Orange-red Phosphors Research Articles

Study on the structure and luminescence properties of a novel Li3Sc2(PO4)3: Eu3+ orange-red emission phosphor for wLEDs

The manufacture of high-efficiency and stable red phosphor is the key to solve the matter of high color temperature and poor color rendering of commercial white light-emitting diodes (wLEDs). In this work, a series of Li3Sc2-x(PO4)3: xEu3+ (x = 0–0.4) phosphor samples were prepared by conventional solid-phase reaction. The structure and optical properties of Li3Sc2(PO4)3: Eu3+ are investigated. When the doping amount of Eu3+ is 0.3 mol, phosphors have the highest luminescence intensity. The temperature-dependent characteristics of the prepared phosphors are studied. The combined emission intensity at 423K is 77.4% of that at 298K, showing significant thermal stability. Finally, the prepared Li3Sc2(PO4)3 phosphor package is tested in the LED device. The results of the color temperature of 5423K, as well as color rendering index (CRI) (Ra = 81.6) and color coordinate CIE (0.3343, 0.3471), are satisfactory, suggesting that this red phosphor has potential for wLEDs applications.

Synthesis and luminescent properties of Na5(La,Y) (MoO4)4: Sm3+ phosphors for solid-state lighting application

The Sm3+ and La3+ co-doped Na5Y(MoO4)4 orange-red phosphors were synthesized by solid phase method at 600 °C. The crystal structure, phase purity, thermal stability, and luminescence performance were comprehensively analyzed. Under 405 nm excitation, the phosphors emit the orange-red light because of the 4G5/2-6H5/2, 4G5/2-6H7/2, 4G5/2-6H9/2, and 4G5/2-6H11/2 transitions of Sm3+ ions. The enhancement of emission intensity with La3+ ions doping in phosphors is due to the environmental effect of the crystal field around the luminous center. When it is combined with commercial LED chips, the device emits orange-red light, and the luminescence spectrum coincides with the PR pigment absorption spectrum of the plant, indicating that the potential of Sm3+ and La3+ co-doped Na5Y(MoO4)4 phosphors in solid-state lighting application.

Highly symmetric lattice environment induced orange-red emitting of Eu3+ in a novel tungstate phosphor with broad-band ultraviolet excitation

In this work, we reported the synthesis and characteristic luminescence of an orange-red emitting phosphor NaBa10Y5W4O30: Eu3+ for ultra-violet white light emitting diodes. The phase compound, crystalline structure and morphology are analyzed. The results indicate that a heavy doping of Eu3+ (x = 50%) is realized in NaBa10Y5-5xW4O30: xEu3+ without any impurity phase. Moreover, the optical band gap is analyzed by diffuse reflectance spectroscopy and further confirmed by density function theory (DFT). Meanwhile, the as-synthesized NaBa10Y5W4O30: Eu3+ phosphor can be efficiently pumped by strong broad-band excitation around 315 nm due to the charge transfer transition from [WO6]6- groups to Eu3+. Owing to the highly symmetric lattice environment of Eu3+ in YO6 sites, a strong orange-red emission at 596 nm with color purity of 95.34% is obtained, corresponding to the 5D0→7F1 magnetic dipole transition of Eu3+ ions. The critical concentration is obtained to be x = 15%, and the quenching mechanism is discussed to be dipole–dipole interaction. Furthermore, the temperature dependent emission behavior are analyzed, and the thermal quenching mechanism are explained by the variable temperature decay curve and configuration coordination diagram. Finally, an orange-red light emitting diode lamp is fabricated based on NaBa10Y5W4O30: 15%Eu3+ phosphor and 315 nm semiconductor chip. In summary, the results indicate that NaBa10Y5W4O30: Eu3+ phosphor has the potential to be an orange-red phosphor for white light emitting diodes.

A study on structural and luminescence properties of novel orange-red emitting Sm3+ doped Sr3LiSbO6 nanorod phosphor with high color purity for W-LEDs

Being a simple synthesis technique, solid state reaction (SSR) method seldom generates 1D nanorod structured phosphors. In this article, we present a systematic study on the structural, morphological and spectroscopic properties of double perovskite type Sr3LiSbO6:Sm3+ phosphors prepared by the conventional SSR method. X-ray diffraction (XRD) analysis confirm the successful synthesis of hexagonal structured Sr(3−x)LiSbO6:xSm3+(x = 0,0.06,0.08,0.1,0.2,0.4 mol) phosphors and Fourier-Transform Infrared spectra (FTIR) revealed the molecular vibrations present in the samples. The surface morphology was confirmed by Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) analysis. The TEM images illustrate the one – dimensional nanorod structure of the phosphor with an average diameter of 35 nm and length of 350 nm. In photoluminescence (PL) spectroscopy, under an excitation of 406 nm the characteristic emissions at 564, 601, 649 and 710 nm, which correspond to the transitions from 4G5/2 to 6H5/2, 6H7/2, 6H9/2 and 6H11/2 respectively of Sm3+ were obtained with strong orange - red emission at 601 nm. The concentration quenching was observed at x = 0.1 mol and the critical distance for energy transfer between Sm3+ ions was calculated to be 14.32 Å. The energy transfer mechanism was determined to be dipole-dipole interaction. The decay analysis confirms the shorter life time of the activator ions in the microseconds (µs) range. The estimated CIE coordinates are (0.6057, 0.397) in the warm CCT region with 100 % color purity. Hence these results suggests that Sm3+ doped Sr3LiSbO6 to be a potential orange-red nanorod phosphor in the design of various photonic devices such as phosphor converted LEDs (pc- LEDs).

A novel orange-red Ba3MgTa2O9:Eu3+ phosphor synthesis and luminescence properties in WLEDs

A new orange-red phosphor Ba3MgTa2O9:xEu3+ (0.05 ≤ x ≤ 0.60) was successfully prepared through the high-temperature solid-state reaction. A study of its structure, morphology, photoluminescence and fluorescence lifetime was conducted. By exposing the phosphor to near-ultraviolet (n-UV) light, orange-red light is generated as a result of the 7F0→5D1 magnetic dipole transition. The emission intensity is maximal at a doping concentration of x = 0.4, and concentration quenching occurs at higher concentrations. At 423 K, Ba3MgTa2O9:0.4Eu3+ phosphor luminescence intensity remained at 71% in reference to that at 303 K, showing good thermal stability. The CIE coordinates of the phosphor with the optimal doping concentration at room temperature are located at (0.6008, 0.3942) with a color purity of 98.27%. A high color rendering index is achieved by the prepared WLEDs, with Ra = 93.8 and CCT = 5671 K, which are located in the white light region of CIE with the coordinates of (0.3286, 0.3487). It is shown that the prepared Ba3MgTa2O9:Eu3+ phosphor is a potential orange-red phosphor material for WLEDs.

Energy transfer in Sm3+/Eu3+ doped Li6Gd(BO3)3 orange-red phosphor

Sm3+ and Sm3+/Eu3+ doped Li6Gd(BO3)3 (LGBO) powders were prepared by solid-state reaction. The microstructure, luminescent characteristics, energy transfer and fluorescence lifetimes were studied. Gd3+ can absorb energy and transfer it to Sm3+ under 278 nm excitation, which increases the luminescent intensity of Sm3+ at 567, 611 and 649 nm. Under 405 nm excitation, the 4G5/2-6H5/2 transition belonging to Sm3+ and the 5D0-7F2 transition belonging to Eu3+ appear in the emission spectra of Sm3+/Eu3+ co-doped LGBO phosphors, glowing yellow-orange and red light, respectively. The mechanism behind the energy transfer was analyzed, and the energy transfer efficiency was calculated to be 31.2% when the Sm3+ concentration reached 4mol%. The LGBO:Sm3+/Eu3+ phosphors have prospective applications in solid-state lighting, display devices, bio-imaging, etc.

A novel reddish-orange-emitting phosphor Ca3Gd7(PO4)(SiO4)5O2: Sm3+ for white light-emitting diodes

Phosphor is the decisive material in white light-emitting diodes (WLED), affecting light quality. Silica phosphate has good stability, low cost and environmentally friendly features, so it has great application potential. In this paper, a self-activated reddish-orange phosphor Ca3Gd7(PO4)(SiO4)5O2: xSm3+ was prepared by the high-temperature solid-phase method. The phase purity of the sample was verified by X-ray diffraction (XRD). The Rietveld refinement method was used to resolve further the sample structure and the location of the substitution of rare earth ions. The photoluminescence properties were studied in detail using fluorescence spectra, temperature-dependent emission spectra and other characterization methods. The electron transition and energy transfer processes of Gd3+ in Ca3Gd7(PO4)(SiO4)5O2 were analyzed. The fluorescence decay curve of the sample was obtained, which belongs to the double exponential curve, and the decay lifetime depending on the Sm3+ doping concentration was calculated. Furthermore, a WLED device was assembled, and warm white light was obtained, with a spectrum showing characteristic red emission, proving to complement the missing red component of commercial WLEDs. These results indicate that Ca3Gd7(PO4)(SiO4)5O2: xSm3+ phosphor has great potential for application.

α-Ba2ScAlO5: Eu3+ as a promising thermally stable orange-red emission phosphor

The thermal quenching effect of phosphors restricts the practical application due to the serious energy loss. Herein, excellent thermal stability of Eu3+ emission is observed in the α-Ba2ScAlO5:xEu3+ phosphors. The compounds crystallize in the hexagonal sole-phase structure with partial replacement of Sc3+ by Eu3+. Apart from the 4f6→4f6 transitions, luminescence excitation spectra of α-Ba2ScAlO5: xEu3+ show an intense charge transfer band (CTB). Upon excitation into the CTB, the emission of Eu3+ shows normal thermal quenching with intensity at 210 °C keeping 70% of that measured at room temperature. When excited into the characteristic line at 393 nm, the emission of Eu3+ demonstrates even better thermal stability while photoluminescence intensity declines by only 5% at 210 °C compared to that at room temperature. The CTB is shown to play a role of an intermediate level to impact the energy transfer mechanism responsible for excellent thermal stability.

Photoluminescence properties and energy transfer of Sr3Sc(BO3)3: Eu3+, Bi3+ phosphors

A number of orange-red Sr3Sc(BO3)3 phosphors with Eu3+ single-doping and Eu3+, Bi3+ co-doping were successfully made using the high-temperature solid-state method. The morphology and composition of the samples were examined using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), high-angle annular dark field (HAADF), and energy dispersive spectroscopy (EDS). Excitation and emission spectroscopy were used to investigate the characteristics of photoluminescence. In this work, Bi3+ are used as sensitizer to improve the emission intensity of Eu3+. The critical (or optimum) doping concentrations of Eu3+ and Bi3+ in Sr3Sc(BO3)3 were obtained experimentally (single-doping: 15 mol.% Eu3+, co-doping: 15 mol.% Eu3+, 0.3 mol.% Bi3+) to explore the energy transfer from Bi3+ to Eu3+. Under UV (393 nm) excitation, a strong orange-red luminescence corresponding to the 5D0→7F1 transition of Eu3+ can be observed, and a clear energy transfer from Bi3+ to Eu3+ can be discovered in the co-doped Sr3Sc(BO3)3. The energy transfer mechanism, as well as the CIE coordinates and decay lifetimes of a representative sample, are also discussed. The results show that Sr3Sc(BO3)3:Eu3+, Bi3+ is an orange-red phosphor with a higher efficiency under near-UV excitation.

A new rare-earth orthoborate Ba2CdSm2(BO3)4: Synthesis, crystal structure, vibrational spectra, and luminescent properties

A new rare-earth orthoborate Ba2CdSm2(BO3)4 was prepared using the high temperature molten salt method and structurally characterized by single-crystal XRD analysis with following crystallographic data: Pna21, a ​= ​7.6621(1) Å, b ​= ​26.2866(4) Å, c ​= ​16.4563(3) Å, V ​= ​3314.47(9) Å3, and Z ​= ​12. It exhibits a complicated three-dimensional framework constructed from (Cd/Sm)On (n ​= ​7, 8, and 9) distorted polyhedra and BO3 planar triangles, with the open channels and the pockets on the wall of the channels hosting Ba2+ and Ba2+/Sm3+ cations. In addition, the phase purity, morphology, IR, Raman, XPS, UV–vis absorption spectra and luminescent properties of this compound were studied. Upon excitation at 401 ​nm, Ba2CdSm2(BO3)4 displays the orange-red emission with CIE coordinates of (0.5869, 0.4122), which is associated with the characteristic transitions from the excited state 4G5/2 to the ground state 6HJ (J ​= ​5/2, 7/2, 9/2, 11/2) of Sm3+ ion. The phosphor shows the stable luminescence at elevated temperature, and its room temperature fluorescent decay profile exhibits a biexponential shape with the average lifetime of 0.7297 ​ms. As it is expected, Ba2CdSm2(BO3)4 may be a potential orange-red phosphor under near-UV light excitation.

Novel orange-red phosphor Sr3Al2Si3O12:Eu3+ excited by ultraviolet or blue light with excellent thermal stability and color purity

It is still a challenge to develop orange-red phosphors with high performance, good thermal stability and high color purity. We successfully designed and synthesized aseries of novel orange-red phosphors Sr3-2xAl2Si3O12:xEu3+,xLi+ (0.04 ≤ x ≤ 0.18), which can be effectively excited by ultraviolet and bluelight. The fluorescence emission spectra of phosphors Sr3-2xAl2Si3O12:xEu3+,xLi+ are composed of several peaks at 500–750 nm, which belong to the electronic transition of 5D0→7FJ (J = 0,1,2,3,4) of Eu3+. Phosphor Sr2.8Al2Si3O12:0.1Eu3+,0.1Li+ has excellent thermal stability, when the temperature is as high as 418 K, the fluorescence emission intensity remains 77.81%, and the activation energy Ea = 0.2665 eV. The color coordinates of phosphors Sr3-2xAl2Si3O12:xEu3+,xLi+ are all located in the orange-red region (0.58,0.40), and the color purity is as high as 97.52%. These results show that phosphor Sr2.8Al2Si3O12:0.1Eu3+,0.1Li+ is a potential orange-red phosphor which can be effectively excited by ultraviolet light and blue light to obtain white light.

Photoluminescence properties of novel blue-light excited orange-red phosphors Sr3Al2Si3O12:Eu2+

Developing red phosphors for LEDs is highly demanded yet challenging. Herein, a novel Eu2+-activated orange-red phosphors Sr3-xAl2Si3O12:xEu2+ (SASO:xEu2+) (0 ≤ x ≤ 0.08, ∆x = 0.01) were successfully prepared by high-temperature solid-phase reaction. The phosphors all belong to the cubic crystal system, and the space group is Fm-3 m(225). Phosphors SASO:xEu2+ can be efficiently excited by wavelengths in the range of 420–500 nm and produces strong orange-red light emission at 618 nm. In phosphors SASO:xEu2+, the optimal doping concentration of Eu2+ is 0.06, and the Inokuti–Hirayama (I-H) model shows that the energy transfer between Eu2+ ions is mainly due to the dipole-dipole (d-d) interaction. The phosphors SASO:xEu2+ have excellent thermal stability, the fluorescence intensity of phosphor SASO:0.06Eu2+ at 418 K still maintains 69.57 % of the fluorescence intensity at room temperature. Phosphor SASO:0.06Eu2+ has a high luminescence quality with a color purity of 86.5 %, which exhibits bright orange-red emission under 450 nm illumination.

Sm3+ doped Ca3Y(AlO)3(BO3)4: A near-UV pumped orange-red phosphor with high thermal stability

Rare-earth-ion-activated borate phosphor is an intensive topic in the lighting field due to the thermally high stability and excellent luminescence efficiency. Herein, a sequence of borate phosphors: Ca3Y(AlO)3(BO3)4:x mol% Sm3+ were successfully prepared using a conventional solid-state method. We demonstrate that the sample is a monoclinic crystal system with the P63/m space group by analyzing the crystal structure and Rietveld refinement. In addition, the ultraviolet-visible-near-infrared (UV–VIS–NIR) spectra and the first-principles calculations reveal that the Ca3Y(AlO)3(BO3)4 host can provide an excellent band-gap environment (Eg=4.34 eV) for the luminescent center. Thereafter, the analysis of fluorescence spectra shows that the excitation spectrum consists of a series of peaks, among which the 405 nm peak formed by the 6H5/2→4F7/2 transition of Sm3+ plays a dominant role. From the perspective of the emission spectrum, the 4G5/2→6H7/2 (615 nm) transition is most significant among the four narrow emission bands appeared in the visible region. The concentration quenching occurs when the optimal doping concentration (6 mol%) of Sm3+ is exceeded, and the quenching mechanism is the dipole-dipole interaction. The temperature-dependent luminescence of the Ca3Y(AlO)3(BO3)4:6 mol% Sm3+ sample reveals that 97 % of the initial intensity is still maintained at 483 K, suggesting outstanding thermal stability. Beyond that, the orange-red chromaticity coordinate (0.602, 0.396), high color purity (80 %), and ideal correlated color temperature (1700 K) indicate that Ca3Y(AlO)3(BO3)4: Sm3+ phosphor is an excellent candidate as a red phosphor for converting tri-phosphors to white light-emitting-diodes (LEDs) lighting.

Narrow-band dazzling red-emitting (LiCaLa(MoO4)3:Eu3+) phosphor with scheelite structure for hybrid white LEDs and LiCaLa(MoO4)3:Sm3+,Eu3+-based deep-red LEDs for plant growth applications.

Presently, the preparation of dazzling narrow-band red-emitting phosphors for solid-state lighting is still a challenge. In this context, herein, a series of pure narrow-band red-emitting LiCaLa1-xEux(MoO4)3 phosphors was synthesized and characterized, and their spectroscopic properties were systematically studied. In addition, a series of orange-red-emitting LiCaLa1-ySmy(MoO4)3 phosphors with the simultaneous doping of Eu3+ was synthesized for plant growth applications. The optical studies revealed that the phosphors showed pure red emission with a full width at half maximum of ∼5 nm and 97% color purity. Alternatively, their absorption spectrum showed good absorption strength in the near UV to blue region. Non-concentration quenching behavior was observed even when the concentration of Eu3+ in the lattice was 100%. The dominant electric dipole transition in the emission spectrum indicated that the Eu3+ ion occupies a non-centrosymmetric site in the lattice. At 150 °C, the phosphor retained 88.83% of its emission intensity calculated at room temperature. Thus, it can be useful for the fabrication of LEDs. Subsequently, Eu-rich red and white LEDs (integrated with yellow phosphor) were fabricated with near-UV and blue LED chips, respectively. The fabricated hybrid white LED showed pure white emission with a CCT of 4762 K, CRI of 81%, and close CIE coordinates of (0.34, 0.33). The absolute quantum yield for the fully substituted LiCaEu(MoO4)3 composition was calculated to be 44.50% upon excitation at 395 nm. To utilize LED light for plant growth applications, efforts were made to synthesize orange-red (Sm3+) and deep-red (Sm3+, Eu3+) phosphors and utilize the simultaneously doped phosphor for the fabrication of deep-red LEDs. The spectral lines well-matched the spectrum of phytochrome (Pr). Thus, the phosphor in the present study is a potential candidate as a red and deep-red phosphor for the fabrication of hybrid white LEDs and deep-red LEDs (for plant growth purposes), respectively.

Dual-strategy of Eu2+ sensitization and Ca2+ substitution improves the luminescence properties of phosphor Sr2La8(SiO4)6O2:Eu

A series of novel orange-red phosphors Sr 1.9- x Ca x La 8 (SiO 4 ) 6 O 2 :0.1Eu (2+,3+) (0≤ x ≤ 1.9, Δ x= 0.3) were successfully prepared via high-temperature solid-state reaction. The crystal structure, fluorescence spectral characteristics, thermal stability, fluorescence lifetime, morphological characteristics and Eu valence state of the phosphor were systematically studied. The successful introduction of Eu 2+ broadened the excitation spectrum of Sr 1.9- x Ca x La 8 (SiO 4 ) 6 O 2 :0.1Eu (2+,3+) by more than 100 nm and increased the fluorescence intensity by 200%, realizing the energy transfer between Eu 2+ and Eu 3+ . The fluorescence intensity of Sr 0.4 Ca 1.5 La 8 (SiO 4 ) 6 O 2 :0.1Eu (2+,3+) is increased by 551% through the Ca 2+ substitution strategy, and the Ca 2+ enters the matrix lattice, which promotes the reduction of Eu 3+ to Eu 2+ and improves the energy transfer efficiency. The emission intensity of Sr 0.4 Ca 1.5 La 8 (SiO 4 ) 6 O 2 :0.1Eu (2+,3+) remained at 70.29% at 418 K. The color coordinates of Sr 1.9- x Ca x La 8 (SO 4 ) 6 O 2 :0.1Eu (2+,3+) are all located in the orange-red region, the color coordinates are about (0.59, 0.40), and the color temperature are about 2100 K. Therefore, the excellent optical properties of this series of phosphors make them have potential practical value in the LED field.

Efficient and zero thermal quenching Sm3+-activated Li2LaTiTaO7 phosphor for white LEDs.

In this work, we prepared a new orange-red phosphor Li2La1-xTiTaO7:xSm3+ (abbreviated as LLTT:Sm3+) for white light-emitting diodes (w-LEDs). Its crystal structure, microstructure, photoluminescence characteristics, luminescence lifetime and thermal quenching properties were studied in depth. The LLTT:Sm3+ phosphor shows four intense emission peaks at 563, 597, 643, and 706 nm when excited at 407 nm. Thermal quenching is caused by the dipole-quadrupole (d-q) interaction of Sm3+ ions, and the optimum doping concentration of Sm3+ is x = 0.05. Meanwhile, the LLTT:0.05Sm3+ phosphor has a high overall quantum yield (QY = 59.65%) and almost no thermal quenching. The emission intensity at 423 K is 101.5% of the initial value at 298 K, while the CIE chromaticity coordinates barely change as the temperature rises. The fabricated white LED device exhibits excellent CRI and CCT values of 90.4 and 5043 K, respectively. These findings demonstrate that the LLTT:Sm3+ phosphor has promise in w-LED applications.

Preparation and luminescence properties of Ba3P4O13:Sm3+ orange-red phosphors with high thermal stability

In this work, a series of Ba3P4O13:Sm3+ phosphors are prepared via calcining the precursor synthesized by a chemical co-precipitation method, meanwhile, the phase and fluorescence properties are characterized as required. The results demonstrate that the phosphors emit orange-red light with several emission peaks centering at 564 nm, 600 nm and 648 nm under ultraviolet (UV) excitation, which originate from the transition of 4G5/2 to 6H5/2 (or 6H7/2,6H9/2) energy level in Sm3+. Among them, Ba2.98P4O13:0.02Sm3+ phosphor exhibit the strongest emission intensity, and then concentration quenching occurs due to the d-d interaction once the concentration of Sm3+ ions exceeded 0.02. Even so, the color coordinates of all BaP4O13:Sm3+ samples are calculated to be close to (0.58, 0.41), implying a high color purity. Significantly, the charge compensation of alkali metal ions, especially for K+ ion, enhances the emission intensity, thermal stability and fluorescence lifetime of the phosphors remarkably, even zero thermal quenching is observed in the range of 25–250 °C.

Synthesis and photoluminescence properties of perovskite-structure Ba0.5Sr0.5TiO3: Sm3+ phosphors

Abstract Rare-earth ions doped luminescent materials have excellent optical properties and low energy consumption, which are widely used in optoelectronic devices. In this work, Sm3+-doped Ba0.5Sr0.5TiO3 perovskite phosphors were prepared by a convenient high-temperature solid-reaction method. A strong orange-red luminescence appeared at 600 nm, corresponding to the energy-level transition of 6H5/2 → 4F7/2. The optimal concentration of Ba0.5Sr0.5−x TiO3: xSm3+ was determined to be around x = 0.08. The forbidden band width and the fluorescence lifetime of Ba0.5Sr0.5TiO3: Sm3+ are 3.15 eV and 2.7 μs, respectively. The CIE coordinates are (0.509, 0.476). The as-prepared orange-red perovskite phosphors are expected to be used in white light–emitting diode (LED) devices.

Preparation and photoluminescence performance of BaMoO4:Sm3+ orange–red phosphor

In the present paper, orange–red BaMoO4:Sm3+ phosphor was synthesized by high-temperature solid-phase method. The morphology, elemental composition, crystal structure, photoluminescence performance, and charge compensation mechanism of BaMoO4:Sm3+ were investigated. Results indicated that the BaMoO4:Sm3+ phosphor particles were spherical-like in shape with approximate particle size of 2 μm and contained Ba, Mo, O, and Sm elements. The Rietveld-refinement of X-ray diffraction profile of BaMoO4:Sm3+ was consistent with a tetragonal lattice. Under 404 nm excitation of light, BaMoO4:Sm3+ phosphor showed the strongest emission peak at 649 nm and emitted an orange–red light. When the orange–red phosphor was packaged with a 395 nm UV chip and tested, the color coordinates were (0.3109, 0.3626) under a current of 60 mA, the color rendering index Ra = 81.5, and the color temperature was 6385 K. These results indicated that BaMoO4:Sm3+ red phosphor is suitable as a red light component in WLEDs and has potential practical applications.

Preparation and characterization of a new orange-red phosphor Ba2LaTaO6:Eu3+ with abnormal thermal quenching

Herein, double-perovskite Ba2LaTaO6 Eu-doped orange-red phosphors were successfully synthesized using a high-temperature solid-phase method. The phosphor phase purity was investigated using X-ray diffraction and microscopic morphology analyses. Their luminescence properties were investigated using absorption, emission, excitation, and temperature-dependent spectra. The transition mechanism mainly involves a magnetic–dipole transition with an energy transfer mode featuring multipole–multipole interactions, and concentration quenching is achieved via dipole–dipole interactions. In addition, the intensity of the temperature-dependent spectrum increases abnormally between 298 and 373 K, with the luminous intensity at 373 K increasing to 110% of that observed at room temperature. This phenomenon can be attributed to lattice defects in Ba2LaTaO6:Eu3+, and the phosphor luminous intensity at 473 K remains at 80.62% of that at room temperature. In addition, white-light-emitting diode devices based on this novel Ba2LaTaO6:0.35Eu3+ phosphor were fabricated to evaluate the potential applications of the as-prepared phosphor.