Phosphor For Solid-state Lighting Research Articles

Unusual Tm3+ sensitization-induced white-emitting and thermostable improvement in Ba2Y2Ge4O13:Dy3+ phosphor for solid-state lighting and optical thermometry

Unusual Tm3+ sensitization-induced white-emitting and thermostable improvement in Ba2Y2Ge4O13:Dy3+ phosphor for solid-state lighting and optical thermometry

Low-temperature synthesis and luminescence properties of blue-emitting β-SiAlON:Eu2+ phosphor using melamine as a self-propagating raw material

Sialons are widely recognized for their rigid lattice structure, high visible light transmittance, and excellent thermal stability, making them suitable matrix materials for activators. In this paper, we successfully prepared β-sialon phosphors, β-Si6-zAlzOzN8-z:Eu2+ (β-SiAlON:Eu2+), using an organic precursor method at a low synthesis temperature for the first time. X-ray diffraction analysis and Rietveld refinement confirm the β-SiAlON:Eu2+ phosphor possesses a hexagonal structure with a P63 space group. Under 320 nm excitation, β-SiAlON:Eu2+ phosphor exhibits a blue emission band centered at 415 nm due to the 5d → 4 f electron transition of Eu2+, which differs significantly from other β-SiAlON:Eu2+ phosphors with green emission. It is interesting that excessive Eu2+ activators make β-SiAlON:Eu2+ phosphor possess a green emission band centered at 510 nm. Therefore, the light-emitting color of β-SiAlON:Eu2+ phosphor shifts from the blue to the green with the increase of Eu2+ concentration. Furthermore, the activation energy of β-SiAlON:0.02Eu2+ sample is calculated to be about 0.2527 eV, which confirms β-SiAlON:Eu2+ phosphor has good thermal stability. The article presents a low-temperature and cost-effective synthesis method for preparing sialons, as well as a novel blue β-SiAlON phosphor for solid-state lighting.

Structural and photoluminescence properties of SrNb2O6: RE3+ (RE = Sm, Tb) phosphors for solid state lighting

The phosphors for pc-LEDs have high thermal stability requirements due to the high operating temperature of LEDs. In addition, there are many phosphors based on SrNb2O6, but no one has studied Sm3+ or Tb3+ as the luminescent center of SrNb2O6 host. Therefore, two new phosphors based on SrNb2O6 host are proposed in this work. One is an orange phosphor with negative thermal quenching phenomenon using Sm3+ as the luminescent center, and the other is a green phosphor with Tb3+ as the luminescent center. In this work, a series of SrNb2O6:Sm3+ and SrNb2O6:Tb3+ phosphors were prepared by the solid-state reaction method. The structure, morphology, chemical composition, absorption properties and luminescence properties of Sm3+ and Tb3+ doped SrNb2O6 samples were studied. Under 405 nm excitation, the SrNb2O6:Sm3+ samples exhibit the 4f-4f transition of Sm3+ with the strongest emission intensity at 607 nm, the emission intensity of SrNb2O6:0.03Sm3+ phosphor at 150 °C remains at 100.56% of its room temperature value and the chromaticity coordinates are located in the orange region, with a color purity of 88.19%. Under 307 nm excitation, the SrNb2O6:Tb3+ samples exhibit the 4f-4f transition of Tb3+ with the strongest emission intensity at 544 nm, the emission intensity of SrNb2O6:0.09Tb3+ phosphor at 150 °C remains at 7.68% of its room temperature value and the chromaticity coordinates are located in the green region with a color purity of 74.29%. Additionally, Na+ is introduced as a charge compensator in the Sm3+ or Tb3+ doped phosphors, which enhances their luminescence intensity. These results indicate that the two phosphors synthesized in this work have the prospect of application in the field of solid-state lighting.

Green-Emitting Perovskite BaTiO3:Ho3+ Phosphors for Solid-State Lighting

Green-Emitting Perovskite BaTiO3:Ho3+ Phosphors for Solid-State Lighting

Green Emission in Thermally Stable Er3+ Doped Lead-Free Perovskite Phosphor for Solid-State Lighting and Optical Thermometry Applications

Green Emission in Thermally Stable Er³⁺ Doped Lead-Free Perovskite Phosphor for Solid-State Lighting and Optical Thermometry Applications

Advancements of Lanthanide-doped Phosphors in Solid-state Lighting Applications

Abstract: The challenge of energy conversion and enhancement has been a problem in the world of lighting technologies as the population and global industrialization grow rapidly. Solid-state lighting (SSL) has proven to be a better alternative in the illumination industry because of its environmentally friendly and high energy efficiency. Lanthanide-doped phosphors have gained global attention in SSL because they have versatile applications with enhanced overall performance and luminescence. This review delves into the advancement in lanthanide-doped phosphors for Solid-state lighting (SSL) applications. It discusses the in-depth analysis of how to tailor the crystal lattice design, optimize the host material for emission efficiency, and minimize the non-radiative pathways. This paper further discusses the lanthanide-doped phosphor composition, strategies to obtain desired emission spectra, and enhanced color rendering index with the Energy transfer mechanism and the synthesis techniques. This review also addresses 3 processes for expanding the light spectrum, current challenges, future directions, and emerging trends present in the lanthanide-doped phosphor in Solid-state lighting (SSL) applications.

Studies on structural, photo and thermoluminescence properties of Sm3+ activated Ca3MgSi2O8 phosphors for solid-state lighting

Studies on structural, photo and thermoluminescence properties of Sm3+ activated Ca3MgSi2O8 phosphors for solid-state lighting

Effect of Tb3+ and Ce3+ Co-doping on the Structure and Photoluminescence Properties of Hexagonal Boron Nitride Phosphors.

In the paper, we have successfully prepared hexagonal boron nitride (h-BN:Tb3+, Ce3+) phosphors with melamine as the nitrogen source. The X-ray powder diffraction patterns confirm that the sample possesses a hexagonal crystal structure within the P m2 space group. It is interesting that the co-doping combination of Tb3+ and Ce3+ can markedly enhance the threshold concentration of doped activators within the limited solid solution of h-BN phosphors. Under 302nm excitation, the h-BN:Ce3+ phosphors exhibit broadband blue light emission at 406nm. In h-BN:Tb3+, Ce3+ phosphors, the co-doping of Ce3+ not only ensures high phase purity but also results in strong green light emission. The energy transfer efficiency from Ce3+ to Tb3+ is about 55%. The fluorescence lifetime increases with the increase of Ce3+ and Tb3+ concentration, and the fluorescence lifetime of h-BN:0.025Tb3+, 0.05Ce3+ phosphor reached 2.087ms. Additionally, the h-BN:0.025Tb3+, 0.05Ce3+ phosphor exhibits excellent thermal performance with an activation energy value of 0.2825eV. Moreover, the photoluminescence quantum yield of the sample exceeds 52%. Therefore, the h-BN:Tb3+, Ce3+ samples can be used as green phosphors for solid state lighting and fluorescent labeling.

Synthesis and photoluminescence study of Sm3+-activated KBaY(BO3)2 phosphor for solid-state lighting

Synthesis and photoluminescence study of Sm3+-activated KBaY(BO3)2 phosphor for solid-state lighting

SrNb2O6: Dy3+: a single phase warm white light emitting phosphor for solid-state lighting

SrNb2O6: Dy3+: a single phase warm white light emitting phosphor for solid-state lighting

Ho3+ -doped BaGd2 ZnO5 green-emitting phosphor for solid-state lighting: synthesis, characterization, and photoluminescence properties.

In this work, we present the synthesis of a green-emitting series of BaGd2 ZnO5 :xHo3+ (0.5-3mol%) phosphors using a high-temperature solid-state reaction method. Phase purity and crystal structure information were evaluated through X-ray powder diffraction patterns. Optical properties were examined through diffuse reflectance spectra, revealing that the prepared phosphor exhibited a band gap of 4.65 eV. The effect of Ho3+ doping on the morphology and ion distribution on the surface was assessed using scanning electron microscopy and time-of-flight secondary ion mass spectrometry techniques, respectively. The excitation spectra of the synthesized phosphor exhibited a charge transfer band and strong absorption transitions. The emission spectra displayed typical holmium emission characteristics, featuring a strong green emission band associated with f-f transitions from 5 F4 + 2 S2 → 5 I8 . Decay dynamics of the synthesized phosphor exhibited a single-exponential decay pattern, with lifetimes ranging from 0.103 to 0.053 ms. The intrinsic radiative lifetime, calculated through Auzel's fitting was determined to be 0.14 ms. Using the emission spectra, colorimetric behaviour was analyzed, revealing that the Commission Internationale de l'éclairage (CIE) coordinates exclusively lay within the green region at (0.285, 0.705), with an impressive colour purity of 99.6%. Given these marked properties, the synthesized phosphor exhibits great potential for a wide range of green-emitting applications, including displays, white light-emitting diodes, and security signage.

Preparation and photoluminescence properties of Ba2La8(SiO4)6O2:Eu3+ red phosphor for solid-state lighting and horticulture

In this study, the Ba2La8(SiO4)6O2: xEu3+ red phosphors were prepared by high temperature solid phase method. The phase structure, luminescence characteristics, thermal stability and color coordinates of the samples were analyzed. The results show that the Ba2La8(SiO4)6O2: xEu3+ red phosphors can be excited by ultraviolet or blue light, Under the excitation of 394 nm, the 5D0-7FJ (J = 0,1,2,3,4) transition emission of Eu3+ was observed in the range of 500–750 nm, and the strongest emission peak was located at 703 nm (5D0-7F4), the optimal doping concentration of Eu3+ is 12 %, and the mechanism of concentration quenching is attributed to the electric quadrupole–quadrupole interaction. The internal quantum efficiency (IQE) of phosphor is 23.82 %. The samples have a high activation energy (0.3193 eV) and good thermal stability in the temperature range of 300 K to 575 K, the color coordinates of all samples are located in the red luminous region. The deep red strong emission peak of Ba2La8(SiO4)6O2: xEu3+ is located at 703 nm, which is consistent with the absorption band of plant photochrome (PFR). The above results indicate that Eu3+-doped Ba2La8(SiO4)6O2 phosphor have potential applications in the field of white light LEDs and plant growth lighting.

Synthesis and tunable photoluminescence properties of Er3+/Eu3+ co-doped Na5La(MoO4)4 phosphors

The tunable emission characteristics of Er3+ doped and Er3+/Eu3+ co-doped Na5La(MoO4)4 phosphors prepared via high-temperature solid phase method were investigated. The microstructure of the modified phosphor was studied by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy, and its luminescence properties were analyzed by photoluminescence excitation and photoluminescence spectra. The energy transfer mechanism of Er3+ ions to Eu3+ ions was investigated by changing the concentration of Eu3+ ions to induce the spectral changes, and the photoluminescence decay lifetime was measured to validate the findings. Notably, under excitation at 380 nm, the co-doped phosphors exhibited tunable emission ranging from green to orange-red. Furthermore, Na5La(MoO4)4:0.04Er3+/0.04Eu3+ phosphor, when combined with a 380 nm chip, achieved desired warm white light emission. These promising results underscore the potential application of Na5La(MoO4)4:0.04Er3+/0.04Eu3+ phosphor in solid-state lighting.

GPT-Assisted Learning of Structure-Property Relationships by Graph Neural Networks: Application to Rare-Earth-Doped Phosphors.

Two challenges facing machine learning tasks in materials science are data set construction and descriptor design. Graph neural networks circumvent the need for empirical descriptors by encoding geometric information in graphs. Large language models have shown promise for database construction via text extraction. Here, we apply OpenAI's Generative Pre-trained Transformer 4 (GPT-4) and the Crystal Graph Convolutional Neural Network (CGCNN) to the problem of discovering rare-earth-doped phosphors for solid-state lighting. We used GPT-4 to datamine the chemical formulas and emission wavelengths of 264 Eu2+-doped phosphors from 274 articles. A CGCNN model was trained on the acquired data set, achieving a test R2 of 0.77. Using this model, we predicted the emission wavelengths of over 40 000 inorganic materials. We also used transfer learning to fine-tune a bandgap-predicting CGCNN model for emission wavelength prediction. The workflow requires minimal human supervision and is generalizable to other fields.

Study of morphological, elemental, optical and excitation wavelength dependent red photoluminescence in Eu3+ doped Li2SrSiO4 for solid state lighting

A comprehensive investigation of Eu3+ doped Li2SrSiO4 phosphors synthesized via the solid-state reaction method was conducted. XRD confirmed the crystalline phase and SEM along with and its 3D projection's observations confirmed that the phosphor particles were in the micro meter size range, indicating their suitability for applications in primary phosphor-converted LEDs. FTIR spectroscopy elucidated vibrational characteristics, while TGA, EDX and XPS analysed thermal stability, elemental composition and valence states respectively. Doping-induced band gap increase was attributed to the Moss-Burstein effect. Photoluminescence excitation studies revealed enhanced absorption at 394 nm compared to the charge transfer transition band (CTB) at 254 nm, aligning with industry-standard near-ultraviolet chips. XPS suggested two distinct Eu3+ sites in the LSS crystal, corroborated by excitation wavelength-dependent PL emission. As a result of excitation wavelengths, the magnetic-dipole transition (5D0 → 7F1) at 592 nm, the electric-dipole transition (5D0 → 7F2) at 615 nm and the induced electric-dipole transition ((5D0 → 7F3,4) at 650 and 700 nm arose. Additionally, the phosphor gave an improved conversion efficiency at 2% Eu doping. Low synthesis temperature, micro-sized particles, thermal stable, short lifetime, excitation bands at near UV to blue region, colour tunability, lower CCT, LER and similar CIE to available red phosphors are the key factors for the Li2SrSiO4:Eu3+ proving reliable red phosphor for solid state lighting.

A thermally stable lithium yttrium phosphate phosphor for solid-state lighting

In this work, trivalent dysprosium was incorporated with lithium yttrium phosphate LiY5P2O13 (LYP), obtaining a yellow-emitting material. The crystallographic sites of introduced Dy3+ activators are determined through the comprehensive analysis of the XRD investigation, DFT computation, and experimental luminescence spectra. Under 353 nm excitation, the LYP:Dy3+ phosphor shows bright yellow emission owing to dominant 4F9/2 → 6H13/2 transition (577 nm) of Dy3+. The luminescence quenching occurs when the Dy3+ content exceeds 0.07 mol, originating from the dipole–dipole interaction. Furthermore, the excellent thermal stability behavior (84 % at 423 K) and good resistance to color shifting (0.00634 at 473 K) for title phosphor are manifested by temperature-dependent investigation. Eventually, the w-LED fabricated with LYP:0.07Dy3+ and commercial materials exhibits stable white-emitting output (0.3595, 0.3179) with high Ra (85) and low CCT (4203 K). All the study demonstrates that the LYP:Dy3+ material is a perspective candidate in solid-state illustration field.

Photoluminescence properties of CaMgB2O5: RE3+ (RE = Dy, Eu, Sm) environmental friendly phosphor for solid state lighting

Photoluminescence properties of CaMgB2O5: RE3+ (RE = Dy, Eu, Sm) environmental friendly phosphor for solid state lighting

High-quality reddish-orange-emitting Sr6Y2Al4O15:Eu3+ phosphors for solid-state lighting and anti-counterfeiting applications

The reddish-orange emitting Sr6Y2Al4O15:Eu3+ phosphors were synthesized via a high-temperature solid-state reaction technique, and their luminescent properties were systematically studied. The dominant emission peak assigned to the electric dipole transition (5D0 → 7F2) was recorded at 612 nm owing to the non-inversion symmetry of the substituted sites of Eu3+ ions under the excitation of charge transfer band (∼261 nm). The emission of Sr6Y2Al4O15:Eu3+ revealed a Commission Internationale de l'Eclairage (CIE) chromaticity coordinate of (0.571, 0.368) and a color purity of 93.6 %. The thermal stability and photoluminescence quantum yield (PLQY) of Sr6Y2Al4O15: Eu3+ were analyzed, exhibiting a high thermal stability of 88.24 % at 423K and a good external PLQY of 36.24 %. Furthermore, the solid-state lighting (SSL) and flexible anti-counterfeiting applications of Sr6Y2Al4O15:Eu3+ were demonstrated. The red light-emitting diode (LED) was packaged with ∼260 nm ultraviolet LED chip, representing a CIE chromaticity coordinate of (0.5955, 0.3592) and a color purity of 86.53 %. The flexible anti-counterfeiting film was fabricated with polydimethylsiloxane polymer, and it showed tunable emission under different excitations. Moreover, the anti-counterfeiting ink was prepared and printed on various substrates. Consequently, the reddish-orange emitting Sr6Y2Al4O15: Eu3+ phosphors with high color purity, good thermal stability, and high quantum efficiency were introduced and potentially used in SSL and flexible anti-counterfeiting applications.

Color tunability and NIR luminescence in Cr3+/Li+ co-doped ZnGa2O4 phosphor for solid state lighting and NIR LEDs

In this work, we report the color tunable photoluminescence in the Cr3+/Li+ doped and co-doped ZnGa2O4 (ZGO) phosphors synthesized by solid state reaction method. The phase and surface morphology of ZGO phosphor were examined by XRD and SEM measurements, respectively. The EDS spectra revealed the presence of Zn, Ga, Cr and O elements in the phosphor. The vibrational structure of the phosphor materials has been analyzed by FTIR measurements. The Cr3+ doped phosphor shows electronic absorption bands at 302, 408 and 544 nm alongwith the host CTB at 260 nm. The optical band gap of the phosphor decreases via doping of Cr3+ and Cr3+/Li+ ions. The ZGO is a self-activated host and emits broad blue emission with maximum at 434 nm upon excitation at 260 nm. The Cr3+ doped phosphors show emission bands due to spin-allowed as well as spin-forbidden transitions due to Cr3+ ion in the blue, green and NIR regions on excitation with 260, 302, 408 and 544 nm wavelengths. The emission intensity is optimum for 0.5 mol% concentration of Cr3+ ion. The emission intensity of Cr3+ doped ZGO phosphor increases via doping of Li+ ion. The color tunability has been observed in the phosphor upon 260 and 302 nm excitations. The lifetimes of 4T2 (4F) and 2E states of Cr3+ ion have been measured and it is found that it decreases with increasing concentrations of Cr3+ and Cr3+/Li+ ions. The Cr3+/Li+ doped and co-doped ZGO phosphors may be suitable candidates for display devices, solid state lighting and NIR LEDs.

Structural and photoluminescence properties of europium (III)-activated lithium meta-silicate phosphors for solid-state lighting

Structural and photoluminescence properties of europium (III)-activated lithium meta-silicate phosphors for solid-state lighting