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1.
A series of Mg2Y2Al2Si2O12:Dy3+,Eu3+ was prepared using a solid-state method, and the phosphor emitted white light by tuning the ratio of Dy3+/Eu3+. The effects of La3+/Lu3+ on the structure and luminescence properties of Mg2Y2Al2Si2O12:Dy3+,Eu3+ were explored. Under the influence of bond length and twist, the luminescence intensity of the materials increased first and then decreased under excitation with ultraviolet light. The lattice distortion of the trivalent cation La3+-substituted Mg2Y2Al2Si2O12:Dy3+ and Eu3+ phosphors was reduced, the symmetry of polyhedron occupied by the luminescence centre improved, and the thermal stability of the luminescence centre improved to a certain extent. White light emitting diodes (LEDs) were fabricated by combining a 370 nm LED chip and the Mg2Y2Al2Si2O12:Dy3+,Eu3+,La3+ (Mg2Y2Al2Si2O12:Dy3+,Eu3+,Lu3+) phosphor. The results showed that Mg2Y2Al2Si2O12:Dy3+,Eu3+,La3+/Lu3+ may have potential application in the area of white LEDs.  相似文献   

2.
In this work, we studied the luminescence properties of Tb3+‐doped MgPbAl10O17 green phosphor. To understand the excitation mechanism and corresponding emission of the prepared phosphor, its structural, morphological and photoluminescence properties were investigated. In general, for green emission, Tb3 is used as an activator and the obtained excitation and emission spectra indicated that this phosphor can be effectively excited by a wavelength of 380 nm, and exhibits bright green emission centered at 545 nm corresponding to the f → f transition of trivalent terbium ions. The chromaticity coordinates were (Cx = 0.263, Cy = 0.723). The impact of Tb3+ concentration on the relative emission intensity was investigated, and the best doping concentration was found to be 2 mol%. This study suggests that Tb3+‐doped MgPbAl10O17 phosphor is a strong candidate for a green component in phosphor‐converted white light‐emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

3.
The new borate phosphor CaB2O4:Eu3+ was synthesized by solid‐state method and their photoluminescence properties were investigated. The results show that the pure phase of CaB2O4 could be available at 900°C, CaB2O4:Eu3+ phosphor could be effectively excited by the near ultraviolet light (NUV) (392 nm), and the luminescent intensity of CaB2O4:Eu3+ phosphor reached to the highest when the doped‐Eu3+ content was 4 mol%. The emission spectra of CaB2O4:Eu3+ phosphor could exhibit red emission at 612 nm and orange emission at 588 nm, which are ascribed to the 5D07F2 and 5D07F1 transitions of Eu3+ ions. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

4.
Europium (Eu3+) and bismuth (Bi3+) co‐activated LiBaBO3 powder phosphors were synthesized by a solid‐state reaction and the structure, particle morphology, optical and photoluminescent properties were investigated. X‐Ray diffraction patterns of the LiBaBO3 phosphors crystallized in a pure monoclinic phase, i.e. there were no secondary phases due to either incidental impurities or undecomposed starting materials. Scanning electron microscopy images showed that the powders were made up of fluffy needle‐like particles that were randomly aligned. The band‐gap of the LiBaBO3 host was estimated to be 3.33 eV from the UV/vis absorption data. Blue emission was observed from the LiBaBO3 host, which is ascribed to self‐activation of the host matrix. In addition, greenish‐blue (493 nm) and red (613 nm) emissions were observed from europium‐doped samples and were attributed to the emissions of Eu2+ and Eu3+, respectively. Furthermore, after codoping with Bi3+, the emission intensity of Eu3+ located at 613 nm was significantly enhanced. From the Commission Internationale de I′Eclairage (CIE) color coordinates, white emission was observed from LiBa1–xBO3:xEu3+ (x = 0.020 and 0.025) phosphor powders with color coordinates of x = 0.368, y = 0.378 and x = 0.376, y = 0.366, respectively.  相似文献   

5.
Charge compensation is an effective way to eliminate charge defects and improve the luminescent intensity of phosphors. In this paper, a new green‐emitting phosphor ZnB2O4:Tb3+ was prepared by solid‐state reaction at 750°C. The effects of Tb3+ doping content and charge compensators (Li+, Na+ or K+) on photoluminescence properties of ZnB2O4:Tb3+ were investigated. X‐ray powder diffraction analysis confirms the sample has cubic structure of ZnB2O4. The excitation and emission spectra indicate that this phosphor can be excited by near ultraviolet light at 378 nm, and exhibits bright green emission with the highest peak at 544 nm corresponding to the 5D47F5 transition of Tb3+. The critical quenching concentration of Tb3+ in ZnB2O4 host is 8 mol%. The results of charge compensation show that the emission intensity can be improved by Na+ and K+. Specifically, K+ is the optimal one for ZnB2O4:Tb3+. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

6.
Eu2+‐activated SrMg2Al16O27 novel phosphor was synthesized by a combustion method (550°C furnace). The prepared phosphor was first characterized by X‐ray diffraction (XRD) for confirmation of phase purity. SEM analysis showed the morphology of the phosphor. The photoluminescence characteristics showed broad‐band excitation at 324 nm, which was monitored at 465 nm emission wavelength. The SrMg2Al16O27:Eu2+ phosphor shows broad blue emission centred at 465 nm, emitting a blue light corresponding to 4f65d1 → 4f7 transition. Here we report the photoluminescence characteristics of the prepared phosphor and compare it with commercial BAM:Eu2+ phosphor. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

7.
The synthesis, X‐ray diffraction, photoluminescence, TGA/DTA and FTIR techniques in Dy3+ activated Na2Sr(PO4)F phosphor are reported in this paper. The prepared phosphor gave blue, yellow and red emission in the visible region of the spectrum at 348 nm excitation. CIE color co‐ordinates of Na2Sr(PO4)F:Dy3+ are suitable as white light‐emitting phosphors. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

8.
In this article, we report the synthesis of Na2Sr1‐x(PO4)F:Eux phosphor via a combustion method. The influence of different annealing temperatures on the photoluminescence properties was investigated. The phosphor was excited at both 254 and 393 nm. Na2Sr1‐x(PO4)F:Eux3+ phosphors emit strong orange and red color at 593 and 612 nm, respectively, under both excitation wavelengths. Na2Sr1‐x(PO4)F:Eux3+ phosphors annealed at 1050°C showed stronger emission intensity compared with 600, 900 and 1200°C. Moreover, Na2Sr1‐x(PO4)F:Eux3+ phosphor was found to be more intense when compared with commercial Y2O3:Eu3+ phosphor. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

9.
We have synthesized and characterized a new BaCa2Al8O15:Eu2+,Dy3+ phosphor prepared by the combustion method. X‐ray diffraction, thermoluminescence, scanning electron microscope, time decay and optical spectral analysis photoluminescence excitation, emission spectra were used to characterize the phosphors. Broadband ultraviolet excited luminescence of the BaCa2Al8O15:Eu2+,Dy3+ was observed in the blue region (λmax = 435 nm) due to transitions from the 4f65d1 to the 4f7 configuration of the Eu2+ ion. Scanning electron microscopy has been used for exploring the morphological properties of the prepared phosphors. The BaCa2Al8O15:Eu2+ phosphor has a blue afterglow when Dy3+ ions were co‐doped. The thermoluminescence spectra show that the Dy3+ ion induces a proper trap in the phosphor with a depth of 0.67 eV and results in a long afterglow phosphorescence. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

10.
A blue‐emitting phosphor Ca12Al14O32F2:Eu2+ was synthesized using a high‐temperature solid‐state reaction under a reductive atmosphere. The X‐ray diffraction measurements indicate that a pure phase Ca12Al14O32F2:Eu2+ can be obtained for low doping concentration of Eu2+. The phosphor has a strong absorption in the range 270–420 nm with a maximum at ~340 nm and blue emission in the range 400–500 nm with chromatic coordination of (0.152, 0.045). The optimal doping concentration is ~0.24. In addition, the luminescence properties of the as‐synthesized phosphor were evaluated by comparison with those of Ca12Al14O32Cl2:Eu2+ and the commercially available phosphor BaMgAl10O17:Eu2+. The emission intensity of Ca12Al14O32F2:Eu2+ was ~72% that of BaMgAl10O17:Eu2+ under excitation at λ = 375 nm. The results indicate that Ca12Al14O32F2:Eu2+ has potential application as a near‐UV‐convertible blue phosphor for white light‐emitting diodes.  相似文献   

11.
A series of Sr2ZnWO6 phosphors co‐doped with Eu3+, Bi3+ and Li+ were prepared using the Pechini method. The samples were tested using X‐ray diffraction and luminescence spectroscopy. The results show that the samples can be effectively excited by near‐ultraviolet (UV) and UV light. The introduction of Bi3+ and Li+ significantly enhances the fluorescence emission of Sr2ZnWO6:Eu3+ and changes the light emitted by the phosphors from bluish‐green to white. When excited at 371 nm, Sr2–x–zZn1–yWO6:xEu3+,yBi3+,zLi+ (x = 0.05, y = 0.05, z = 0.05, 0.1 and 0.15) samples emit high‐performance white light. Intense red–orange emission is also observed when excited by UV light. The obtained phosphor is a potential white‐emitting phosphor that could meet the needs of excitation sources with near‐UV chips. In addition, this phosphor might have promising application as a red–orange emitting phosphor for white light‐emitting diodes based on UV light‐emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

12.
A series of Eu2+ activated SrCaP2O7 pyrophosphate phosphors were synthesized by the modified solid‐state reaction method. The X‐ray diffraction (XRD) and photoluminescence (PL) properties of these phosphors were investigated at room temperature. The excitation spectra indicate that these phosphors can be effectively excited by Hg‐free excitation. The emission spectra exhibit strong blue performance, which is due to the 4f65d1→4f7 transition of Eu2+. The Fourier transform infrared spectrum at room temperature was investigated and surface morphology has been studied by scanning electron microscope. The prepared phosphor exhibited intense blue emission at the 427 nm owing to Eu2+ ion by Hg‐free excitation at 330 nm, that is, solid‐state lighting excitation. Hence, the availability of such a phosphor will significantly help in the growth of blue‐emitting solid‐state lighting applications. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

13.
A blue CaMgSi2O6:Eu2+ phosphor was prepared by the solid‐state reaction method and the phosphor characterized in terms of crystal structure, particle size, photoluminescence (PL), thermoluminescence (TL) and mechanoluminescence (ML) properties using X‐ray diffraction (XRD), transmission electron microscopy (TEM), PL spectroscopy, TLD reader and ML impact technique. The XRD result shows that phosphor is formed in a single phase and has a monoclinic structure with the space group C2/c. Furthermore, the PL excitation spectra of Eu2+‐doped CaMgSi2O6 phosphor showed a strong band peak at 356 nm and the PL emission spectrum has a peak at 450 nm. The depths and frequency factors of trap centers were calculated using the TL glow curve by deconvolution method in which the trap depths were found to be 0.48 and 0.61 eV. The formation of CaMgSi2O6:Eu2+ phosphor was confirmed by Fourier transform infrared spectroscopy. The ML intensity increased linearly with the impact velocity of the piston used to deform the phosphor. It was shown that the local piezoelectricity‐induced electron bombardment model is responsible for the ML emission. Finally, the optical properties of CaMgSi2O6:Eu2+ phosphors are discussed. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

14.
Long persistence phosphor CaAl4O7: Eu2+, Dy3+ were prepared by a combustion method. The phosphors were characterized by means of X‐ray diffraction (XRD), scanning electron microscopy (SEM), decay time measurement techniques and photoluminescence spectra (PL). The CaAl4O7: Eu2+, Dy3+ phosphor showed a broad blue emission, peaking at 445 nm when excited at 341 nm. Such a blue emission can be attributed to the intrinsic 4f → 5d transitions of Eu2+ in the host lattices. The lifetime decay curve of the Dy3+ co‐doped CaAl4O7: Eu2+ phosphor contains a fast decay component and another slow decay one. Surface morphology also has been studied by SEM. The calculated CIE colour chromaticity coordinates was (0.227, 043). We have also discussed a possible long‐persistent mechanism of CaAl4O7:Eu2+, Dy3+ phosphor. All the results indicate that this phosphor has promising potential for practical applications in the field of long‐lasting phosphors for the purposes of sign boards and defence. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

15.
BaGd2‐xO4:xEu3+ and Ba1‐yGd1.79‐2yEu0.21Na3yO4 phosphors were synthesized at 1300°C in air by conventional solid‐state reaction method. Phosphors were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence excitation (PLE) spectra, photoluminescence (PL) spectra and thermoluminescence (TL) spectra. Optimal PL intensity for BaGd2‐xO4:xEu3+ and Ba1‐yGd1.79‐2yEu0.21Na3yO4 phosphors at 276 nm excitation were found to be x = 0.24 and y = 0.125, respectively. The PL intensity of Eu3+ emission could only be enhanced by 1.3 times with incorporation of Na+ into the BaGd2O4 host. Enhanced luminescence was attributed to the flux effect of Na+ ions. However, when BaGd2O4:Eu3+ phosphors were codoped with Na+ ions, the induced defects confirmed by TL spectra impaired the emission intensity of Eu3+ ions. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

16.
The individual emission and energy transfer between Ce3+ and Eu2+ or Dy3+ in BaCa(SO4)2 mixed alkaline earth sulfate phosphor prepared using a co‐precipitation method is described. The phosphor was characterized by X‐ray diffraction (XRD) and photoluminescence (PL) studies and doped by Ce;Eu and Dy rare earths. All phosphors showed excellent blue–orange emission on excitation with UV light. PL measurements reveal that the emission intensity of Eu2+ or Dy3+ dopants is greater than when they are co‐doped with Ce3+. An efficient Ce3+ → Eu2+ [2T2g(4f65d) → 8S7/2(4f7)] and Ce3+ → Dy3+ (4 F9/26H15/2 and 4 F9/26H13/2) energy transfer takes place in the BaCa(SO4)2 host. A strong blue emission peak was observed at 462 nm for Eu2+ ions and an orange emission peak at 574 nm for Dy3+ ions. Hence, this phosphor may be used as a lamp phosphor. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

17.
The antimonate compound La3SbO7 has high chemical stability, lattice stiffness and thermal stability. Orange–red‐emitting antimonate‐based phosphors La3SbO7:xSm3+ (x = 0.02, 0.05, 0.08, 0.10, 0.15, 0.20 and 0.25) were synthesized. The phase structure and photoluminescence properties of these phosphors were investigated. The emission spectrum obtained on excitation at 407 nm contained exclusively the characteristic emissions of Sm3+ at 568, 608, 654 and 716 nm, which correspond to the transitions from 4G5/2 to 6H5/2, 6H7/2, 6H9/2 and 6H11/2 of Sm3+, respectively. The strongest emission was located at 608 nm due to the 4G5/26H7/2 transition of Sm3+, generating bright orange–red light. The critical quenching concentration of Sm3+ in La3SbO7:Sm3+ phosphor was determined as 10% and the energy transfer between Sm3+ was found to be through an exchange interaction. The International Commission on Illumination chromaticity coordinates of the La3SbO7:0.10Sm3+ phosphors are located in the orange–red region. The La3SbO7:Sm3+ phosphors may be potentially used as red phosphors for white light‐emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

18.
An intense green luminescent Na2Ca(PO4)F:Mn2+ phosphor has been prepared at high temperature by reduction treatment in a charcoal environment. The emission band of Mn2+ was obtained at around 522 nm (green) under 259 nm excitation. Enhancement in emission intensity arising from the thermal treatment is reported. The intense emission of the spectrum was assigned to electronic transitions 4T16A1 of Mn2+ ions. Intense PL emission suggested that temperature employed plays an important role in the present matrix. X‐ray diffraction pattern, photoluminescence and morphology by SEM of the host lattice of phosphors at different temperatures have been reported in this paper. The results obtained show that the present phosphor has potential for application in green emitting phosphors for the lamp industry. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

19.
K. N. Shinde  K. Park 《Luminescence》2013,28(5):793-796
A series of efficient Li3Al2(PO4)3:Eu2+ novel phosphors were synthesized by the facile combustion method. The effects of dopant on the luminescence behavior of Li3Al2(PO4)3 phosphor were also investigated. The phosphors were characterized by X‐ray diffraction, field emission scanning electron microscope and photoluminescence techniques. The result shows that all samples can be excited efficiently by near‐ultraviolet excitation under 310 nm. The emission was observed for Li3Al2(PO4)3:Eu2+ phosphor at 425 nm, which corresponded to the d → f transition. The concentration quenching of Eu2+ was observed in Li3Al2(PO4)3:Eu2+ when the Eu concentration was at 0.5 mol%. The prepared powders exhibited intense blue emission at the 425 nm owing to the Eu2+ ion by Hg‐free excitation at 310 nm (i.e., solid‐state lighting excitation). Consequently, the availability of such a phosphor will significantly help in the development of blue‐emitting solid‐state lighting applications. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

20.
Di‐barium magnesium silicate phosphor doped with Eu2+ and Dy3+ was prepared using a solid‐state reaction technique under a reducing atmosphere. The sample underwent impulsive deformation by impact from a piston for mechanoluminescence (ML) investigations. The temporal ML characteristics of the phosphor were observed, which expressed a single sharp peak with a long decaying period. To investigate the luminescence centre responsible for the ML peak, the ML spectrum of the phosphor was also observed. The recorded ML spectrum was similar in shape and peak wavelength to the photoluminescence (PL) spectrum, which verifies the existence of a single emission centre due to the transition of Eu2+ ions, i.e. transitions from any of the sublevels of the 4f65d1 configuration to the 8S7/2 level of the 4f7 configuration. Decay rates for different impact velocities were also calculated using curve‐fitting techniques. The time of the ML peak and the rate of decay did not change significantly with respect to increasing impact velocity of the load and peak ML intensity varied linearly. The mechanism of the ML emission was also discussed. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

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