This paper reports the preparation of yttrium oxide(Y_(2)O_(3))doped with various concentrations of Er^(3+)using high temperature synthesis method.Photoluminescence(PL)emission spectra of the samples were recorded at ...This paper reports the preparation of yttrium oxide(Y_(2)O_(3))doped with various concentrations of Er^(3+)using high temperature synthesis method.Photoluminescence(PL)emission spectra of the samples were recorded at an excitation of 980 nm laser source.Two prominent peaks centered at 484 nm and 574 nm were found and attributed to the^(2)P3/2→^(4)I_(11/2)and^(4)S_(3/2)→^(4)I_(15/2),respectively.The sample with 2.5 mol%of Er^(3+)provided the optimum intensity in emission spectra.The sample with optimum PL emission was investigated for its thermoluminescence(TL)glow curve exhibited the second order kinetics.The peak TL intensity was found around 236°C,i.e.,towards high temperature which supports the fact of formation of deeper traps.Therefore,the material taken may be regarded as a good candidate for light emitting diode(LED)applications.展开更多
Cr^(3+)-activated phosphors have attracted significant attention for their tunable emission,spanning narrow-band red to broadband near-infrared(NIR)luminescence,depending on the crystal field environment.Here,we repor...Cr^(3+)-activated phosphors have attracted significant attention for their tunable emission,spanning narrow-band red to broadband near-infrared(NIR)luminescence,depending on the crystal field environment.Here,we report the realization of wideband NIR emission in Cr^(3+)-doped GaScO_(3)(GaScO_(3):Cr^(3+))phosphors with perovskite structure.The phosphors were synthesized by traditional solid-state reaction method.The first-principles calculations were conducted and the results demonstrate that the octahedral[GaO_(6)]sites exhibit relatively weak crystal field strength(Dq/B≈2.2),facilitating efficient spin-allowed transitions of Cr^(3+)from the^(4)T_(2)state to the^(4)A_(2)state.The photoluminescence spectroscopy revealed an exceptionally broad NIR emission band from a range of 700 nm-1200 nm with full width at half maximum(FWHM)of 145 nm under 465-nm excitation.Overall,these results highlight the viability of GaScO_(3):Cr^(3+)as a highly promising material for wideband NIR applications.展开更多
To meet the high demands of modern technology for temperature sensors,Lu_(2)WO_(6):Sm^(3+)self-activated phosphors were selected to design four-mode optical thermometers.A comprehensive investigation was conducted on ...To meet the high demands of modern technology for temperature sensors,Lu_(2)WO_(6):Sm^(3+)self-activated phosphors were selected to design four-mode optical thermometers.A comprehensive investigation was conducted on the synthetic method,structural and luminescent characteristics,and energy transfer mechanism([WO6]6-→Sm^(3+)). Due to the different temperature responses of two emission centers([WO6]6-and Sm^(3+)),the temperature sensing capability of Lu_(2)WO_(6):Sm^(3+)phosphors was studied.Fluorescence intensity(FI),fluorescence intensity ratio(FIR),Commission Internationale de L'Eclairage coordinates and excitation intensity ratio are the four modes for temperature sensing,and their maximum relative sensitivities are 2.62%/K(350 K),2.06%/K(320 K),0.67%/K(329 K) and 2.42%/K(303 K),respectively.Furthermore,within 303-483 K temperature range,the relative sensitivities based on FI and FIR are bigger than 1.67%/K and 1.16%/K,respectively.Our findings suggest that Lu_(2)WO_(6):Sm^(3+)phosphors with four temperature measurement modes might be applied in multi-mode self-calibration optical thermometers.展开更多
Cr^(3+)-activated spinel-type phosphors have great potential in different application scenes due to their unique sharp and far-red(FR)emission.However,the multi-functionalization of these phosphors is still limited by...Cr^(3+)-activated spinel-type phosphors have great potential in different application scenes due to their unique sharp and far-red(FR)emission.However,the multi-functionalization of these phosphors is still limited by their unsatisfied comprehensive properties.Herein,a simple composition engineering was used to explore versatile phosphors,using Ga^(3+)to substitute Al^(3+)to improve the optical performances of spinel LiAl5-xGa_(x)O_(8):Cr^(3+).The substitution of Ga^(3+)evidently affects the crystal field environment of Cr^(3+)and further accounts for the luminescence optimization.Using the optimized phosphor,two sensitive thermometers based on fluorescence intensity ratio(FIR)technique were explored on account of the different temperature dependencies of^(4)T_(2)→^(4)A_(2)and2E→^(4)A_(2)emission and of R2and R1emission.The maximum relative sensitivity Sr are 1.29%/K at 323 K and 1.94%/K at 298 K,respectively,which are superior to that of the Ga^(3+)-unsubstituted one.Besides,the Ga^(3+)→Al^(3+)substitutions endow the resultant phosphors with larger atomic number(Zeff)and theoretical density,which is more conducive to improving X-ray-stimulated emission for X-ray detection.Finally,the potential applications of the developed phosphor are also reflected in plant growth and night vision surveillance,as it is shown to be capable of matching with the absorption of phytochrome PFRand visualizing objects in the dark.This contribution not only proves that the developed LiAl5-xGa_(x)O_(8):Cr^(3+)FR phosphors are promising versatile platforms,but also provides an essential guidance for designing more novel multi-functional materials.展开更多
Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity re...Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity remain rare.Herein,NaLnTe_(2)O_(7):Eu^(3+)(Ln=Y and Gd)phosphors were synthesized using a rapid microwave-assisted solidstate(MASS)method to fulfill these applications.Under 395 nm excitation,NaLnTe_(2)O_(7):Eu^(3+)exhibit the characteristic ^(5)D_(0)→^(7)F_(J)(J=1–4)transitions of Eu^(3+).Substituting Gd^(3+) for Y^(3+) enhances the luminescence by approximately 2.42 times.Structural analyses reveal that the improved luminescent properties are attributed to the more distorted and appropriate coordination environment in NaGdTe_(2)O_(7):Eu^(3+).Finally,white-LEDs using NaGdTe_(2)O_(7):Eu^(3+)as the red-component produce white light with high Ra of 89.Furthermore,the distinct thermal responses of the ^(5)D_(0)→^(7)F_(J) transitions enable NaLnTe_(2)O_(7):Eu^(3+)to function as temperature sensors via fluorescence intensity ratio(FIR)strategy.NaYTe_(2)O_(7):Eu^(3+)possesses the maximum relative/absolute sensitivity of 1.45%/15.93%K^(-1),whereas NaGdTe_(2)O_(7):Eu^(3+)achieves the maximum relative/absolute sensitivity of 1.53%/30.24% K^(-1).This work highlights the significance of cationic substitution in enhancing luminescent properties for multifunctional applications.展开更多
Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material ...Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material was successfully synthesized and Er^(3+)ions were successfully doped into the main lattice.This doping does change the basic structure of the crystal.BaLaGaO_(4):Er^(3+)phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light.The optimal doping concentration is found to be x=0.04.To quantify the temperature sensitivity of the phosphor,the fluorescence intensity ratio method was used.Within the temperature range of 298-473 K,the maximum relative sensitivities are 1.35%/K(298 K,381 nm)and 1.45%/K(298 K,980 nm),respectively.The maximum absolute sensitivities are 0.67%/K(473 K,381 nm)and 0.69%/K(473 K,980 nm),respectively.Finally,white light-emitting diodes(WLEDs)with a high colour index of Ra=82and a relatively low correlated colour temperature of CCT=5064 K are obtained by integrating the synthesized BaLaGaO_(4):0.04Er^(3+)green phosphor into warm WLEDs devices.These results suggest that Er^(3+)-activated BaLaGaO_(4)multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.展开更多
To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through...To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through solid reaction process.The crystal structure,up-conversion luminescence,energy transfer,thermal stability and optical temperature sensing performances were studied in detail.Under 980 nm laser excitation,the KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor exhibits distinctive emission bands of Ho^(3+)at545,660,and 755 nm,and excellent illuminant performance.Based on the thermally coupled levels(TCLs)of Ho^(3+),both the relative sensitivity(S_(r))and absolute sensitivity(S_(a))display similar change trends,with the highest values of 6.73%/K(@298 K)and 5.69%/K(@298 K),respectively.Furthermore,the highest Saof 13.90%/K(@623 K)and the ultimate Srof 0.62%/K(@298 K)are achieved based on non-TCLs of Ho^(3+).Therefore,KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor is a promising candidate for self-referenced optical thermometry.展开更多
A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence li...A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence lifetimes,and temperature-sensing capabilities of the phosphors were thoroughly investigated.X-ray diffraction confirms the crystalline structure of the phosphors,while photoluminescence spectra reveal a colour shift attributed to the trans fer of energy from Tb^(3+)to Eu^(3+)as the concentration of Eu^(3+)increases.The phosphors excited by UV light display a transition in colour from green to yellow,and subsequently to red,which can be used as a colour tunable phosphor in white light-emitting diode(w-LED) applications.As a novel temperature sensing material,the maximum relative sensitivity of Ca_(3)Sc_(2)Ge_(3)O_(12):Tb^(3+),Eu^(3+)phosphor is 0.1044 K-1(298 K),highlighting its potential for applications in temperature sensing.展开更多
Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 n...Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 nm laser excitation,attributed to the^(4)S_(3/2)→^(4)I_(15/2)transition.By increasing the content of Ca^(2+),the crystal field regulation of rare earth ions is realized and the luminescence enhancement is induced,which is manifested by the increase of^(2)H_(11/2),^(4)S_(3/2)→^(4)I_(15/2)emission.Furthermore,the temperature sensing sensitivities of C_(0.6)S_(1.4)N:Er,Tm and C_(0.6)S_(1.4)N:Er,Tm based on non-thermally coupled energy levels were studied.Finally,an anti-counterfeiting imprint was prepared using phosphors,which have high brightness and excellent photothermal stability.This work not only confirms that closer ionic radii substitution enables to increase the electronic density of states,improve the crystal field symmetry and enhance the luminescence,but also provides a promising phosphor system for temperature sensing and anti-counterfeiting applications,opening up new prospects in the optimization of the optical properties of phosphors.展开更多
Compounds of Sr3Al2O6 ： Eu, SrgAl14O25 ： Eu, and BaZnSiO4 ： Eu were synthesized by high-temperature solid state reactions. The doping Eu^3 ＋ ions were partially reduced to Eu^2＋ in Sr4Al14O25：Eu and BaZnSiOg：Eu...Compounds of Sr3Al2O6 ： Eu, SrgAl14O25 ： Eu, and BaZnSiO4 ： Eu were synthesized by high-temperature solid state reactions. The doping Eu^3 ＋ ions were partially reduced to Eu^2＋ in Sr4Al14O25：Eu and BaZnSiOg：Eu prepared in an oxidizing atmosphere, N^2 ＋ O2. However, such an abnormal reduction process could not be performed in Sr3Al2O6：Eu, which was also prepared in an atmosphere of N^2 ＋ O2. Moreover, even though Sr3A1EO6：Eu was synthesized in a reducing condition CO, only part of the Eu^3 ＋ ions was reduced to Eu^2 ＋ . The existence of trivalent and divalent europium ions was confirmed by photoluminescent spectra. The different valence-change behaviors of europium ions in the hosts were attributed to the difference in host crystal structures. The higher the crystal structure stiffness, the easier the reduction process from Eu^3 ＋ to Eu^2 ＋ .展开更多
Yellow-emitting YAG：Ce3＋ nanocrystalline phosphors were prepared by citrate sol-gel combustion method using citric acid as the fuel and chelating agent. The influence of mole ratio of citric acid to metallic ions （...Yellow-emitting YAG：Ce3＋ nanocrystalline phosphors were prepared by citrate sol-gel combustion method using citric acid as the fuel and chelating agent. The influence of mole ratio of citric acid to metallic ions （MRCM）, pH value of the solution, calcination temperature and Ce-doped concentration on the structures and properties of as-prepared powders were investigated in detail. Higher crystallinity and better luminescence performance powders were obtained at MRCM=2, pH=3 and the calcination temperature of 1200 ℃. The phosphors exhibited the charactefistc broadband visible luminescence of YAG：Ce. The optimum concentration of Ce3＋ was 1.0 tool.%, and the concentration quenching was derived from the reciprocity between electric dipole and electric quadrupole （d-q）. Especially, the pH value of the solution was a key factor to obtain a stable sol-gel system and then obtain pure and homogeneous rare earth ions doped YAG phosphors at a lower tem- perature. The Y3Al5O12：Ce0.03 phosphor with optimized synthesis-condition and composition had a similar luminescence intensity with the commercial phosphor YAG：Ce.展开更多
We synthesized NaY(MoO4)2:Eu3+phosphors of different doping concentrations by a molten salt method.This facile way possesses advantages such as simple process,lower calcination temperature(350℃)and small particle siz...We synthesized NaY(MoO4)2:Eu3+phosphors of different doping concentrations by a molten salt method.This facile way possesses advantages such as simple process,lower calcination temperature(350℃)and small particle size(70 nm).The crystal system is tetragonal phase and crystal lattice is body centered.The photo luminescence measurements including emission spectra,excitation spectra and fluorescence decay curves were carried out,elucidating that NaY(MoO4)2:Eu3+can be effectively excited by near UV and blue light.Moreover,it can be concluded that Eu3+energy transfer type is exchange interaction.Huang-Rhys factor and the critical energy transfer distance(Rc)were calculated to be 0.043 and 0.995 nm,respectively.Auzel’s model was used to obtain the intrinsic radiative transition lifetime of5 D0 level(τ0=0.923 ms).Furthermore,a calculation method was used to calculate refractive index n of nontransparent NaY(MoO4)2:1 mol%Eu3+phosphor,and n was obtained to be 1.86.展开更多
As new light sources for next-generation illumination, white light-emitting diodes（WLEDs） have been extensively developed and are commercially available due to their excellent advantages, such as high efficiency, en...As new light sources for next-generation illumination, white light-emitting diodes（WLEDs） have been extensively developed and are commercially available due to their excellent advantages, such as high efficiency, energy-saving, compactness, long operational lifetime and environmental friendliness. Currently, WLEDs with high color rendering are mainly based on wavelength conversion by one or more phosphor materials. In this review, the recent developments of phosphors for WLEDs were introduced combined with the relative work of our group. The common methods for generating white light for blue/ultraviolet（UV） WLEDs were summarized, including：（1） optimizing the commercially used phosphors;（2） developing some new phosphors based on UV LEDs chips;（3） realizing white light emission based on single host. Moreover, some typical new developed phosphors and their luminescence properties were introduced.展开更多
Photo-stimulated luminescence(PSL) is the process in which trapped charges are released by photons and produce luminescence through recombination. The variegated optical characteristics of photostimulated phosphors(PS...Photo-stimulated luminescence(PSL) is the process in which trapped charges are released by photons and produce luminescence through recombination. The variegated optical characteristics of photostimulated phosphors(PSPs) have drawn increasing attention and a large body of work encompassing mechanism and application of PSPs has been addressed. The optical data storage capacity resulting from abundant defect states enables PSPs to be applied to information storage. Moreover, PSPs provide potential application for anti-counterfeiting, as color changes due to the tunneling process. Recently, near infrared(NIR) light PSPs have been developed, exhibiting enormous potential for in vivo bio-imaging, as the stable and high noise-signal ratio characteristic of PSL. In this review, we devote to introducing the development and process of PSPs, and the challenge and future advance have also been demonstrated.展开更多
Er^(3+)-Yb^(3+)-Li^+:Gd_2(MoO_4)_3 and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors, synthesized by chemical co-precipitation technique were characterized through XRD,FESEM,dynamic light scattering(DLS),diffuse...Er^(3+)-Yb^(3+)-Li^+:Gd_2(MoO_4)_3 and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors, synthesized by chemical co-precipitation technique were characterized through XRD,FESEM,dynamic light scattering(DLS),diffuse reflectance, photoluminescence, photometric and decay time analysis. The enhancement of about～28, ～149 and ～351 times in the green upconversion emission band is observed for the optimized Er^(3+)-Yb^(3+),Er^(3+)-Yb^(3+)-Li^+ and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors in comparison to the singly Er^(3+) doped nanophosphors. The electric dipole-dipole interaction is found to be responsible for the concentration quenching. The temperature dependent behaviour of the two green thermally coupled levels of the Er^(3+) ions based on the fluorescence intensity ratio technique was studied. The maximum sensor sensitivity ～38.7 × 10^(-3) K^(-1) at 473 K for optimized Er^(3+)-Yb^(3+)-Zn^(2+) codoped Gd_2(MoO_4)_3 nanophosphors is reported with maximum population redistribution ability～88% among the ~2H_(11/2) and ~4S_(3/2) levels.展开更多
A novel orange-red emitting Ba3 Y4 O9：Sm^（3＋） phosphors were prepared by a high temperature solidstate reaction in air. X-ray diffraction（XRD）, photoluminescence spectra, fluorescence decay and temperature-depen...A novel orange-red emitting Ba3 Y4 O9：Sm^（3＋） phosphors were prepared by a high temperature solidstate reaction in air. X-ray diffraction（XRD）, photoluminescence spectra, fluorescence decay and temperature-dependent emission spectra were utilized to characterize the structure and luminescence properties. The results show that the excitation spectrum includes a series of linear peaks at350, 367, 382, 410, 424, 445, 470 and 495 nm, respectively. Under 410 nm excitation, the emission peaks were located at 574 nm（~4 G（5/2）-~6 H（5/2））, 608 nm（~4 G（5/2）-~6 H（7/2））,659 nm（~4 G（5/2）-~6 H（9/2）） and722 nm（~4 G（5/2）-~6 H（11/2））, respectively. The concentration quenching occurs when x equals 0.08 for Ba3 Y（4-x）O9：xSm^（3＋） phosphor and its mechanism is ascribed to the dipole-dipole interaction. The chromaticity coordinates of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor are in the orange-red region. The temperature-dependent study shows that this phosphor has excellent luminescence thermal-stability.And the luminescence intensity of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor at 473 K only declines by about25.75% of its initial intensity. The experimental data indicate that Ba3 Y4 O9：Sm^（3＋） phosphor may be promising as an orange-red emitting phosphor for white light emitting diodes.展开更多
In the present study,Sm^(3+)activated inorganic orthophosphate CsMgPO_(4)(CSMP)phosphors were prepared by adopting a solid-state reaction method.The structural phase purity and morphological features were studied by X...In the present study,Sm^(3+)activated inorganic orthophosphate CsMgPO_(4)(CSMP)phosphors were prepared by adopting a solid-state reaction method.The structural phase purity and morphological features were studied by X-ray powder diffraction(XRD)and scanning electron microscopy(SEM),respectively.The molecular structure and vibrational modes were substantiated with the Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy characterization.The optical bandgap of the host and Sm^(3+)doped phosphors was deduced from the diffused reflectance(DR)spectra with a typical value of 5.72 eV and a small variation is observed with increasing concentrations.A systematic study of photoluminescence(PL)properties of Sm^(3+)doped CSMP phosphors was carried out.From the room temperature excitation and emission spectra,it is found that the phosphor emits in the orange rich red light under the suitable excitation of 402 nm in the UV region and concentration quenching occurs at x=0.02 doping level.The emission peaks observed at around 562,598 and 644 nm confirm the characteristic Sm^(3+)4 f-4 f transitions.The temperature-dependent photoluminescence(TD-PL)of the x=0.02(optimum doping)is recorded from 30 to 210℃,showing good thermal stability even at 150℃.The thermal quenching mechanisms are discussed based on the configuration coordinate model of excitation and emission.The prepared phosphors are found to exhibit near thermal stability compared to the commercially available red phosphors.PL decay time and quantum efficiency were measured.The colour coordinates are found to lie in the orangish-red region of the colour space.Thus the prepared phosphors CSMP:x Sm^(3+)can be useful as a red component in designing UV excitable chip-based phosphor-converted white LED applications.展开更多
Blue-green luminescent BaAl2O4：Eu2＋,Dy3＋ phosphor powders were synthesized via combustion synthesis method assisted by microwave irradiation in air. The phosphors were characterized by X-ray diffraction （XRD）, sc...Blue-green luminescent BaAl2O4：Eu2＋,Dy3＋ phosphor powders were synthesized via combustion synthesis method assisted by microwave irradiation in air. The phosphors were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and fluorescence spectrophotometer. The XRD results revealed that when the concentration of urea was over 3 times higher than theoretical quantities, a BaAl2O4 single hexagonal phase was obtained. The SEM results revealed that the surface of the BaAl2O4：Eu2＋,Dy3＋ powder samples showed lots of voids and pores. The BaAl2O4：Eu2＋,Dy3＋ phosphors exhibited a broad emission band of main peak at 496 nm and a shoulder peak at 426 nm under excitation of 337 nm. The BaAl2O4：Eu2＋,Dy3＋ phosphors at the Eu2＋ concentration of 1 mol.% showed the strongest luminescent intensity. Long afterglow phosphorescence was observed in the dark with naked eyes after the removal of the excitation source.展开更多
YAG：Ce,Sm spherical phosphors were synthesized by malic acid sol-gel method. The formation process of crystalline was characterized by X-ray diffraction （XRD） technique. The influence of Sm3＋ doping on the lumines...YAG：Ce,Sm spherical phosphors were synthesized by malic acid sol-gel method. The formation process of crystalline was characterized by X-ray diffraction （XRD） technique. The influence of Sm3＋ doping on the luminescent intensity and the morphology of phosphors were studied by fluorescence spectrum and scanning electron microscopy （SEM） techniques, respectively. The results indicated that the size of spherical powders was about 100 um calcined at 1200 ℃ for 3 h. The emission spectra of phosphors showed gradual red-shift from 525 to 540 um with the increase of doping concentration of Sm3＋ ion. A broadband emission specmtm of Ce3＋ ion appeared at 540 nm, and a series of emission peaks corresponding to the 4Gs/2-＋6Hd transition of Sm3＋ ion also appeared at 617 um with the doping of Sm3＋. The red component of YAG：Ce phosphors increased with the doping of Sm3＋.展开更多
Ce3＋-activated yttrium aluminum garnet （YAG） was prepared by the solid-state reaction, in which H3BO3, LiF, NaF, KF and BaF2 were used as the fluxes. The effect of fluxes on optical properties of phosphors was stud...Ce3＋-activated yttrium aluminum garnet （YAG） was prepared by the solid-state reaction, in which H3BO3, LiF, NaF, KF and BaF2 were used as the fluxes. The effect of fluxes on optical properties of phosphors was studied in detail, especially the fluxes of alkali fluorides, which could enhance the emission intensity and change the wavelength of emission peaks. Among these YAG：Ce phosphors, the phosphor sintered with H3BO3 and NaF exhibited the strongest emission. The emission peaks of phosphors prepared with fluxes from LiF to KF were shifted to long wavelength. The effect of NaF concentration on the emission intensity of YAG：Ce was also investigated. The value of emission intensity reached the maximum when the concentration of NaF was 0.5%.展开更多
文摘This paper reports the preparation of yttrium oxide(Y_(2)O_(3))doped with various concentrations of Er^(3+)using high temperature synthesis method.Photoluminescence(PL)emission spectra of the samples were recorded at an excitation of 980 nm laser source.Two prominent peaks centered at 484 nm and 574 nm were found and attributed to the^(2)P3/2→^(4)I_(11/2)and^(4)S_(3/2)→^(4)I_(15/2),respectively.The sample with 2.5 mol%of Er^(3+)provided the optimum intensity in emission spectra.The sample with optimum PL emission was investigated for its thermoluminescence(TL)glow curve exhibited the second order kinetics.The peak TL intensity was found around 236°C,i.e.,towards high temperature which supports the fact of formation of deeper traps.Therefore,the material taken may be regarded as a good candidate for light emitting diode(LED)applications.
基金supported by the Natural Science Research Project of Anhui Provincial Education Department for Excellent Young Scholars(Grant No.2024AH030007)the National Natural Science Foundation of China(Grant No.52202001).
文摘Cr^(3+)-activated phosphors have attracted significant attention for their tunable emission,spanning narrow-band red to broadband near-infrared(NIR)luminescence,depending on the crystal field environment.Here,we report the realization of wideband NIR emission in Cr^(3+)-doped GaScO_(3)(GaScO_(3):Cr^(3+))phosphors with perovskite structure.The phosphors were synthesized by traditional solid-state reaction method.The first-principles calculations were conducted and the results demonstrate that the octahedral[GaO_(6)]sites exhibit relatively weak crystal field strength(Dq/B≈2.2),facilitating efficient spin-allowed transitions of Cr^(3+)from the^(4)T_(2)state to the^(4)A_(2)state.The photoluminescence spectroscopy revealed an exceptionally broad NIR emission band from a range of 700 nm-1200 nm with full width at half maximum(FWHM)of 145 nm under 465-nm excitation.Overall,these results highlight the viability of GaScO_(3):Cr^(3+)as a highly promising material for wideband NIR applications.
文摘To meet the high demands of modern technology for temperature sensors,Lu_(2)WO_(6):Sm^(3+)self-activated phosphors were selected to design four-mode optical thermometers.A comprehensive investigation was conducted on the synthetic method,structural and luminescent characteristics,and energy transfer mechanism([WO6]6-→Sm^(3+)). Due to the different temperature responses of two emission centers([WO6]6-and Sm^(3+)),the temperature sensing capability of Lu_(2)WO_(6):Sm^(3+)phosphors was studied.Fluorescence intensity(FI),fluorescence intensity ratio(FIR),Commission Internationale de L'Eclairage coordinates and excitation intensity ratio are the four modes for temperature sensing,and their maximum relative sensitivities are 2.62%/K(350 K),2.06%/K(320 K),0.67%/K(329 K) and 2.42%/K(303 K),respectively.Furthermore,within 303-483 K temperature range,the relative sensitivities based on FI and FIR are bigger than 1.67%/K and 1.16%/K,respectively.Our findings suggest that Lu_(2)WO_(6):Sm^(3+)phosphors with four temperature measurement modes might be applied in multi-mode self-calibration optical thermometers.
基金Project supported by the National Natural Science Foundation of China(52272143,51902063)the Guangdong Basic and Applied Basic Research Foundation(2023A1515010166,2023A1515010866,2021A1515110404)the Major Science and Technology Project of Jiangxi Province(20223AAE01003)。
文摘Cr^(3+)-activated spinel-type phosphors have great potential in different application scenes due to their unique sharp and far-red(FR)emission.However,the multi-functionalization of these phosphors is still limited by their unsatisfied comprehensive properties.Herein,a simple composition engineering was used to explore versatile phosphors,using Ga^(3+)to substitute Al^(3+)to improve the optical performances of spinel LiAl5-xGa_(x)O_(8):Cr^(3+).The substitution of Ga^(3+)evidently affects the crystal field environment of Cr^(3+)and further accounts for the luminescence optimization.Using the optimized phosphor,two sensitive thermometers based on fluorescence intensity ratio(FIR)technique were explored on account of the different temperature dependencies of^(4)T_(2)→^(4)A_(2)and2E→^(4)A_(2)emission and of R2and R1emission.The maximum relative sensitivity Sr are 1.29%/K at 323 K and 1.94%/K at 298 K,respectively,which are superior to that of the Ga^(3+)-unsubstituted one.Besides,the Ga^(3+)→Al^(3+)substitutions endow the resultant phosphors with larger atomic number(Zeff)and theoretical density,which is more conducive to improving X-ray-stimulated emission for X-ray detection.Finally,the potential applications of the developed phosphor are also reflected in plant growth and night vision surveillance,as it is shown to be capable of matching with the absorption of phytochrome PFRand visualizing objects in the dark.This contribution not only proves that the developed LiAl5-xGa_(x)O_(8):Cr^(3+)FR phosphors are promising versatile platforms,but also provides an essential guidance for designing more novel multi-functional materials.
基金financially supported by the Caiyun Postdoctoral Innovation Project(No.C615300504089)Yunnan Fundamental Research Project(No.202401AS070128)National Natural Science Foundation of China(No.22165031).
文摘Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity remain rare.Herein,NaLnTe_(2)O_(7):Eu^(3+)(Ln=Y and Gd)phosphors were synthesized using a rapid microwave-assisted solidstate(MASS)method to fulfill these applications.Under 395 nm excitation,NaLnTe_(2)O_(7):Eu^(3+)exhibit the characteristic ^(5)D_(0)→^(7)F_(J)(J=1–4)transitions of Eu^(3+).Substituting Gd^(3+) for Y^(3+) enhances the luminescence by approximately 2.42 times.Structural analyses reveal that the improved luminescent properties are attributed to the more distorted and appropriate coordination environment in NaGdTe_(2)O_(7):Eu^(3+).Finally,white-LEDs using NaGdTe_(2)O_(7):Eu^(3+)as the red-component produce white light with high Ra of 89.Furthermore,the distinct thermal responses of the ^(5)D_(0)→^(7)F_(J) transitions enable NaLnTe_(2)O_(7):Eu^(3+)to function as temperature sensors via fluorescence intensity ratio(FIR)strategy.NaYTe_(2)O_(7):Eu^(3+)possesses the maximum relative/absolute sensitivity of 1.45%/15.93%K^(-1),whereas NaGdTe_(2)O_(7):Eu^(3+)achieves the maximum relative/absolute sensitivity of 1.53%/30.24% K^(-1).This work highlights the significance of cationic substitution in enhancing luminescent properties for multifunctional applications.
基金supported by the National Natural Science Foundation of China(52403403)Guizhou Provincial Basic Research Program(Natural Science)(Qian ke he ji chu-ZK2024 YiBan 095)。
文摘Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material was successfully synthesized and Er^(3+)ions were successfully doped into the main lattice.This doping does change the basic structure of the crystal.BaLaGaO_(4):Er^(3+)phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light.The optimal doping concentration is found to be x=0.04.To quantify the temperature sensitivity of the phosphor,the fluorescence intensity ratio method was used.Within the temperature range of 298-473 K,the maximum relative sensitivities are 1.35%/K(298 K,381 nm)and 1.45%/K(298 K,980 nm),respectively.The maximum absolute sensitivities are 0.67%/K(473 K,381 nm)and 0.69%/K(473 K,980 nm),respectively.Finally,white light-emitting diodes(WLEDs)with a high colour index of Ra=82and a relatively low correlated colour temperature of CCT=5064 K are obtained by integrating the synthesized BaLaGaO_(4):0.04Er^(3+)green phosphor into warm WLEDs devices.These results suggest that Er^(3+)-activated BaLaGaO_(4)multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.
基金supported by the National Natural Science Foundation of China(61865003)。
文摘To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through solid reaction process.The crystal structure,up-conversion luminescence,energy transfer,thermal stability and optical temperature sensing performances were studied in detail.Under 980 nm laser excitation,the KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor exhibits distinctive emission bands of Ho^(3+)at545,660,and 755 nm,and excellent illuminant performance.Based on the thermally coupled levels(TCLs)of Ho^(3+),both the relative sensitivity(S_(r))and absolute sensitivity(S_(a))display similar change trends,with the highest values of 6.73%/K(@298 K)and 5.69%/K(@298 K),respectively.Furthermore,the highest Saof 13.90%/K(@623 K)and the ultimate Srof 0.62%/K(@298 K)are achieved based on non-TCLs of Ho^(3+).Therefore,KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor is a promising candidate for self-referenced optical thermometry.
基金Project supported by the National Natural Science Foundation of China (52274273)。
文摘A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence lifetimes,and temperature-sensing capabilities of the phosphors were thoroughly investigated.X-ray diffraction confirms the crystalline structure of the phosphors,while photoluminescence spectra reveal a colour shift attributed to the trans fer of energy from Tb^(3+)to Eu^(3+)as the concentration of Eu^(3+)increases.The phosphors excited by UV light display a transition in colour from green to yellow,and subsequently to red,which can be used as a colour tunable phosphor in white light-emitting diode(w-LED) applications.As a novel temperature sensing material,the maximum relative sensitivity of Ca_(3)Sc_(2)Ge_(3)O_(12):Tb^(3+),Eu^(3+)phosphor is 0.1044 K-1(298 K),highlighting its potential for applications in temperature sensing.
基金Project supported by the Science and Technology International Cooperation Project of Qinghai Province (2022-HZ-807)the Open Project Salt Lake Chemical Engineering Research Complex,Qinghai University (2023-DXSSZZ-04)。
文摘Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 nm laser excitation,attributed to the^(4)S_(3/2)→^(4)I_(15/2)transition.By increasing the content of Ca^(2+),the crystal field regulation of rare earth ions is realized and the luminescence enhancement is induced,which is manifested by the increase of^(2)H_(11/2),^(4)S_(3/2)→^(4)I_(15/2)emission.Furthermore,the temperature sensing sensitivities of C_(0.6)S_(1.4)N:Er,Tm and C_(0.6)S_(1.4)N:Er,Tm based on non-thermally coupled energy levels were studied.Finally,an anti-counterfeiting imprint was prepared using phosphors,which have high brightness and excellent photothermal stability.This work not only confirms that closer ionic radii substitution enables to increase the electronic density of states,improve the crystal field symmetry and enhance the luminescence,but also provides a promising phosphor system for temperature sensing and anti-counterfeiting applications,opening up new prospects in the optimization of the optical properties of phosphors.
基金Project supported bythe National Natural Science Foundation of China (50125258 ,60377040)
文摘Compounds of Sr3Al2O6 ： Eu, SrgAl14O25 ： Eu, and BaZnSiO4 ： Eu were synthesized by high-temperature solid state reactions. The doping Eu^3 ＋ ions were partially reduced to Eu^2＋ in Sr4Al14O25：Eu and BaZnSiOg：Eu prepared in an oxidizing atmosphere, N^2 ＋ O2. However, such an abnormal reduction process could not be performed in Sr3Al2O6：Eu, which was also prepared in an atmosphere of N^2 ＋ O2. Moreover, even though Sr3A1EO6：Eu was synthesized in a reducing condition CO, only part of the Eu^3 ＋ ions was reduced to Eu^2 ＋ . The existence of trivalent and divalent europium ions was confirmed by photoluminescent spectra. The different valence-change behaviors of europium ions in the hosts were attributed to the difference in host crystal structures. The higher the crystal structure stiffness, the easier the reduction process from Eu^3 ＋ to Eu^2 ＋ .
基金Project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)Jiangsu Provincial Natural Sciences Fund (BK2007724)
文摘Yellow-emitting YAG：Ce3＋ nanocrystalline phosphors were prepared by citrate sol-gel combustion method using citric acid as the fuel and chelating agent. The influence of mole ratio of citric acid to metallic ions （MRCM）, pH value of the solution, calcination temperature and Ce-doped concentration on the structures and properties of as-prepared powders were investigated in detail. Higher crystallinity and better luminescence performance powders were obtained at MRCM=2, pH=3 and the calcination temperature of 1200 ℃. The phosphors exhibited the charactefistc broadband visible luminescence of YAG：Ce. The optimum concentration of Ce3＋ was 1.0 tool.%, and the concentration quenching was derived from the reciprocity between electric dipole and electric quadrupole （d-q）. Especially, the pH value of the solution was a key factor to obtain a stable sol-gel system and then obtain pure and homogeneous rare earth ions doped YAG phosphors at a lower tem- perature. The Y3Al5O12：Ce0.03 phosphor with optimized synthesis-condition and composition had a similar luminescence intensity with the commercial phosphor YAG：Ce.
基金Project supported by the National Natural Science Foundation of China(51002041)
文摘We synthesized NaY(MoO4)2:Eu3+phosphors of different doping concentrations by a molten salt method.This facile way possesses advantages such as simple process,lower calcination temperature(350℃)and small particle size(70 nm).The crystal system is tetragonal phase and crystal lattice is body centered.The photo luminescence measurements including emission spectra,excitation spectra and fluorescence decay curves were carried out,elucidating that NaY(MoO4)2:Eu3+can be effectively excited by near UV and blue light.Moreover,it can be concluded that Eu3+energy transfer type is exchange interaction.Huang-Rhys factor and the critical energy transfer distance(Rc)were calculated to be 0.043 and 0.995 nm,respectively.Auzel’s model was used to obtain the intrinsic radiative transition lifetime of5 D0 level(τ0=0.923 ms).Furthermore,a calculation method was used to calculate refractive index n of nontransparent NaY(MoO4)2:1 mol%Eu3+phosphor,and n was obtained to be 1.86.
基金supported by the National Science Foundation for Distinguished Young Scholars(50925206)the Specialized Research Fund for the Doctoral Program of Higher Education(20120211130003)+1 种基金the National Natural Science Foundation of China(51372105)the Fundamental Research Funds for the Central Universities(lzujbky-2014-231)
文摘As new light sources for next-generation illumination, white light-emitting diodes（WLEDs） have been extensively developed and are commercially available due to their excellent advantages, such as high efficiency, energy-saving, compactness, long operational lifetime and environmental friendliness. Currently, WLEDs with high color rendering are mainly based on wavelength conversion by one or more phosphor materials. In this review, the recent developments of phosphors for WLEDs were introduced combined with the relative work of our group. The common methods for generating white light for blue/ultraviolet（UV） WLEDs were summarized, including：（1） optimizing the commercially used phosphors;（2） developing some new phosphors based on UV LEDs chips;（3） realizing white light emission based on single host. Moreover, some typical new developed phosphors and their luminescence properties were introduced.
基金Project supported by the National Natural Science Foundation of China(61565009,11664022,11804038)the Foundation of Natural Science of Yunnan Province(2016FB088)+3 种基金the Reserve Talents Project of Yunnan Province(2017HB011)the Young Talents Support Program of Faculty of Materials Science and Engineering,Kunming University of Science and Technology(14078342)Chongqing Natural Science Foundation(cstc2017jcyjAX0418,cstc2018jcyjAX0569)Foundation of Chongqing University of Arts and Sciences(R2016DQ10)
文摘Photo-stimulated luminescence(PSL) is the process in which trapped charges are released by photons and produce luminescence through recombination. The variegated optical characteristics of photostimulated phosphors(PSPs) have drawn increasing attention and a large body of work encompassing mechanism and application of PSPs has been addressed. The optical data storage capacity resulting from abundant defect states enables PSPs to be applied to information storage. Moreover, PSPs provide potential application for anti-counterfeiting, as color changes due to the tunneling process. Recently, near infrared(NIR) light PSPs have been developed, exhibiting enormous potential for in vivo bio-imaging, as the stable and high noise-signal ratio characteristic of PSL. In this review, we devote to introducing the development and process of PSPs, and the challenge and future advance have also been demonstrated.
基金Project supported by Council of Scientific&Industrial Research(CSIR),New Delhi,India(03(1354)/16/EMR-II)
文摘Er^(3+)-Yb^(3+)-Li^+:Gd_2(MoO_4)_3 and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors, synthesized by chemical co-precipitation technique were characterized through XRD,FESEM,dynamic light scattering(DLS),diffuse reflectance, photoluminescence, photometric and decay time analysis. The enhancement of about～28, ～149 and ～351 times in the green upconversion emission band is observed for the optimized Er^(3+)-Yb^(3+),Er^(3+)-Yb^(3+)-Li^+ and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors in comparison to the singly Er^(3+) doped nanophosphors. The electric dipole-dipole interaction is found to be responsible for the concentration quenching. The temperature dependent behaviour of the two green thermally coupled levels of the Er^(3+) ions based on the fluorescence intensity ratio technique was studied. The maximum sensor sensitivity ～38.7 × 10^(-3) K^(-1) at 473 K for optimized Er^(3+)-Yb^(3+)-Zn^(2+) codoped Gd_2(MoO_4)_3 nanophosphors is reported with maximum population redistribution ability～88% among the ~2H_(11/2) and ~4S_(3/2) levels.
基金supported by the National Key Research and Development Program of China(2016YFB0701003)Key Program of the Frontier Science of the Chinese Academy of Sciences(YZDY-SSW-JSC018)+1 种基金National Natural Science Foundation of China(51402288)Natural Science Foundation of Liaoning Province(201602674)
文摘A novel orange-red emitting Ba3 Y4 O9：Sm^（3＋） phosphors were prepared by a high temperature solidstate reaction in air. X-ray diffraction（XRD）, photoluminescence spectra, fluorescence decay and temperature-dependent emission spectra were utilized to characterize the structure and luminescence properties. The results show that the excitation spectrum includes a series of linear peaks at350, 367, 382, 410, 424, 445, 470 and 495 nm, respectively. Under 410 nm excitation, the emission peaks were located at 574 nm（~4 G（5/2）-~6 H（5/2））, 608 nm（~4 G（5/2）-~6 H（7/2））,659 nm（~4 G（5/2）-~6 H（9/2）） and722 nm（~4 G（5/2）-~6 H（11/2））, respectively. The concentration quenching occurs when x equals 0.08 for Ba3 Y（4-x）O9：xSm^（3＋） phosphor and its mechanism is ascribed to the dipole-dipole interaction. The chromaticity coordinates of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor are in the orange-red region. The temperature-dependent study shows that this phosphor has excellent luminescence thermal-stability.And the luminescence intensity of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor at 473 K only declines by about25.75% of its initial intensity. The experimental data indicate that Ba3 Y4 O9：Sm^（3＋） phosphor may be promising as an orange-red emitting phosphor for white light emitting diodes.
文摘In the present study,Sm^(3+)activated inorganic orthophosphate CsMgPO_(4)(CSMP)phosphors were prepared by adopting a solid-state reaction method.The structural phase purity and morphological features were studied by X-ray powder diffraction(XRD)and scanning electron microscopy(SEM),respectively.The molecular structure and vibrational modes were substantiated with the Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy characterization.The optical bandgap of the host and Sm^(3+)doped phosphors was deduced from the diffused reflectance(DR)spectra with a typical value of 5.72 eV and a small variation is observed with increasing concentrations.A systematic study of photoluminescence(PL)properties of Sm^(3+)doped CSMP phosphors was carried out.From the room temperature excitation and emission spectra,it is found that the phosphor emits in the orange rich red light under the suitable excitation of 402 nm in the UV region and concentration quenching occurs at x=0.02 doping level.The emission peaks observed at around 562,598 and 644 nm confirm the characteristic Sm^(3+)4 f-4 f transitions.The temperature-dependent photoluminescence(TD-PL)of the x=0.02(optimum doping)is recorded from 30 to 210℃,showing good thermal stability even at 150℃.The thermal quenching mechanisms are discussed based on the configuration coordinate model of excitation and emission.The prepared phosphors are found to exhibit near thermal stability compared to the commercially available red phosphors.PL decay time and quantum efficiency were measured.The colour coordinates are found to lie in the orangish-red region of the colour space.Thus the prepared phosphors CSMP:x Sm^(3+)can be useful as a red component in designing UV excitable chip-based phosphor-converted white LED applications.
基金supported by the National Natural Science Foundation of China (60477034)
文摘Blue-green luminescent BaAl2O4：Eu2＋,Dy3＋ phosphor powders were synthesized via combustion synthesis method assisted by microwave irradiation in air. The phosphors were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and fluorescence spectrophotometer. The XRD results revealed that when the concentration of urea was over 3 times higher than theoretical quantities, a BaAl2O4 single hexagonal phase was obtained. The SEM results revealed that the surface of the BaAl2O4：Eu2＋,Dy3＋ powder samples showed lots of voids and pores. The BaAl2O4：Eu2＋,Dy3＋ phosphors exhibited a broad emission band of main peak at 496 nm and a shoulder peak at 426 nm under excitation of 337 nm. The BaAl2O4：Eu2＋,Dy3＋ phosphors at the Eu2＋ concentration of 1 mol.% showed the strongest luminescent intensity. Long afterglow phosphorescence was observed in the dark with naked eyes after the removal of the excitation source.
基金Project supported by the Scientific and Technological Department of Jilin Province (20120117)the Scientific and Technological Bureau of Changchun City (11KZ42)the project of Jilin development and Reform Commission (2011FGW03)
文摘YAG：Ce,Sm spherical phosphors were synthesized by malic acid sol-gel method. The formation process of crystalline was characterized by X-ray diffraction （XRD） technique. The influence of Sm3＋ doping on the luminescent intensity and the morphology of phosphors were studied by fluorescence spectrum and scanning electron microscopy （SEM） techniques, respectively. The results indicated that the size of spherical powders was about 100 um calcined at 1200 ℃ for 3 h. The emission spectra of phosphors showed gradual red-shift from 525 to 540 um with the increase of doping concentration of Sm3＋ ion. A broadband emission specmtm of Ce3＋ ion appeared at 540 nm, and a series of emission peaks corresponding to the 4Gs/2-＋6Hd transition of Sm3＋ ion also appeared at 617 um with the doping of Sm3＋. The red component of YAG：Ce phosphors increased with the doping of Sm3＋.
基金supported by the Science Technology Project of Zhejiang Province (2008C21153)the National Natural Science Foundation of China (60508014 and 50772102)+1 种基金Program for New Century Excellent Talents in University (NCET-07-0786)the Nature Science Foundation of Zhejiang Province (R406007)
文摘Ce3＋-activated yttrium aluminum garnet （YAG） was prepared by the solid-state reaction, in which H3BO3, LiF, NaF, KF and BaF2 were used as the fluxes. The effect of fluxes on optical properties of phosphors was studied in detail, especially the fluxes of alkali fluorides, which could enhance the emission intensity and change the wavelength of emission peaks. Among these YAG：Ce phosphors, the phosphor sintered with H3BO3 and NaF exhibited the strongest emission. The emission peaks of phosphors prepared with fluxes from LiF to KF were shifted to long wavelength. The effect of NaF concentration on the emission intensity of YAG：Ce was also investigated. The value of emission intensity reached the maximum when the concentration of NaF was 0.5%.
