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1.
《Ceramics International》2023,49(13):21872-21882
The near-infrared (NIR) luminescence in S+E+O bands of tellurite glasses doped with Nd3+/Tm3+ and Ag nanoparticles (NPs) was investigated. The tellurite glasses were prepared by melt-quenching and heat-treated techniques. Under the excitation of 808 nm laser, Nd3+/Tm3+ doped tellurite glasses produced three NIR luminescence bands of 1.33, 1.47 and 1.85 μm, originating from Nd3+:4F3/24I13/2, Tm3+:3H43F4 and Tm3+:3F43H6 transitions respectively. Interestingly, a broadband luminescence spectrum ranging from 1280 to 1550 nm with the FWHM (full width at half maximum) about 201 nm was obtained due to the overlapping of the first two NIR bands. Further, the peak intensity of this broadband luminescence was increased by 75% after the introduction of Ag NPs with diameter in 10–20 nm. The analysis of fluorescence decay shows that compared with the enhanced local electric field, the energy transfer from Ag species to Nd3+ and Tm3+ ions plays a major role in luminescence enhancement. The findings in this work indicate that tellurite glass co-doped with Nd3+/Tm3+ and Ag NPs is a potential gain material applied in the S+E+O-band photonic devices.  相似文献   

2.
AgNO3/EuF3/YbF3 tri‐doped oxyfluoride glass was prepared by a melt‐quenching method, in which a high‐efficient broadband spectral modification can be realized due to the simultaneous energy‐transfer processes of Eu3+→Yb3+, molecular‐like Ag (ML‐Ag) clusters→Yb3+, and ML‐Ag clusters→Eu3+→Yb3+. The spectral measurements indicated that besides the F‐center brought by the fluorides, the formation of the ML‐Ag clusters and the evolution of silver species within the glass matrix were also closely related to the introduction of Eu3+ and Yb3+ ions and which in return greatly affected the luminescence properties of these rare‐earth ions. As the UV‐visible irradiation in the wavelength region of 250–600 nm can be efficiently converted into near‐infrared emission around 1000 nm in the AgNO3/EuF3/YbF3 tri‐doped glass, which thus has promising application in enhancing the photovoltaic conversion efficiency of the silicon solar cell.  相似文献   

3.
Due to the widely tunable band gap and broadband excitation, CdS quantum dots (QDs) show great promise for yellow-light luminescence center in white-light-emitting devices. The light intensity of the CdS QD-doped glass was enhanced by doping the Tm3+ ions due to the higher absorption rate. The influence of Tm3+ ions on the surface structure of CdS QDs was enormous according to the first-principles calculations. Doping Tm3+ ions change the surface state of CdS QDs, which will fix the QDs emission peaks and enhance the luminescence of CdS QDs at a lower heat-treatment temperature. White-light emission was obtained by tuning the relative concentration between Tm3+/CdS QDs. However, there is a fundamental challenge to fabricate QD-doped glass fibers by rod-in-tube method since uncontrollable QDs crystallization is hard to avoid. Herein, a white-light-emitting borosilicate glass fiber was fabricated by the “melt-in-tube” method using a special designed Tm3+/CdS QDs co-doped borosilicate glass with low-melting temperature as fiber core. After heat treatment, ideal white-light emission was observed from the fiber under excitation at single wavelength (359 nm). This finding indicates that Tm3+/CdS QDs co-doped glass fiber with white-light-emitting devices has potential application as gain medium of white-light-emitting sources and fiber lasers.  相似文献   

4.
Novel LaMgAl11O19:Tm3+, Dy3+ phosphors were prepared utilizing a high‐temperature solid‐state reaction method. The phase formation, luminescence properties, energy‐transfer mechanism from the Tm3+ to the Dy3+ ions, the thermal stability, and CIE coordinates were investigated. When excited at 359 nm, the LaMgAl11O19: xTm3+ phosphors exhibit strong blue emission bands at 455 nm. After codoping with Dy3+ and excitation at 359 nm, the LaMgAl11O19:0.03Tm3+, yDy3+ phosphors emitted white light consisting of the characteristic emission peaks of Tm3+ and Dy3+. The Dy3+ emission intensity increased with the Dy3+ concentration due to the energy transfer from Tm3+ to Dy3+, and concentration quenching due to the high Dy3+ doping concentration (= 0.1 mol) did not occur. The calculation of the CIE coordinates of the LaMgAl11O19:Tm3+, yDy3+ phosphors revealed the tunability of the emission color from blue to bluish‐white and to white by changing the excitation wavelength and the doping concentration. An energy transfer from Tm3+ to Dy3+ by dipole–dipole interaction was confirmed by the decay curve, lifetime, and energy‐transfer efficiency measurements. When excited at 359 nm, the LaMgAl11O19:Tm3+, Dy3+ phosphor also showed good thermal stability, suggesting that it can be used in white LEDs excited by a GaN‐based ultraviolet LED.  相似文献   

5.
Rare‐earth‐doped oxyfluoride germanate and borate glasses were synthesized and next studied using spectroscopic methods. Influence of fluoride modifier on luminescence properties of rare earths in different glass hosts was examined. The excitation and emission spectra of Pr3+ and Er3+ ions in the studied glasses were registered. The emission spectra of Pr3+ ions in germanate and borate glasses are quite different and depend strongly on the glass host. In samples doped with Er3+ ions emission bands located around 1530 nm corresponding to the main 4I13/24I15/2 laser transition were registered, independently of the glass host. Quite long‐lived near‐infrared luminescence of Er3+ ions was observed for germanate glasses with low BaF2 content, while in borate glass systems influence of barium fluoride on luminescence lifetimes is not so evident. The Judd–Ofelt calculations were used in order to determine quantum efficiencies of excited states of rare‐earth ions in germanate and borate glasses.  相似文献   

6.
Using a modified sol–gel method, LiLa(MoO4)2: Tm3+/Ho3+/Yb3+ phosphors with tailorable up‐conversion (UC) emission colors were prepared. Under the excitation of a 980 nm laser diode, up‐conversion red and green emissions in Ho3+/Yb3+ co‐doped and blue emission in Tm3+/Yb3+ co‐doped LiLa(MoO4)2 were observed, respectively. The intensities of the RGB (red, green, and blue) emissions could be controlled by varying concentrations of Tm3+ or Ho3+, and the optimal composition was also determined. In Tm3+/Ho3+/Yb3+ co‐doped LiLa(MoO4)2, the UC emission colors could be tuned from blue through white to yellow by adjusting the concentrations of Tm3+ or Ho3+. The UC excitation mechanisms were also investigated based on the power dependence of UC luminescence intensity.  相似文献   

7.
《Ceramics International》2020,46(17):27199-27204
NaY(WO4)2 is one of the excellent host materials for high-efficient upconversion luminescence, but it is still challenging to obtain red emission via lanthanide doping. In this work, pure red emission was achieved in the heavily-Er3+-doped NaY(WO4)2 by using a 1550 nm laser diode and introducing mediator Tm3+ ions in the lattice. On basis of the analysis of steady-state and transient-state luminescence properties related to dopant concentration and excitation wavelength, all possible red emission mechanisms were discussed. Finally, it has been demonstrated that the high-purity red emission was due to the several energy transfer processes between Er3+ and Tm3+. Our results provide a convenient pathway to investigate the upconversion luminescence mechanisms.  相似文献   

8.
Ion exchange between H+ and Eu3+ and/or Tb3+ was studied in the material modified by in situ sorption and thermal polymerization of acrylic acid in low‐density polyethylene (LDPE–PAA) and in the composite system LDPE–Fe2O3–PAA. Fluorescence spectroscopy showed evidence of Eu3+ and/or Tb3+ ion exchanges in these materials. The matrix LDPE–PAA after Eu(III) ion exchange presented luminescence (excitation 265 nm). This was explained by an energy‐transfer process from the matrix LDPE–PAA to Eu3+ ions. The LDPE–PAA matrix after simultaneous Eu3+/Tb3+ ion exchange exhibited Eu3+ and Tb3+ ion luminescence (excitation 265 nm), confirming an energy‐transfer process from LDPE–PAA to Eu3+ ions in LDPE–PAA–Eu3+–Tb3+ matrix. Fe2O3 in LDPE–Fe2O3–PAA quenched the matrix for excitation at 265 nm and no emission at the region 400 nm was observed. The luminescence of Tb3+ ions in the matrix LDPE–Fe2O3–PAA–Tb3+ (excitation 265 nm) was partially quenched by Fe2O3. However, a weak emission of Eu3+ ions was observed (excitation 265 nm) in the matrix LDPE–Fe2O3–PAA after simultaneous Eu3+ and Tb3+ ion exchanges, suggesting an energy transfer from Tb3+ to Eu3+ ions. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 919–931, 2000  相似文献   

9.
Rare‐earth vanadates of the form REVO4 (RE = Y, La, Gd, and Lu) doped by Yb3+/Ho3+, Yb3+/Er3+, or Yb3+/Tm3+ lanthanide ions were successfully synthesized using the sol–gel method and annealing at 600°C in an air atmosphere. The structure and morphology of the prepared nanocrystals were investigated by X‐ray diffraction, thermogravimetric analysis, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. All prepared materials were homogenous and had nanosized dimensions. Their elemental compositions were confirmed by optical emission spectrometry. Spectroscopic analysis of the materials was carried out by measuring excitation and emission spectra, luminescence decays, and dependence between the intensity of the luminescence and the laser energy. Following effective excitation by NIR radiation, Ln3+ co‐doped vanadate matrices exhibited a strong up‐conversion (UC) luminescence. Differences in spectroscopic properties between monoclinic LaVO4 and tetragonal YVO4, GdVO4, or LuVO4 doped by Ln3+ ions were observed, indicating the influence of the crystal structure on the UC emission. Drawing conclusions from these spectroscopic investigations, the UC mechanisms were proposed, including energy‐transfer processes between Yb3+ ions and emitting ions.  相似文献   

10.
Eu‐doped transparent oxyfluoride aluminosilicate glass was prepared by controlling with Al codoping of melt‐quenched glass fabricated under air atmosphere. In the presence of Al input, the photoluminescence emission spectra under 393 nm excitation shows a blue shift by adjusting the ratio of Eu3+ and Eu2+. After heat treatment of glass, the ratio of Eu3+ and Eu2+ of luminescence emission were changed by controlling treatment temperature. The PL intensity of Eu3+ and Eu2+ ions in the glass‐ceramics (GC) was much stronger than in the precursor glass (PG). The possible mechanism responsible for color tuneability of the ratio of Eu3+ and Eu2+ doped was discussed.  相似文献   

11.
A series of Ce3+/Dy3+‐doped oxyfluoride borosilicate glasses prepared by melt‐quenching method are investigated for light‐emitting diodes applications. These glasses are studied via X‐ray diffraction (XRD), optical absorption, photoluminescence (PL), color coordinate, and Fourier transform infrared (FT‐IR) spectra. We find that the absorption and emission bands of Ce3+ ions move to the longer wavelengths with increasing Ce3+ concentrations and decreasing B2O3 and Al2O3 contents in the glass compositions. We also discover the emission behavior of Ce3+ ions is dependent on the excitation wavelengths. The glass structure variations with changing glass compositions are examined using the FT‐IR spectra. The influence of glass network structure on the luminescence of Ce3+/Dy3+ codoped glasses is studied. Furthermore, the near‐ideal white light emission (color coordinate x = 0.32, y = 0.32) from the Ce3+/Dy3+ codoped glasses excited at 350 nm UV light is realized.  相似文献   

12.
Intense visible and near‐infrared frequency upconversion and a frequency downconversion photoluminescence have been reported for the first time in Tm3+ and Er3+ co‐doped transparent α‐Sialon ceramics under 980 nm excitation. The α‐Sialon ceramics were prepared by hot‐press sintering technique. Intense upconversion bands at 554, 678, 803 nm, and a downconversion band at 1530 nm were observed as a result of the efficient energy transfer between Er3+ and Tm3+ ions. The quadratic dependence of upconversion intensities on the excitation power indicates that the upconversion process is governed by two‐photon absorption process. The sintered samples of thickness 0.20 mm have transparency above 80% in the range of 2000 to 4200 nm and it reaches as high as 82% at 3350 nm. Moderately low phonon energy was found with the highest frequency band at 828 cm?1. These novel properties manifest the potential applications of transparent α‐Sialon ceramics as a multifunctional material.  相似文献   

13.
Mid-infrared (MIR) fiber lasers have wide application prospects and great commercial value in the fields of medical operation, remote sensing and military weapon, etc. At present, Tm3+-doped glass can obtain broadband luminescence at 2 μm, the introduction of Ho3+ or Er3+ ions also shows a tunable MIR emission but with limited success. Herein, the rare-earth (RE) doped glass with quantum dots (QDs) precipitation is proposed for achieving ultra-broadband MIR emissions. The types and sizes of QDs are determined by the XRD and TEM, and their optical properties are further characterized by the absorption and emission spectra as well as the lifetime decay curves. It is found that the diameter of the QDs is gradually increased from 1.7 to 5.1 nm by increasing the heat-treated temperature from 490°C to 530°C, respectively. Interestingly, an ultra-broadband emission covering 1400-2600 nm is achieved from the heat-treated glass upon the excitation of 808 nm laser diode as a result of an overlapped emission from Tm3+ and PbS. All results suggest that these QDs-precipitated RE-doped glasses have important application prospects in ultra-broadband MIR laser glass, glass fiber, and fiber lasers.  相似文献   

14.
The influence of the addition of 1 mol% Tm2O3 on the nanocrystallization of LaF3 in a glass of composition 55SiO2–20Al2O3–15Na2O–10LaF3 (mol%) has been studied. Tm2O3 affects the phase separation in the glass and delays the onset of crystallization with respect to the undoped glass. Additionally, the maximum LaF3 crystal size is slightly greater than that in the undoped glass–ceramics. The microstructural and compositional changes in the glass matrix have been studied using several techniques, including viscosity, dilatometry, X‐ray and neutron diffraction (XRD, ND), quantitative Rietveld refinement, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and Raman spectroscopy. Photoluminescence measurements indicate that the Tm3+ ions are distributed between the glassy matrix and LaF3 crystals. Eu2O3 has been used as structure probe and part of the Eu3+ ions are reduced to Eu2+ when incorporated in the LaF3 nano‐crystals. Up‐conversion spectra under IR‐excitation show a higher intensity of the blue emission in the Tm‐doped glass–ceramic compared with that in the glass.  相似文献   

15.
Transparent glass‐ceramics containing Ce3+: Y3Al5O12 phosphors and Eu3+ ions were successfully fabricated by a low‐temperature co‐sintering technique to explore their potential application in white light‐emitting diodes (WLEDs). Microstructure of the sample was studied using a scanning electron microscope equipped with an energy dispersive X‐ray spectroscopy. The impact of co‐sintering temperature, Ce3+: Y3Al5O12 crystal content and Eu3+ doping content on optical properties of glass‐ceramics were systematically studied by emission, excitation spectra, and decay curves. Notably, the spatial separation of these two different activators in the present glass‐ceramics, where Ce3+ ions located in YAG crystalline phase while the Eu3+ ones stayed in glass matrix, is advantageous to the realization of both intense yellow emission assigned to Ce3+: 5d→4f transition and red luminescence originating from Eu3+: 4f→4f transitions. As a result, the quantum yield of the glass‐ceramic reached as high as 93%, and the constructed WLEDs exhibited an optimal luminous efficacy of 122 lm/W, correlated color temperature of 6532 K and color rendering index of 75.  相似文献   

16.
In the paper, the upconversion luminescence of 70GeO2–30[Ga2O3–BaO–Na2O] glass system co-doped with Yb3+/Tm3+ ions was investigated. Strong blue emission at 478 nm corresponding to the transition 1G4 → 3H6 in thulium ions was measured under the excitation of 976-nm diode laser. The dependence of the upconversion emission upon the thulium ion concentration was studied to determine the optimal conditions of energy transfer between energy levels of active dopants. The most effective energy transfer Yb3+ → Tm3+ was obtained in glass co-doped with molar ratio of dopant 0.7 Yb2O3/0.07 Tm2O3. The increase in thulium concentration more than 0.07 mol% results in the reverse energy transfer from Tm3+ → Yb3+, which leads to rapid quenching of the luminescence line at the wavelength 478 nm. In germanate glass co-doped with 0.7Yb2O3/0.07Tm2O3, the longest lifetime of 1G4 level equal 278 μs was achieved. The presented results indicate that elaborated germanate glass co-doped with Yb3+/Tm3+ ions is a promising material that can be used to produce fiber lasers and superluminescent fiber sources generating radiation in the visible spectrum.  相似文献   

17.
Dy3+–Tm3+ ions codoped SrMg2La2W2O12 (strontium magnesium lanthanum tungstate) phosphors were synthesized by conventional high‐temperature solid‐state reaction method. X‐ray analysis of the end products revealed the well‐crystallized phases with orthorhombic structure. The functional groups present in the phosphors were studied by the Fourier transform infrared measurements. To know the potential applicability of these phosphors for white light emission, the excitation and emission spectra were recorded. The excitation spectra exhibited an intense broad band at 313 nm, pertaining to the O → W ligand‐to‐metal charge‐transfer state (LMCT) of the host. With the excitation of LMCT band (313 nm), the decay curves of singly doped SrMg2La2W2O12:Dy phosphors exhibited single exponential, where as the codoped SrMg2La2W2O12:DyTm phosphors exhibited double exponential nature. The luminescence colors of these phosphors were estimated from Commission Internationale de L'Eclairage (CIE) coordinates using the photoluminescence data. The color of singly doped SrMg2La2W2O12:Dy phosphor has been tuned by codoping with Tm3+ ions. It has been noticed that the CIE chromaticity coordinates (x,y) determined from the luminescence spectrum of singly Dy3+ doped SrMg2La2W2O12 phosphor shifted toward the white light region, when codoped with Tm3+ ions. The increase in correlated color temperatures (Tcct) has been noticed with the increase of Tm3+ ions concentration in SrMg2La2W2O12:DyTm phosphors.  相似文献   

18.
Spectroscopic properties of Ba2Gd(BO3)2Cl: Dy3+ and Ba2Gd(BO3)2Cl: Dy3+, Tm3+ under vacuum ultraviolet (VUV) and ultraviolet (UV) light excitations were investigated. Dy3+ single‐doped Ba2Gd(BO3)2Cl showed broad absorption band in the VUV region, and bright warm white light with chromaticity coordinates (CIE) of (0.340, 0.381) upon VUV excitation at 172 nm, demonstrating this phosphor's applicability in mercury free lamps. Upon direct excitation Tm3+ from its 6F6 level to 1D2 level, the decrease of emission intensity and lifetime of Tm3+ 1D23F4 emission with increasing concentration of Dy3+ in Ba2Gd(BO3)2Cl: Dy3+, Tm3+ confirmed the occurrence of energy transfer from Tm3+ to Dy3+. In addition, Ba2Gd(BO3)2Cl: Dy3+, Tm3+ could be efficiently excited by 358 nm UV light and its emission color could be tuned from blue to yellow by codoping Tm3+. When 1% Tm3+ and 5% Dy3+ were codoped in the Ba2Gd(BO3)2Cl, intensive white‐emitting light with CIE of (0.352, 0.328) and correlated color temperature of 4589 K was achieved upon 358 nm excitation, revealing the potential application of Ba2Gd(BO3)2Cl: Dy3+, Tm3+ for white light‐emitting diodes (LEDs).  相似文献   

19.
A growing demand for white light-emitting diodes (W-LEDs) gives rise to continuous exploration of functional fluorescence glasses. In this paper, Tm3+/Dy3+ single- and co-doped glasses with composition (in mol%) of 30P2O5–10B2O3–23SrO–37K2O were synthesized using the melt-quenching method in air. The physical properties, glass structure, luminescence characteristics and energy transfer mechanism of the glasses were systematically studied. As glass network modifiers, Tm3+ and Dy3+ ions can densify the glass structure. Excitation wavelength and doping concentration of Tm3+/Dy3+ ions have a direct impact on the emission intensities of blue and orange light as well as the color coordinate of the as-prepared glasses. A white light very close to standard white light can be obtained under 354 nm excitation when the content of Tm3+ and Dy3+ is 0.2 mol% and 1.0 mol%, respectively. The results of the emission spectra and decay curves reveal the existence of energy transfer from Tm3+ to Dy3+. The analytic results based on the Inokuti-Hirayama model indicate that the electrical dipole-dipole interaction may be the main mechanism of energy transfer. Moreover, Tm3+/Dy3+ co-activated glass phosphor has good thermal stability and chrominance stability and it is a promising candidate for white LEDs and display device.  相似文献   

20.
The three‐dimensional ordered macroporous (3DOM) LaPO4:Eu3+ films and Ag nanoparticles (NPs) were prepared via a template‐assisted process and sodium citrate reduction method, respectively. Composite systems consisting of 3DOM LaPO4:Eu3+ films and Ag NPs were obtained by adding the Ag NPs into voids of 3DOM LaPO4:Eu3+ films. The influence of Ag NPs on photoluminescence of 3DOM LaPO4:Eu3+ was investigated. The results show that photoluminescence properties of 3DOM LaPO4:Eu3+ films were enhanced after addition of Ag NPs, which was attributed to the local surface plasmons resonance effect of Ag NPs.  相似文献   

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