Rare earth luminescent materials have attracted significant attention due to their wide-ranging applications in the field of optoelectronics. This study aims to delve into the electronic structure and optical properti...Rare earth luminescent materials have attracted significant attention due to their wide-ranging applications in the field of optoelectronics. This study aims to delve into the electronic structure and optical properties of rare earth luminescent materials, with the goal of uncovering their importance in luminescence mechanisms and applications. Through theoretical calculations and experimental methods, we conducted in-depth analyses on materials composed of various rare earth elements. Regarding electronic structure, we utilized computational techniques such as density functional theory to investigate the band structure, valence state distribution, and electronic density of states of rare earth luminescent materials. The results indicate that the electronic structural differences among different rare earth elements notably influence their luminescence performance, providing crucial clues for explaining the luminescence mechanism. In terms of optical properties, we systematically examined the material’s optical behaviors through fluorescence spectroscopy, absorption spectroscopy, and other experimental approaches. We found that rare earth luminescent materials exhibit distinct absorption and emission characteristics at different wavelengths, closely related to the transition processes of their electronic energy levels. Furthermore, we studied the influence of varying doping concentrations and impurities on the material’s optical properties. Experimental outcomes reveal that appropriate doping can effectively regulate the emission intensity and wavelength, offering greater possibilities for material applications. In summary, this study comprehensively analyzed the electronic structure and optical properties of rare earth luminescent materials, providing deep insights into understanding their luminescence mechanisms and potential value in optoelectronic applications. In the future, these research findings will serve as crucial references for the technological advancement in fields such as LEDs, lasers, and bioimaging.展开更多
A novel Eu^3＋ rare earth complex, composed of 4 - hydroxybenzolate acid and 1, 10 - phenanthroline ligands was synthesized. The apparent morphology, composition, thermal stability and fluorescent property of the rare...A novel Eu^3＋ rare earth complex, composed of 4 - hydroxybenzolate acid and 1, 10 - phenanthroline ligands was synthesized. The apparent morphology, composition, thermal stability and fluorescent property of the rare earth complex were measured by TEM, Element analysis, IR, TG and Fluorescence spectrometer. The results indicated that this rare earth complex has sphere-like morphology and its diameter was about 100 nm. The complex has good thermal stability due to the strong coordination between the Eu^3＋ ions and the ligands. Based on the composition analysis, the complex structure formula was： Eu （HOC6 H4 COI）3 （phen） ·H2O Fluorescence spectra showed that the rare earth complex emission peaks were corresponding to the transition of ^5D0→7FJ（J=0,1,2,4）,. and the highest intensity fluorescence peak was at 617 nm. The luminescent fiber was prepared by blending melt-spinning with rare earth complex and polypropylene resin. It also has a good luminescent quality, which the strongest emission peak was at 619 nm. It could be considered suitable for industrial application.展开更多
A new type of samarium ion activated luminescent glass ceramics with main crystal phase of melilite was prepared. The effect of heat-treatment temperature on the structure of glass ceramics was investigated by X-ray d...A new type of samarium ion activated luminescent glass ceramics with main crystal phase of melilite was prepared. The effect of heat-treatment temperature on the structure of glass ceramics was investigated by X-ray diffraction analysis（XRD）, scanning electron microscope（SEM） and fluorescence spectrometer. In the Sm^3＋ doped SrO-MgO-SiO2 glass ceramic, its excitation spectra are in the wavelength range of 350-500 nm, and its excitation peaks are at 360 nm, 374 nm, 404 nm, 417 nm, and 475 nm with the host excitation peak of 404 nm, showing a strong orange-red luminescence when using 404 nm violet to excite it, and its emission peaks are at 564 nm, 600 nm and 648 nm with the host emission peak at 600 nm. The increase in the heat-treatment temperature has no infl uence on the position of the fl uorescent spectra. However, with the increase of heat-treatment temperature, the intensity of fl uorescence spectrum shows an increasing tendency. The increase in the concentration of Sm3＋ also improves the intensity of the fl uorescent spectra. In the experimental concentration range（0.05mol%-0.30mol%）, a special concentration quenching phenomenon happens.展开更多
Polypropylene composite nonwovens containing rare-earth strontium aluminates Sr Al2O4：Eu2＋,Dy3＋ and functional additives were fabricated by the spun-bonded technique.The optical properties, morphology and mechanica...Polypropylene composite nonwovens containing rare-earth strontium aluminates Sr Al2O4：Eu2＋,Dy3＋ and functional additives were fabricated by the spun-bonded technique.The optical properties, morphology and mechanical properties of the samples were characterized.Results from scanning electron microscopy photographs（SEM） indicated that the surface of the fiber was destroyed by the addition of rare earth luminescent materials lightly but the thickness of the fiber was uniform.Differential scanning calorimetry results showed that pure polypropylene has the double crystallization peak at 162.3 and 165.1 °C.Studies from X-ray diffraction showed that the nonwoven prepared with the luminescent materials contained the α-monoclinic crystal and β crystalline phase.Furthermore, the afterglow properties were tested, which showed that the afterglow curve of the luminous nonwoven was similar to that of strontium aluminate, and the intensity was more intensive than luminous nonwoven at the beginning.The nonwoven fabricated with the luminescent material did not affect the crystal lattice of the polymer making the materials have potential applications in fluorescent lamps and field emission displays（FEDs）.展开更多
The Pr(TTA)_3phen(C_2H_5OH)quarternary complex with 2-thenoyltrifluoro-acetone(TTA), 1,10-phenanthroline(phen)and ethanol were synthesized and characterized by single-crystal X-ray diffraction. The central Pr^(3+) ion...The Pr(TTA)_3phen(C_2H_5OH)quarternary complex with 2-thenoyltrifluoro-acetone(TTA), 1,10-phenanthroline(phen)and ethanol were synthesized and characterized by single-crystal X-ray diffraction. The central Pr^(3+) ion is nine-coordinated. The infrared(IR)spectrum, diffuse reflectance(DR)spectrum and fluorescence measurements of the complex were investigated.展开更多
As a material with good biocompatibility,hydroxyapatite(HAP)can have optical properties after doping with various rare earth ions.As a biocompatible fluorescent material,doped HAP could have broad applications in biol...As a material with good biocompatibility,hydroxyapatite(HAP)can have optical properties after doping with various rare earth ions.As a biocompatible fluorescent material,doped HAP could have broad applications in biological probes,drug delivery,optoelectronic materials,fluorescence anti-counterfeiting,and other aspects.In this paper,we put forward the preparation of HAP doped with terbium(Ⅲ)ions(Tb^(3+))by hydrothermal co-precipitation.By controlling the Tb^(3+)doping content in reaction and the reaction time,the changes in HAP's structure,morphology,and luminescence properties under different conditions were studied.When the doping amount of Tb^(3+)reached an optimal value,the dipole-quadrupole would occur and the concentration would be quenched.The control experiment showed that the optimal Tb3+content was 7.5×10^(-5)mol,which showed the best fluorescence performance.HAP,a non-luminous material,was rarely used in the field of fluorescent anti-counterfeiting and photoelectric devices.We proposed to prepare a luminescent aramid/polyphenylene sulfide(ACFs/PPS)fiber paper and a new light-emitting diode(LED)using the Tb-doped HAP phosphor.The composite sample exhibited an excellent stability and fluorescence performance,which also demonstrated a possibility of HAP applications in anticounterfeiting and photoelectric.The introduction of Tb3+dopant HAP was done to give HAP optical properties and broaden the application range of HAP.展开更多
The system Al-2O-3-B-2O-3-Ce-2O-3, with Al/B ratio varying from 4.5 to 2 and Ce/(Al+B)=0.02, has been prepared at the temperature from 1 200 to 1 400℃. Relationship between luminescence and matrices in the system Al-...The system Al-2O-3-B-2O-3-Ce-2O-3, with Al/B ratio varying from 4.5 to 2 and Ce/(Al+B)=0.02, has been prepared at the temperature from 1 200 to 1 400℃. Relationship between luminescence and matrices in the system Al-2O-3-B-2O-3-Ce-2O-3 was investigated. It was found that some changes of the matrices occurred with Al/B ratio varying from 4.5 to 2. These results lead to a great change in luminescence properties, indicating variation of Ce-surroundings of crystal field. With the decrease of the ratio from 3 to 2, the excitation and emission peaks shift to shorter wavelengths. It was also found that a new type of rare earth luminescent materials was obtained with appropriate Al/B ratio.展开更多
ZnTiO3：Eu3＋ phosphors were synthesized with different concentrations of Eu3＋ doping through sol-gel method. The samples were calcined at different temperatures for 2 h in air. The synthesized powders were character...ZnTiO3：Eu3＋ phosphors were synthesized with different concentrations of Eu3＋ doping through sol-gel method. The samples were calcined at different temperatures for 2 h in air. The synthesized powders were characterized by X-ray diffraction（XRD）, scanning electron microscopy-energy dispersive spectroscopy（SEM-EDS）, transmission electron microscopy（TEM）, Raman and photoluminescence spectroscopy. The XRD results showed that the Zn Ti O3：Eu3＋ phosphors doped with different concentrations of Eu3＋ ions calcined at 600 oC were of single phase, which indicated that the Eu3＋ ions had been successfully incorporated into the Zn Ti O3 host lattice and did not destroy the lattice structure of Zn Ti O3 host. The Raman spectrum, SEM and TEM also proved that the doping of Eu3＋ did not change the lattice structure of hexagonal Zn Ti O3 host. The photoluminescence（PL） of Eu3＋ ions with the main emission peak at 614 nm was observed to increase with Eu3＋ concentrations from 0.5 mol.% to 2.0 mol.% and decreased when the concentration was increased to 2.5 mol.%. The decrease in the PL intensity at higher Eu3＋ concentrations could be associated with concentration quenching effect. The CIE1931 chromaticity diagram（x, y） of Zn Ti O3：2.0 wt.%Eu3＋ phosphors were located in the red region（x=0.652, y=0.347）. The luminescence properties suggested that Zn Ti O3：Eu3＋ phosphors might be regarded as a potential red phosphor candidate for light emitting diodes（LEDs）.展开更多
Optical properties of hot pressed Sialon ceramics doped with different rare earth oxides（REOs） i.e. Eu2O3, Gd2O3, and Pr2O3 were investigated. The α-Sialon phase was the main phase obtained after sintering as obser...Optical properties of hot pressed Sialon ceramics doped with different rare earth oxides（REOs） i.e. Eu2O3, Gd2O3, and Pr2O3 were investigated. The α-Sialon phase was the main phase obtained after sintering as observed by X-ray diffraction（XRD）. The transparency of different samples of varying thickness measured from UV to IR region revealed that the samples were translucent in the visible region while transparent in IR region. The thin samples of 150 μm thickness had transmittance as high as 30% in the visible region. The luminescence was observed in transmittance mode to investigate the effect of sample thickness on luminescence intensity. We observed blue, yellow and red emissions in Sialon doped with Gd2O3, Eu2O3, and Pr2O3, respectively. The excitation wavelength for Gd2O3 and Pr2O3 doped samples were in UV region i.e. 280 and 270 nm, respectively, whereas, for Eu2O3 doped samples was in the blue region（460 nm）. The Eu2O3 doped Sialon having 300 μm thickness showed better white light extraction as coupled with blue LED. Moreover, the fabricated phosphor samples exhibited high hardness around 20 GPa and fracture toughness above 5 MPa·m1/2.展开更多
This paper investigates the photoluminescence properties of NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋ phosphors. NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋ powder were synthesized successfully by solid st...This paper investigates the photoluminescence properties of NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋ phosphors. NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋ powder were synthesized successfully by solid state reaction method. Phase purity was checked using X-ray powder diffractometry（XRD）. The excitation and emission spectra were recorded to elucidate the photoluminescence properties of NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋. Furthermore,fluorescence lifetime measurements were performed. The excitation spectra of NaCaTiNbO6：Pr^3＋ show a main band centered at around 357 nm.The luminescence spectra of NaCaTiNbO6：Pr^3＋ exhibit a red emission peak at 615 nm from the ^1 D2→^3 H4 transition of Pr^3＋ ions. With the introduction of the Bi^3＋ ion into NaCaTiNbO6：Pr^3＋, the luminescence intensity is enhanced nearly two times. Meanwhile,the absorption band edge of NaCaTiNbO6：Pr^3＋ is shifted from 380 to 420 nm. Thus, this study shows that the red phosphor NaCaTiNbO6：Pr^3＋ incorporated with Bi^3＋ is advantageous for light-emitting diode applications.展开更多
AlON：1.6 mol.%Er3＋, x mol.%Yb3＋（x=0, 2.6, 3.1, 3.6, 4.1, 4.6） phosphors were synthesized successfully by aluminothermic reduction and nitridation（ATRN） method and characterized by X-ray diffraction（XRD）, scan...AlON：1.6 mol.%Er3＋, x mol.%Yb3＋（x=0, 2.6, 3.1, 3.6, 4.1, 4.6） phosphors were synthesized successfully by aluminothermic reduction and nitridation（ATRN） method and characterized by X-ray diffraction（XRD）, scanning electron microscopy（FESEM） and upconversion photoluminescence（UCPL） emission spectra. Under the excitation of diode laser 980 nm, the green（556 nm） and red（655 nm） upconverted emissions were observed, attributed to the 4S3/2→4I15/2 and 4F9/2→4I15/2 transition of Er3＋respectively. The emission intensity increased with increasing Yb3＋ concentration due to the energy transfer（ET） between Yb3＋ and Er3＋. The upconverted emission reached the highest as x=3.6, and was pump-power dependent involving a two-photon process.展开更多
YbF（2.357, YbF3, Ba2 YbF7, and Ba 2 upconversion nanocrystals doped with emitter Er^3＋ ion were synthesized in the same solvent system just with changing the molar ratio of Ba^2＋ to Yb^3＋ in the precursor, which c...YbF（2.357, YbF3, Ba2 YbF7, and Ba 2 upconversion nanocrystals doped with emitter Er^3＋ ion were synthesized in the same solvent system just with changing the molar ratio of Ba^2＋ to Yb^3＋ in the precursor, which corresponed to the crystal phases of rhombohedral, orthorhombic, tetragonal, and cubic, respectively. All the samples emitted both 660 nm red light and 543/523 nm green light which originated from Er^3＋-4f^n electronic transitions ~4F（9/2-~4I（15/2 and ~4S（3/2/~2H（11/2-~4I（15/2, respectively. It was worth mentioning that YbF 3：Er^3＋, Ba2 YbF7：Er^3＋, and BaF2：Er^3＋ could emit dazzlingly bright light even under the excitation of a 980 nm CW laser with output power of 0.1 W. Upconversion emission mechanism analysis indicated that the intensity ratio of red to green light highly depended on the synergistic effect of crystal structure, concentration quenching, and particle size, but were not sensitive to crystallinity as previously reported for NaL nF4（Ln=lanthanide.展开更多
CaMoO_4：Pr^（3＋）/Yb^（3＋） powder was successfully synthesized by a facile hydrothermal method. X-ray diffraction（XRD） patterns of samples confirmed tetragonal structure and morphology and sizes were confirmed b...CaMoO_4：Pr^（3＋）/Yb^（3＋） powder was successfully synthesized by a facile hydrothermal method. X-ray diffraction（XRD） patterns of samples confirmed tetragonal structure and morphology and sizes were confirmed by scanning electron microscopy（SEM） analyses. Particles consisted of regular micro-spheres with uniform sizes, the diameter of each sphere lay in the range of 3 to 4 μm. The up-conversion photoluminescence emission and its concentration dependence were investigated under infrared excitation at 980 nm. All the UC micro-particles exhibited the typical blue, green and red emissions. Dominant blue emissions originated from ~3P_0→~3H_4 and intense red emissions originated from ~3P0→~3F_2 transitions, and they both belonged to two-photon excitation processes in CaMoO_4： Yb^（3＋）/Pr^（3＋） powder. The optimum doping concentrations of Pr^（3＋） and Yb^（3＋） for the highest UC luminescence were 0.1 mol.% and 16 mol.%, respectively. The possible up-conversion mechanisms were discussed in detail. It was found that the UC emission could be well controlled from blue to green to white color by adjusting the concentration of Pr^（3＋） ions in CaMoO_4：Pr^（3＋）/Yb^（3＋） microcrystal. So it is a candidate material for solid-state lasers, biological imaging, solar cells, and optical communications.展开更多
Biocompatible NaREF_4（RE=0.4Y＋0.4La＋0.2（Yb,Er,Tm）（molar ratio）） upconversion nanoparticles（UCNPs） with strong visible fluorescence were synthesized by a solvothermal method and subsequent surface modificatio...Biocompatible NaREF_4（RE=0.4Y＋0.4La＋0.2（Yb,Er,Tm）（molar ratio）） upconversion nanoparticles（UCNPs） with strong visible fluorescence were synthesized by a solvothermal method and subsequent surface modification. Modulated upconversion luminescence emission spectra were obtained via changing the doping. In vitro and in vivo bioimagings were carried out with shrimps. The upconversion nanoprobes with an acidic/PEG hybrid ligand could quickly capture the basic Rhodamine-B（RB） in shrimp cells and formed a close UCNPs@RB system. The residual organic dye RB in shrimps could be detected on the basis of luminescent resonance energy transfer（LRET）. It could be rapidly addressed based on LRET detection that RB residue existed in the shrimps after incubating in the aqueous solution of RB higher than 3 μg/m L for 12 h.展开更多
LiYF_4 nanocrystals with tetragonal structure were adopted as the host materials for the phosphors and scintillators owing to the low phonon energy and high optical transparency. LiYF_4：Ln^（3＋）（Ce^（3＋）,Eu^（3...LiYF_4 nanocrystals with tetragonal structure were adopted as the host materials for the phosphors and scintillators owing to the low phonon energy and high optical transparency. LiYF_4：Ln^（3＋）（Ce^（3＋）,Eu^（3＋）） nanocrystals were fabricated by solvothermal method. Under UV excitation, they could emit visible light. In order to improve the luminescence intensity, the method of co-doping LiYF_4 nanocrystals with Sc was adopted. Sc^（3＋） ions could reduce the lattice expansion caused by the doping of Ce^（3＋） or Eu^（3＋） whose ionic radius was larger than Y^（3＋）. Crystal structure of Li（Y,Sc）F_4：Ln^（3＋） kept much more stable and the luminescence intensity could be significantly enhanced when the concentration of Sc was a moderate value. Thermoluminescence was employed to analyze the electron traps in Li（Y,Sc）F_4：Ce^（3＋）. Results suggested that the suppression of the generation of electron traps with the co-doping of Sc contributed to the enhancement of luminescence intensity of LiYF_4：Ce^（3＋）.展开更多
A new series of β-Sr Ge（PO_4）_2：RE（RE=Eu^2＋,Eu^3＋,Tb^3＋） phosphors were synthesized and characterized by using X-ray powder diffraction as well as excitation, and emission spectroscopy. The results exhibited ...A new series of β-Sr Ge（PO_4）_2：RE（RE=Eu^2＋,Eu^3＋,Tb^3＋） phosphors were synthesized and characterized by using X-ray powder diffraction as well as excitation, and emission spectroscopy. The results exhibited that the singly doping Eu2＋, Tb^3＋ and Eu^3＋ of β-Sr Ge（PO_4）_2 emit strong blue, green and red light under UV irradiation, respectively. Based on the charge transfer transitions of O^2-→RE^3＋, an overlapping excitation band of the as-obtained phosphors could be found in UV region, which made β-Sr Ge（PO_4）_2：RE（RE=Eu^2＋,Eu^3＋,Tb^3＋） serve as a new series of RGB phosphors. Meanwhile, these phosphors could also be excited by 380 nm excitation simultaneously, and hence the three phosphors mixed physically could achieve the tunable hues from blue to white region by adjusting the mixed ratios.展开更多
A series of Ba5Si8O（21）：0.02Eu^2＋,0.09RE^3＋ persistent phosphors were synthesized by the solid-state reaction method.The measurement results of photoluminescence（PL）,phosphorescence and thermoluminescence（TL）...A series of Ba5Si8O（21）：0.02Eu^2＋,0.09RE^3＋ persistent phosphors were synthesized by the solid-state reaction method.The measurement results of photoluminescence（PL）,phosphorescence and thermoluminescence（TL）were analysed and discussed.The XRD results showed that samples codoped with different RE^3＋ were Ba5Si8O（21） single pure phase.Under the excitation,all samples exhibited a broad Eu^2＋ characteristic emission,and the La^3＋ co-doped sample emitted the brightest photoluminescence even though its persistent luminescence property was the worst because of the weakest electronegativity.However,Nd^3＋ electronegativity was suitable,thus after activation,the Ba5Si8O（21）：Eu^2＋,Nd^3＋ sample had the best persistent luminescence performance with the highest phosphorescence intensity and the persistent luminescence decay time beyond 8 h.The Nd^3＋ co-doped sample also had the largest thermoluminescence integral area which proved effectively it had longer persistent luminescence time.The luminescence mechanism was also proposed to study the photoluminescence and persistent luminescence process.These results showed that RE^3＋ electronegativities were distinctly important for persistent phosphors and choosing suitable electronegativity codopant was conducive to enhancing the phosphorescent performance.展开更多
The spectroscopic properties of lithium borate glasses as a function of Nd3＋ ions concentration were reported.Optical absorption spectra of these glasses showed a number of absorption bands in ultra violet and visibl...The spectroscopic properties of lithium borate glasses as a function of Nd3＋ ions concentration were reported.Optical absorption spectra of these glasses showed a number of absorption bands in ultra violet and visible region.Optical absorption edge was found to shift towards the longer wavelength（red shift） with increase in Nd2O3.Luminescence spectra revealed three major bands at 902, 1063 and 1334 nm which was due to 4F3/2→4I9/2, 11/2 ＆13/2 transitions of Nd3＋ ions.Luminescence intensity was maximum for 1 mol.% Nd2O3 and further increase in Nd2O3 resulted in luminescence quenching.The luminescence quenching behavior at higher concentration of Nd2O3 was attributed to the Nd3＋-Nd3＋ interaction in the glass matrix.An absorption and emission property of these glasses suggested that these glasses could be useful for 1.06 μm infrared laser applications.展开更多
Er3＋-Yb3＋ codoped oxy-fluoro-tungstosilicate glasses with infrared-to-visible frequency upconversion luminescence were prepared by melting quenching in air.The effects of Er3＋ doping on the optical properties of th...Er3＋-Yb3＋ codoped oxy-fluoro-tungstosilicate glasses with infrared-to-visible frequency upconversion luminescence were prepared by melting quenching in air.The effects of Er3＋ doping on the optical properties of the samples were measured by means of techniques such as optical absorption spectra and photoluminescence spectra.The results showed that intense green and red signals centered at 546 and 665 nm,corresponding to the 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3＋ by a multiphoton stepwise phonon-assisted excited-state absorption process,respectively,were simultaneously observed by exciting the samples with a diode laser operating at 980 nm at room temperature.The upconversion process was found very sensitive to Er3＋ content at a constant Yb2O3 content of 5 mol.%.With the increase of Er3＋ content from 0.5% to 1.5%,the upconversion intensity increased gradually.Further increasing of Er3＋ content to 3.0% resulted in a significant fluorescence quenching.Moreover,the possible upconversion mechanisms were discussed based on the energy-matching conditions and the quadratic dependence on excitation power.展开更多
A series of Eu^2＋,Tb^3＋-codoped Sr3 Y（PO4）3（SYP） green phosphors were synthesized by hightemperature solid-state reaction. Several techniques, such as X-ray diffraction, UV-vis spectrum,and photoluminescence spe...A series of Eu^2＋,Tb^3＋-codoped Sr3 Y（PO4）3（SYP） green phosphors were synthesized by hightemperature solid-state reaction. Several techniques, such as X-ray diffraction, UV-vis spectrum,and photoluminescence spectrum, were used to investigate the obtained phosphors. The present study investigates in detail photoluminescence excitation and emission properties, energy transfer between the two dopants, and effects of doping ions on optical band gap. SYP：0.05 Eu2＋ phosphor shows an intense and broad excitation band ranging from 220 to 400 nm and exhibits a bright green emission band with CIE chromaticity coordinates（0.189, 0.359） under 350 nm excitation. Green emission of SYP：0.03 Tb3＋ is intensified by codoping with Eu^2＋, and energy transfer mechanism between them is demonstrated to be a dipole-dipole interaction. Upon 350 nm excitation, SYP：Eu^2＋,Tb^3＋ phosphors exhibits two dominating bands peaking at 466 and 545 nm, which are assigned to 4 f^65 d^1→4 f^7 transition of Eu^2＋ ions and ~5 D4→~7 F5 transition of Tb^3＋ ions, respectively. Optimal doping concentrations of Eu^2＋ and Tb^3＋ in the SYP host are 5 mol% and 15 mol%, respectively. Results indicate that SYP：Eu^2＋,Tb^3＋ phosphors are potentially used as green-emitting phosphors for white light-emitting diodes.展开更多
文摘Rare earth luminescent materials have attracted significant attention due to their wide-ranging applications in the field of optoelectronics. This study aims to delve into the electronic structure and optical properties of rare earth luminescent materials, with the goal of uncovering their importance in luminescence mechanisms and applications. Through theoretical calculations and experimental methods, we conducted in-depth analyses on materials composed of various rare earth elements. Regarding electronic structure, we utilized computational techniques such as density functional theory to investigate the band structure, valence state distribution, and electronic density of states of rare earth luminescent materials. The results indicate that the electronic structural differences among different rare earth elements notably influence their luminescence performance, providing crucial clues for explaining the luminescence mechanism. In terms of optical properties, we systematically examined the material’s optical behaviors through fluorescence spectroscopy, absorption spectroscopy, and other experimental approaches. We found that rare earth luminescent materials exhibit distinct absorption and emission characteristics at different wavelengths, closely related to the transition processes of their electronic energy levels. Furthermore, we studied the influence of varying doping concentrations and impurities on the material’s optical properties. Experimental outcomes reveal that appropriate doping can effectively regulate the emission intensity and wavelength, offering greater possibilities for material applications. In summary, this study comprehensively analyzed the electronic structure and optical properties of rare earth luminescent materials, providing deep insights into understanding their luminescence mechanisms and potential value in optoelectronic applications. In the future, these research findings will serve as crucial references for the technological advancement in fields such as LEDs, lasers, and bioimaging.
基金Supported by the Innovation Fund of Donghua University for Doctors
文摘A novel Eu^3＋ rare earth complex, composed of 4 - hydroxybenzolate acid and 1, 10 - phenanthroline ligands was synthesized. The apparent morphology, composition, thermal stability and fluorescent property of the rare earth complex were measured by TEM, Element analysis, IR, TG and Fluorescence spectrometer. The results indicated that this rare earth complex has sphere-like morphology and its diameter was about 100 nm. The complex has good thermal stability due to the strong coordination between the Eu^3＋ ions and the ligands. Based on the composition analysis, the complex structure formula was： Eu （HOC6 H4 COI）3 （phen） ·H2O Fluorescence spectra showed that the rare earth complex emission peaks were corresponding to the transition of ^5D0→7FJ（J=0,1,2,4）,. and the highest intensity fluorescence peak was at 617 nm. The luminescent fiber was prepared by blending melt-spinning with rare earth complex and polypropylene resin. It also has a good luminescent quality, which the strongest emission peak was at 619 nm. It could be considered suitable for industrial application.
基金Funded by the National Basic Research Program of China(2011CB612202)
文摘A new type of samarium ion activated luminescent glass ceramics with main crystal phase of melilite was prepared. The effect of heat-treatment temperature on the structure of glass ceramics was investigated by X-ray diffraction analysis（XRD）, scanning electron microscope（SEM） and fluorescence spectrometer. In the Sm^3＋ doped SrO-MgO-SiO2 glass ceramic, its excitation spectra are in the wavelength range of 350-500 nm, and its excitation peaks are at 360 nm, 374 nm, 404 nm, 417 nm, and 475 nm with the host excitation peak of 404 nm, showing a strong orange-red luminescence when using 404 nm violet to excite it, and its emission peaks are at 564 nm, 600 nm and 648 nm with the host emission peak at 600 nm. The increase in the heat-treatment temperature has no infl uence on the position of the fl uorescent spectra. However, with the increase of heat-treatment temperature, the intensity of fl uorescence spectrum shows an increasing tendency. The increase in the concentration of Sm3＋ also improves the intensity of the fl uorescent spectra. In the experimental concentration range（0.05mol%-0.30mol%）, a special concentration quenching phenomenon happens.
基金Project supported by National High-Tech R&D Program of China(863 Program,2012AA030313)
文摘Polypropylene composite nonwovens containing rare-earth strontium aluminates Sr Al2O4：Eu2＋,Dy3＋ and functional additives were fabricated by the spun-bonded technique.The optical properties, morphology and mechanical properties of the samples were characterized.Results from scanning electron microscopy photographs（SEM） indicated that the surface of the fiber was destroyed by the addition of rare earth luminescent materials lightly but the thickness of the fiber was uniform.Differential scanning calorimetry results showed that pure polypropylene has the double crystallization peak at 162.3 and 165.1 °C.Studies from X-ray diffraction showed that the nonwoven prepared with the luminescent materials contained the α-monoclinic crystal and β crystalline phase.Furthermore, the afterglow properties were tested, which showed that the afterglow curve of the luminous nonwoven was similar to that of strontium aluminate, and the intensity was more intensive than luminous nonwoven at the beginning.The nonwoven fabricated with the luminescent material did not affect the crystal lattice of the polymer making the materials have potential applications in fluorescent lamps and field emission displays（FEDs）.
文摘The Pr(TTA)_3phen(C_2H_5OH)quarternary complex with 2-thenoyltrifluoro-acetone(TTA), 1,10-phenanthroline(phen)and ethanol were synthesized and characterized by single-crystal X-ray diffraction. The central Pr^(3+) ion is nine-coordinated. The infrared(IR)spectrum, diffuse reflectance(DR)spectrum and fluorescence measurements of the complex were investigated.
基金financially supported by the National Natural Science Foundation of China(Nos.52274273 and 51872269)the Key Laboratory of Testing and Tracing of Rare Earth Products for State Market Regulation(Jiangxi University of Science and Technology)(No.TTREP2022YB04)+4 种基金the Science and Technology Research Project of Hubei Provincial Department of Education(No.B2021091)Key Laboratory for New Textile Materials and Applications of Hubei Province(Wuhan Textile University)(No.FZXCL202107)the Open Project Program of High-Tech Organic Fibers Key Laboratory of Sichuan ProvinceChina and National Project Cultivation Plan of Wuhan Textile Universityaided by the graduate innovation fund project of Wuhan Textile University。
文摘As a material with good biocompatibility,hydroxyapatite(HAP)can have optical properties after doping with various rare earth ions.As a biocompatible fluorescent material,doped HAP could have broad applications in biological probes,drug delivery,optoelectronic materials,fluorescence anti-counterfeiting,and other aspects.In this paper,we put forward the preparation of HAP doped with terbium(Ⅲ)ions(Tb^(3+))by hydrothermal co-precipitation.By controlling the Tb^(3+)doping content in reaction and the reaction time,the changes in HAP's structure,morphology,and luminescence properties under different conditions were studied.When the doping amount of Tb^(3+)reached an optimal value,the dipole-quadrupole would occur and the concentration would be quenched.The control experiment showed that the optimal Tb3+content was 7.5×10^(-5)mol,which showed the best fluorescence performance.HAP,a non-luminous material,was rarely used in the field of fluorescent anti-counterfeiting and photoelectric devices.We proposed to prepare a luminescent aramid/polyphenylene sulfide(ACFs/PPS)fiber paper and a new light-emitting diode(LED)using the Tb-doped HAP phosphor.The composite sample exhibited an excellent stability and fluorescence performance,which also demonstrated a possibility of HAP applications in anticounterfeiting and photoelectric.The introduction of Tb3+dopant HAP was done to give HAP optical properties and broaden the application range of HAP.
文摘The system Al-2O-3-B-2O-3-Ce-2O-3, with Al/B ratio varying from 4.5 to 2 and Ce/(Al+B)=0.02, has been prepared at the temperature from 1 200 to 1 400℃. Relationship between luminescence and matrices in the system Al-2O-3-B-2O-3-Ce-2O-3 was investigated. It was found that some changes of the matrices occurred with Al/B ratio varying from 4.5 to 2. These results lead to a great change in luminescence properties, indicating variation of Ce-surroundings of crystal field. With the decrease of the ratio from 3 to 2, the excitation and emission peaks shift to shorter wavelengths. It was also found that a new type of rare earth luminescent materials was obtained with appropriate Al/B ratio.
基金Project supported by Natural Science Foundation of the Jiangsu Higher Education Institutions of China(12KJA430006,13KJB430024)
文摘ZnTiO3：Eu3＋ phosphors were synthesized with different concentrations of Eu3＋ doping through sol-gel method. The samples were calcined at different temperatures for 2 h in air. The synthesized powders were characterized by X-ray diffraction（XRD）, scanning electron microscopy-energy dispersive spectroscopy（SEM-EDS）, transmission electron microscopy（TEM）, Raman and photoluminescence spectroscopy. The XRD results showed that the Zn Ti O3：Eu3＋ phosphors doped with different concentrations of Eu3＋ ions calcined at 600 oC were of single phase, which indicated that the Eu3＋ ions had been successfully incorporated into the Zn Ti O3 host lattice and did not destroy the lattice structure of Zn Ti O3 host. The Raman spectrum, SEM and TEM also proved that the doping of Eu3＋ did not change the lattice structure of hexagonal Zn Ti O3 host. The photoluminescence（PL） of Eu3＋ ions with the main emission peak at 614 nm was observed to increase with Eu3＋ concentrations from 0.5 mol.% to 2.0 mol.% and decreased when the concentration was increased to 2.5 mol.%. The decrease in the PL intensity at higher Eu3＋ concentrations could be associated with concentration quenching effect. The CIE1931 chromaticity diagram（x, y） of Zn Ti O3：2.0 wt.%Eu3＋ phosphors were located in the red region（x=0.652, y=0.347）. The luminescence properties suggested that Zn Ti O3：Eu3＋ phosphors might be regarded as a potential red phosphor candidate for light emitting diodes（LEDs）.
基金supported by Global Research Laboratory(GRL)Program of the National Research Foundation of Korea(NRF)funded by Ministry of Education,Science and Technology(MEST),Republic of Korea(2010-00339)
文摘Optical properties of hot pressed Sialon ceramics doped with different rare earth oxides（REOs） i.e. Eu2O3, Gd2O3, and Pr2O3 were investigated. The α-Sialon phase was the main phase obtained after sintering as observed by X-ray diffraction（XRD）. The transparency of different samples of varying thickness measured from UV to IR region revealed that the samples were translucent in the visible region while transparent in IR region. The thin samples of 150 μm thickness had transmittance as high as 30% in the visible region. The luminescence was observed in transmittance mode to investigate the effect of sample thickness on luminescence intensity. We observed blue, yellow and red emissions in Sialon doped with Gd2O3, Eu2O3, and Pr2O3, respectively. The excitation wavelength for Gd2O3 and Pr2O3 doped samples were in UV region i.e. 280 and 270 nm, respectively, whereas, for Eu2O3 doped samples was in the blue region（460 nm）. The Eu2O3 doped Sialon having 300 μm thickness showed better white light extraction as coupled with blue LED. Moreover, the fabricated phosphor samples exhibited high hardness around 20 GPa and fracture toughness above 5 MPa·m1/2.
基金Project supported by National Natural Science Foundation of China(51362028)Nature Science Fund of Science and Technology Department of Jilin Province(20130101035JC)
文摘This paper investigates the photoluminescence properties of NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋ phosphors. NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋ powder were synthesized successfully by solid state reaction method. Phase purity was checked using X-ray powder diffractometry（XRD）. The excitation and emission spectra were recorded to elucidate the photoluminescence properties of NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋. Furthermore,fluorescence lifetime measurements were performed. The excitation spectra of NaCaTiNbO6：Pr^3＋ show a main band centered at around 357 nm.The luminescence spectra of NaCaTiNbO6：Pr^3＋ exhibit a red emission peak at 615 nm from the ^1 D2→^3 H4 transition of Pr^3＋ ions. With the introduction of the Bi^3＋ ion into NaCaTiNbO6：Pr^3＋, the luminescence intensity is enhanced nearly two times. Meanwhile,the absorption band edge of NaCaTiNbO6：Pr^3＋ is shifted from 380 to 420 nm. Thus, this study shows that the red phosphor NaCaTiNbO6：Pr^3＋ incorporated with Bi^3＋ is advantageous for light-emitting diode applications.
基金Project supported by National Natural Science Foundation of China(91022035)"One Hundred Talent Project"the Natural Science Foundation of Fujian Province(2014H0055)
文摘AlON：1.6 mol.%Er3＋, x mol.%Yb3＋（x=0, 2.6, 3.1, 3.6, 4.1, 4.6） phosphors were synthesized successfully by aluminothermic reduction and nitridation（ATRN） method and characterized by X-ray diffraction（XRD）, scanning electron microscopy（FESEM） and upconversion photoluminescence（UCPL） emission spectra. Under the excitation of diode laser 980 nm, the green（556 nm） and red（655 nm） upconverted emissions were observed, attributed to the 4S3/2→4I15/2 and 4F9/2→4I15/2 transition of Er3＋respectively. The emission intensity increased with increasing Yb3＋ concentration due to the energy transfer（ET） between Yb3＋ and Er3＋. The upconverted emission reached the highest as x=3.6, and was pump-power dependent involving a two-photon process.
基金Project supported by the National Natural Science Foundation of China(11274263,21301058,11274263)
文摘YbF（2.357, YbF3, Ba2 YbF7, and Ba 2 upconversion nanocrystals doped with emitter Er^3＋ ion were synthesized in the same solvent system just with changing the molar ratio of Ba^2＋ to Yb^3＋ in the precursor, which corresponed to the crystal phases of rhombohedral, orthorhombic, tetragonal, and cubic, respectively. All the samples emitted both 660 nm red light and 543/523 nm green light which originated from Er^3＋-4f^n electronic transitions ~4F（9/2-~4I（15/2 and ~4S（3/2/~2H（11/2-~4I（15/2, respectively. It was worth mentioning that YbF 3：Er^3＋, Ba2 YbF7：Er^3＋, and BaF2：Er^3＋ could emit dazzlingly bright light even under the excitation of a 980 nm CW laser with output power of 0.1 W. Upconversion emission mechanism analysis indicated that the intensity ratio of red to green light highly depended on the synergistic effect of crystal structure, concentration quenching, and particle size, but were not sensitive to crystallinity as previously reported for NaL nF4（Ln=lanthanide.
基金Project supported by the National Science Foundation of China(11574190)the Fundamental Research Funds for the Central Universities(GK201503024)
文摘CaMoO_4：Pr^（3＋）/Yb^（3＋） powder was successfully synthesized by a facile hydrothermal method. X-ray diffraction（XRD） patterns of samples confirmed tetragonal structure and morphology and sizes were confirmed by scanning electron microscopy（SEM） analyses. Particles consisted of regular micro-spheres with uniform sizes, the diameter of each sphere lay in the range of 3 to 4 μm. The up-conversion photoluminescence emission and its concentration dependence were investigated under infrared excitation at 980 nm. All the UC micro-particles exhibited the typical blue, green and red emissions. Dominant blue emissions originated from ~3P_0→~3H_4 and intense red emissions originated from ~3P0→~3F_2 transitions, and they both belonged to two-photon excitation processes in CaMoO_4： Yb^（3＋）/Pr^（3＋） powder. The optimum doping concentrations of Pr^（3＋） and Yb^（3＋） for the highest UC luminescence were 0.1 mol.% and 16 mol.%, respectively. The possible up-conversion mechanisms were discussed in detail. It was found that the UC emission could be well controlled from blue to green to white color by adjusting the concentration of Pr^（3＋） ions in CaMoO_4：Pr^（3＋）/Yb^（3＋） microcrystal. So it is a candidate material for solid-state lasers, biological imaging, solar cells, and optical communications.
基金Project supported by the National Natural Science Foundation of China(61376076,61674056,61675067,61575062,51275167,61377024)supported by the Scientific Research Fund of Hunan Provincial Education Department(16A072)
文摘Biocompatible NaREF_4（RE=0.4Y＋0.4La＋0.2（Yb,Er,Tm）（molar ratio）） upconversion nanoparticles（UCNPs） with strong visible fluorescence were synthesized by a solvothermal method and subsequent surface modification. Modulated upconversion luminescence emission spectra were obtained via changing the doping. In vitro and in vivo bioimagings were carried out with shrimps. The upconversion nanoprobes with an acidic/PEG hybrid ligand could quickly capture the basic Rhodamine-B（RB） in shrimp cells and formed a close UCNPs@RB system. The residual organic dye RB in shrimps could be detected on the basis of luminescent resonance energy transfer（LRET）. It could be rapidly addressed based on LRET detection that RB residue existed in the shrimps after incubating in the aqueous solution of RB higher than 3 μg/m L for 12 h.
基金supported by the National Natural Science Foundation of China(51171239)Shanghai University Innovation Program
文摘LiYF_4 nanocrystals with tetragonal structure were adopted as the host materials for the phosphors and scintillators owing to the low phonon energy and high optical transparency. LiYF_4：Ln^（3＋）（Ce^（3＋）,Eu^（3＋）） nanocrystals were fabricated by solvothermal method. Under UV excitation, they could emit visible light. In order to improve the luminescence intensity, the method of co-doping LiYF_4 nanocrystals with Sc was adopted. Sc^（3＋） ions could reduce the lattice expansion caused by the doping of Ce^（3＋） or Eu^（3＋） whose ionic radius was larger than Y^（3＋）. Crystal structure of Li（Y,Sc）F_4：Ln^（3＋） kept much more stable and the luminescence intensity could be significantly enhanced when the concentration of Sc was a moderate value. Thermoluminescence was employed to analyze the electron traps in Li（Y,Sc）F_4：Ce^（3＋）. Results suggested that the suppression of the generation of electron traps with the co-doping of Sc contributed to the enhancement of luminescence intensity of LiYF_4：Ce^（3＋）.
基金Project supported by the National Natural Science Foundation of China(21271161)the Program for New Century Excellent Talents in University(NCET-13-0530)
文摘A new series of β-Sr Ge（PO_4）_2：RE（RE=Eu^2＋,Eu^3＋,Tb^3＋） phosphors were synthesized and characterized by using X-ray powder diffraction as well as excitation, and emission spectroscopy. The results exhibited that the singly doping Eu2＋, Tb^3＋ and Eu^3＋ of β-Sr Ge（PO_4）_2 emit strong blue, green and red light under UV irradiation, respectively. Based on the charge transfer transitions of O^2-→RE^3＋, an overlapping excitation band of the as-obtained phosphors could be found in UV region, which made β-Sr Ge（PO_4）_2：RE（RE=Eu^2＋,Eu^3＋,Tb^3＋） serve as a new series of RGB phosphors. Meanwhile, these phosphors could also be excited by 380 nm excitation simultaneously, and hence the three phosphors mixed physically could achieve the tunable hues from blue to white region by adjusting the mixed ratios.
基金Project supported by the National Natural Science Foundation of China(61265004,51272097)the Foundation of Application Research of Yunnan Province,China(2011FB022)
文摘A series of Ba5Si8O（21）：0.02Eu^2＋,0.09RE^3＋ persistent phosphors were synthesized by the solid-state reaction method.The measurement results of photoluminescence（PL）,phosphorescence and thermoluminescence（TL）were analysed and discussed.The XRD results showed that samples codoped with different RE^3＋ were Ba5Si8O（21） single pure phase.Under the excitation,all samples exhibited a broad Eu^2＋ characteristic emission,and the La^3＋ co-doped sample emitted the brightest photoluminescence even though its persistent luminescence property was the worst because of the weakest electronegativity.However,Nd^3＋ electronegativity was suitable,thus after activation,the Ba5Si8O（21）：Eu^2＋,Nd^3＋ sample had the best persistent luminescence performance with the highest phosphorescence intensity and the persistent luminescence decay time beyond 8 h.The Nd^3＋ co-doped sample also had the largest thermoluminescence integral area which proved effectively it had longer persistent luminescence time.The luminescence mechanism was also proposed to study the photoluminescence and persistent luminescence process.These results showed that RE^3＋ electronegativities were distinctly important for persistent phosphors and choosing suitable electronegativity codopant was conducive to enhancing the phosphorescent performance.
文摘The spectroscopic properties of lithium borate glasses as a function of Nd3＋ ions concentration were reported.Optical absorption spectra of these glasses showed a number of absorption bands in ultra violet and visible region.Optical absorption edge was found to shift towards the longer wavelength（red shift） with increase in Nd2O3.Luminescence spectra revealed three major bands at 902, 1063 and 1334 nm which was due to 4F3/2→4I9/2, 11/2 ＆13/2 transitions of Nd3＋ ions.Luminescence intensity was maximum for 1 mol.% Nd2O3 and further increase in Nd2O3 resulted in luminescence quenching.The luminescence quenching behavior at higher concentration of Nd2O3 was attributed to the Nd3＋-Nd3＋ interaction in the glass matrix.An absorption and emission property of these glasses suggested that these glasses could be useful for 1.06 μm infrared laser applications.
基金supported by the Fundamental Research Funds for the Central Universities
文摘Er3＋-Yb3＋ codoped oxy-fluoro-tungstosilicate glasses with infrared-to-visible frequency upconversion luminescence were prepared by melting quenching in air.The effects of Er3＋ doping on the optical properties of the samples were measured by means of techniques such as optical absorption spectra and photoluminescence spectra.The results showed that intense green and red signals centered at 546 and 665 nm,corresponding to the 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3＋ by a multiphoton stepwise phonon-assisted excited-state absorption process,respectively,were simultaneously observed by exciting the samples with a diode laser operating at 980 nm at room temperature.The upconversion process was found very sensitive to Er3＋ content at a constant Yb2O3 content of 5 mol.%.With the increase of Er3＋ content from 0.5% to 1.5%,the upconversion intensity increased gradually.Further increasing of Er3＋ content to 3.0% resulted in a significant fluorescence quenching.Moreover,the possible upconversion mechanisms were discussed based on the energy-matching conditions and the quadratic dependence on excitation power.
基金Project supported by the National Natural Science Foundation of China(61664002)the Natural Science Foundation of Guangxi Province(2016GXNSFDA380036)
文摘A series of Eu^2＋,Tb^3＋-codoped Sr3 Y（PO4）3（SYP） green phosphors were synthesized by hightemperature solid-state reaction. Several techniques, such as X-ray diffraction, UV-vis spectrum,and photoluminescence spectrum, were used to investigate the obtained phosphors. The present study investigates in detail photoluminescence excitation and emission properties, energy transfer between the two dopants, and effects of doping ions on optical band gap. SYP：0.05 Eu2＋ phosphor shows an intense and broad excitation band ranging from 220 to 400 nm and exhibits a bright green emission band with CIE chromaticity coordinates（0.189, 0.359） under 350 nm excitation. Green emission of SYP：0.03 Tb3＋ is intensified by codoping with Eu^2＋, and energy transfer mechanism between them is demonstrated to be a dipole-dipole interaction. Upon 350 nm excitation, SYP：Eu^2＋,Tb^3＋ phosphors exhibits two dominating bands peaking at 466 and 545 nm, which are assigned to 4 f^65 d^1→4 f^7 transition of Eu^2＋ ions and ~5 D4→~7 F5 transition of Tb^3＋ ions, respectively. Optimal doping concentrations of Eu^2＋ and Tb^3＋ in the SYP host are 5 mol% and 15 mol%, respectively. Results indicate that SYP：Eu^2＋,Tb^3＋ phosphors are potentially used as green-emitting phosphors for white light-emitting diodes.
