3+ and Yb3+ (x = Er3+ + Yb3+, Er3+ = 0.05, 0.1, 0.2, and Yb3+ = 0.2, 0.45) have been successfully synthesized by the microwave sol–gel method, and the crystal structure refinement and upconversion photoluminescence properties have been investigated. The synthesized particles, being formed after heat‐treatment at 900°C for 16 h, showed a well‐crystallized morphology. Under the excitation at 980 nm, CaGd2(MoO4)4:Er3+/Yb3+ particles exhibited strong 525 and 550‐nm emission bands in the green region and a weak 655‐nm emission band in the red region. The Raman spectrum of undoped CaGd2(MoO4)4 revealed about 15 narrow lines. The strongest band observed at 903 cm?1 was assigned to the ν1 symmetric stretching vibration of MoO4 tetrahedrons. The spectra of the samples doped with Er and Yb obtained under 514.5 nm excitation were dominated by Er3+ luminescence preventing the recording Raman spectra of these samples. Concentration quenching of the erbium luminescence at 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions in the CaGd2(MoO4)4:Er3+/Yb3+ crystal structure was established to be approximately at the 10 at.% doping level. 相似文献
16.
《Ceramics International》2015,41(4):5525-5530
A series of single-phase Eu3+, Tb3+, Bi3+ co-doped LaPO4 phosphors were synthesized by solid-state reaction at 800 °C. Crystal structures of the phosphors were investigated by X-ray diffraction (XRD). A monoclinic phase was confirmed. The excitation (PLE) and emission (PL) spectra showed that the phosphors could emit red light centered at 591 nm under the 392 nm excitation, which is in good agreement with the emission wavelength from near-ultraviolet (n-UV) LED chip (370–410 nm). The results of PLE and PL indicated that the co-doped Tb3+ and Bi3+could enhance emission of Eu3+ and the fluorescent intensities of the phosphors excited at 392 nm could reach to a maximum value when the doping molar concentration of Tb3+ and Bi3+ is about 2.0% and 2.0%, respectively. The co-doping Tb3+ and Bi3+ ions can strengthen the absorption of near UV region. They can also be efficient to sensitize the emission of Eu3+, indicating that the energy transfer occurs from Tb3+ and Bi3+ to Eu3+ ions. From further investigation it can be found that co-doping Tb3+ and Bi3+ ions can also induce excitation energy reassignment between 5D0–7F1 and 5D0–7F2 in these phosphors, and result in more energy assignment to 5D0–7F2 emission in LaPO4:Eu3+, Tb3+, Bi3+. Our research results displayed that La0.94PO4:Eu3+0.02, Tb3+0.02, Bi3+0.02 could be a new one and could provide a potential red-emitting phosphor for UV-based white LED. 相似文献
17.
《Ceramics International》2017,43(12):8824-8830
A series of Eu2+ and Mn2+ co-doping Sr3GdLi(PO4)3F phosphors have been synthesized through high temperature solid state reaction. Eu2+ single doped Sr3GdLi(PO4)3F phosphors have an efficient excitation in the range of 230–430 nm, which is in good agreement with the commercial near-ultraviolet (n-UV) LED chips, and gives intense blue emission centering at 445 nm. The critical distance of the Eu2+ ions in Sr3GdLi(PO4)3F is computed and demonstrated that the concentration quenching mechanism of Eu2+ is mostly caused by the dipole-dipole interaction. By co-doping Eu2+ and Mn2+ ions in the Sr3GdLi(PO4)3F host, the energy transfer from Eu2+ to Mn2+ that can be discovered. With the increase of Mn2+ content, emission color can be adjusted from blue to white under excitation of 380 nm, corresponding to chromatic coordinates change from (0.189, 0.108) to (0.319, 0.277). The energy transfer from Eu2+ to Mn2+ ions is proven to be a dipole-dipole mechanism on the basis of the experimental results and analysis of photoluminescence spectra and decay curves. This study infers that the obtained Sr3GdLi(PO4)3F:Eu2+, Mn2+ phosphors may be a potential candidate for n-UV LEDs. 相似文献
18.
《Ceramics International》2015,41(6):7766-7772
A series of (1−x)YVO4/xY2O3:Eu3+0.006,Bi3+0.006 (0≤x≤0.54) composite phosphors was synthesized in one step by high temperature solid state reaction and the photoluminescence properties were investigated. By means of co-doping Eu3+ and Bi3+ ions into the composite matrices composed of YVO4 and Y2O3 crystals, the YVO4/Y2O3:Eu3+,Bi3+ phosphor exhibits simultaneously the blue (418 nm), green (540 nm) and orange-red (595, 620 nm) emissions. The broad blue and green emissions are attributed to the 3P1–1S0 transitions of Bi3+ ion both in Y2O3 and in YVO4 matrices. Moreover, the sharp orange-red emissions are attributed to the 5D0–7F1,2 transitions of Eu3+ ion in YVO4 matrix. By tuning the mole ratio of YVO4/Y2O3 matrices the white light-emitting could be obtained. The results indicated that when the mole ratio of Y2O3 (x) is at 0.11–0.54 mol, the (1−x)YVO4/xY2O3:Eu3+0.006,Bi3+0.006 phosphors emit white light by combining the blue, green and orange-red emissions under the excitation of 360–370 nm wavelength which matches the emission of the commercial UV-LED diode. This implies that the phosphors may be the promising white light materials with broad absorption band for white light-emitting diodes. 相似文献
19.
《Ceramics International》2016,42(16):18324-18332
A series of Eu2+-activated novel phosphor-silicate apatite Sr3LaNa(PO4)2SiO4 phosphors were synthesized by solid-state reaction. The X-ray diffraction (XRD) and Rietveld refinement, diffuse reflectance spectra, luminescent spectra, decay curves and thermal quenching properties were applied to characterize the obtained phosphors. The XRD result revealed that all the samples possessed only a single phase with hexagonal structure and the doping of Eu2+ ions were successfully incorporated into the crystal lattice. The reflectance spectra showed an obvious red-shift of the wavelength from 400 to 700 nm with increasing Eu2+ ion concentration. The three different crystallographic sites of Eu2+ ions had been confirmed by their lifetimes. All the samples exhibited broad absorption bands from 200 to 450 nm, revealing the phosphor-silicate phosphor interesting for application in the near-UV used phosphor-converted LED chips. These results suggested that the Eu2+-activated phosphor-silicate Sr3LaNa(PO4)2SiO4 phosphors have the potential for near-UV pumped white-light-emitting diodes (w-LEDs). 相似文献
20.
Jae Su Yu 《Ceramics International》2013,39(2):1029-1036
The trivalent terbium (Tb3+) ions activated CaGd4O7 (CG) phosphors were synthesized by a sol–gel method. The characterizations were performed after the samples annealed at 1500 °C. The structural and morphological properties were analyzed from the X-ray diffraction patterns and scanning electron microscope images. The photoluminescence excitation spectra showed a broad-band between the wavelengths 250 and 300 nm, which were overlapped with the Gd3+ excitation bands. The photoluminescence spectra exhibited efficient green emission due to the sensitization effect of Gd3+ ions on the Tb3+ ions when exciting with the Gd3+ wavelength at 278 nm. In order to analyze the influence of Tb3+ concentration on the luminescence behavior of Tb3+ ions in the CG host lattice, the decay curves were measured. The temperature-dependent luminescence measurements were done to identify the thermal stability of CG:Tb3+ phosphors at elevated temperatures. The cathodoluminescent spectra also showed a similar behavior to that observed in PL spectra. The CIE chromaticity coordinates as a function of Tb3+ concentration were calculated and all the obtained chromaticity coordinates have been placed in the green spectral region. 相似文献