Orange-red Light Research Articles

Novel Sm3+ doped YCa4O(BO3)3 phosphors: Structural and, low and room temperature luminescent insights

Inorganic phosphors, known for their ability to capture energy from various sources and emit visible light, have become essential in the development of advanced lighting and display technologies. This study explores YCa4O(BO3)3 (YCOB) as a potential host material for phosphors, focusing on the luminescent properties of YCOB phosphors doped with Sm3+ ions. The successful integration of Sm3+ ions into the YCOB host lattice is confirmed through structural characterization using X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Energy-Dispersive X-ray Spectroscopy (EDS). Photoluminescence (PL) studies reveal distinct emission spectra with Stark energy level splitting, indicating a cooperative effect between Y3+ and Sm3+ ions. Concentration quenching, mainly attributed to dipole-dipole (d-q) interactions, is observed at higher Sm3+ concentrations. Temperature-dependent PL measurements demonstrate thermal quenching at lower temperatures and increased emission intensity with higher laser power. Thermal quenching is explained by reduced lattice vibrations and electron-phonon interactions, leading to decreased radiative recombination of charge carriers. The CIE chromaticity data position the samples in the orange-red region, emitting vibrant orange-red light. This comprehensive investigation provides insights into the synthesis and luminescent properties of YCOB:Sm3+ phosphors, highlighting their potential applications in luminescent devices.

Synthesis and optoelectronic aspects of orange-red light emitting Sm3+ doped vanadate nanomaterials for pc-WLEDs

Synthesis and optoelectronic aspects of orange-red light emitting Sm3+ doped vanadate nanomaterials for pc-WLEDs

Multifunctional Characteristics of BCTH:0.5% Sm3+ Ceramics Prepared via Hydrothermal Method and Powder Injection Molding

Briefly, 0.005-mol Sm3+-doped (Ba0.85Ca0.15)(Ti0.9Hf0.1)O3 ([(Ba0.85Ca0.15)0.995Sm0.005](Ti0.9Hf0.1)O3, BCTH:0.005Sm3+) lead-free ceramics were prepared via hydrothermal method and powder injection molding using paraffin and oleic acid as binders, and the effects of preparation method and sintering conditions on microstructure, dielectric behavior and optical properties were investigated. XRD Rietveld refinement reveals the coexistence of orthogonal, rhombohedral and tetragonal phases, in which the crystal structure and phase fraction are influenced greatly by sintering temperature and holding time. The ceramics present enhanced relaxor behavior and frequency dispersion phenomenon as compared with those prepared by the solid-state sintering method, and the diffusive index γ value is within 1.421–1.673. The transition mechanism and luminescence performance of BCTH:0.005 Sm3+ were analyzed by Blasse formula, photoluminescence spectrum and fluorescence lifetimes, where emission peaks show slight blueshift, fluorescence decay lifetime becomes shorter, electric multipole interaction dominates the energy transfer mechanism, and the down-conversion luminescence is one-photon absorption process. The CIE chromaticity color coordinate (0.4746, 0.5048), correlated color temperature 3134 K and color purity 93.58% are achieved, which reveals that the BCTH:0.005 Sm3+ ceramics express high quality yellow emission rather than orange-red light of the hydrothermal method synthesized nano-powder, and have potential application in optical field.

Fabrication of highly flexible luminescent films, hydro gels and anti-counterfeiting applications of La2MoO6:Sm3+ phosphors

Fabrication of versatile luminescent materials with remarkable quantum yield holds significant importance across various applications. In this context, a series of (1–11 mol %) Sm3+ activated La2MoO6 nanophosphors (LMO:Sm3+ NPs) has been developed. These nanophosphors, denoted as LMO:Sm3+ NPs, serve as a multifunctional platform with applications spanning white LED technology, flexible displays, hydro-gels, and anti-counterfeiting (AC) measures. These phosphors emit a vibrant orange-red light at 601 nm when excited at 402 nm owing to the Sm3+ ions 4G5/2 → 6H7/2 transition, achieving a high quantum yield of 66.2 %. The optimal doping concentration of Sm3+ ions in the LMO host material is identified as 5 mol %, with concentration quenching primarily attributed to electric multi-polar interaction. Remarkably, the newly fabricated LMO:Sm3+ phosphors exhibit a correlated color temperature (CCT) of 2064 K and maintain excellent color stability. Moreover, a transparent AC film is created using the optimized phosphor and Polydimethylsiloxane (PDMS), offering effective AC capabilities through their orange-red emission when exposed to 365 nm UV light. Notably, these phosphors exhibit sustainability, exceptional flexibility, and foldability, expanding their potential applications in the field of AC. These results underscore the potential of LMO:Sm3+ NPs as highly efficient luminescent platforms, catering to a wide range of applications, including white LED's, flexible display devices, hydro-gels, and AC solutions.

Exploring luminescent color tunability and efficient energy transfer mechanism of a single-phased hexagonal nanophosphor for white light emitting diodes (WLEDs) application

Nowadays, NUV-triggered phosphor-converted white light-emitting diodes (pc-WLEDs) have gained prominence as substantial alternatives to conventional incandescent and fluorescent lamps as a source of illumination. In this study, we have successfully developed a Tm3+ codoped La2O3:Sm3+ nanophosphor and investigated its potential suitability for application in white light-emitting diodes (WLEDs). X-ray diffraction (XRD) analysis was conducted to examine the phase impurity and structural characteristics of the synthesized nanophosphor. The analysis confirmed the formation of a single-phase La2O3 nanophosphor with a hexagonal crystal structure. The FT-IR spectrum of the synthesized nanophosphor exhibited distinct peaks associated with the vibrational frequencies of La-O bonds. The peaks observed in the fingerprint region of the spectrum, indicate the presence of La-O atoms in the nanophosphor. However, the HR-TEM analysis confirmed that the prepared nanophosphor had a polycrystalline nature and the observed particle sizes lay within the nanoscale range. The incorporation of Tm3+ ions into the host matrix led to a reduction in the optical band gap, leading to enhanced emission intensity. The photoluminescence (PL) study reveals that the Tm3+ ion exhibited blue emission upon excitation at 360 nm, whereas the Sm3+ ion emits reddish-orange light when excited at 379 nm and 408 nm, respectively. However, under 325 nm excitation, the nanophosphor exhibited a white emission color that resulted from the blending of colors emitted by both Tm3+ and Sm3+ ions. This unique finding suggests that this nanophosphor has the potential to generate white light specifically under this particular excitation wavelength. The efficient energy transfer between Tm3+ and Sm3+ ions was attributed to the electric multipolar interaction between the nearest neighbor ions, leading to a quenching phenomenon. Furthermore, the photometric analysis revealed that the correlated color temperatures (CCTs) associated with the emitted white light were found to be higher than 4000 K. Thus, based on these characteristics, it can be inferred that the prepared nanophosphor has the potential to be utilized as a cool white-emitting nanophosphor for single-phased WLEDs application.

Colour-tunable and warm white light emitting thermally stable Dy3+/Sm3+ co-activated tungstate-tellurite glasses for photonic applications

Transparent single Dy3+, Sm3+, and Dy3+/Sm3+ co-activated tungstate-tellurite (TWKZBi) glass matrices were synthesized via melt-quenching process. The optical features of the prepared glass matrices were examined with the aid of the absorption spectra. Under various excitation wavelengths (366, 388 and 454 nm), Dy3+ doped TWKZBi (TWKZBiDy) glasses revealed a prevailing emission peak ⁓575 nm related to the yellow band (4F9/2 → 6H13/2) transition, while Sm3+ doped TWKZBi (TWKZBiSm) glass matrices reveal strong intense emission peak at ∼600 nm associated with the orange-red band (4G5/2 → 6H7/2) transition. The emission intensity progressively surges with an increment in Sm3+ ion content (up to 1.5 mol%), confirming the ET mechanism between Dy3+ and Sm3+ ions. Application of Dexter's ET formulation with the Reisfeld's approximation revealed that the ET mechanism involves a non-radiative dipole-dipole (d-d) interaction between Dy3+ and Sm3+ ions. The average lifetime (τavg) values for the 4F9/2 state of Dy3+ ions in the TWKZBiDySm glass sample was measured and found that these values decreased with increasing Sm3+ ion content. In addition, the ET efficiencies (ηDy→Sm) of the TWKZBiDySm glass matrices were evaluated using the lifetime curves. The color coordinates (x, y) and the correlated color temperature (CCT) values of the co-activated glass samples were estimated. Based on the chromaticity coordinates and CCT values, it was found that the desired color of the TWKZBiDySm glass samples can be modulated from warm white light to orange-red light via precisely adjusting the concentration of Sm3+ ions and at selected excitation wavelengths. Furthermore, the emission intensity observed at 373 K was 83.83 % compared to the emission intensity at ambient temperature, indicating the excellent thermal stability of the TWKZBiDySm glasses prepared. The above results confirm that the prepared Dy3+/Sm3+ co-activated TWKZBi glass matrix can be a promising candidate for white light and other photonic devices.

Growth and spectral properties of a novel praseodymium-doped alpha-barium borate laser crystal

A novel Praseodymium-doped borate (Pr:α-BBO) laser crystal was grown successfully by using the Czochralski method. The phase structure, absorption and fluorescence lifetime, as well as blue laser diode (LD) pump performances of Pr:α-BBO were totally studied. The segregation coefficient and valence state of Pr ions in the crystals were investigated using inductively coupled plasma atomic emission spectroscopy and X-ray photoelectron spectroscopy. A 450 nm blue LD was employed to carry out a pump experiment on the Pr:α-BBO slab crystal with a doping concentration of 0.22 at.%. The main emission peaks of Pr3+ ions in the orange-red light band were found to be at 611.5 nm, 634.7 nm, and 638.3 nm. The experimental results show that the Pr:α-BBO crystal exhibits higher orange light fluorescence emission performance, with an emission peak intensity at 611 nm that is 2.1 times stronger than that at 635 nm due to the splitting of the 3P0→3F2 transition (635 nm). By optimizing the Pr:α-BBO laser crystal growth process and further solid-state laser experiments, it can be expected to have broad applications in laser medicine, spectral detection, and nonlinear optical frequency conversion fields.

Synthesis and Photoluminescence Modulation of Cs4Cd1-xMnxBi2Cl12-Based Two-Dimensional Layered Double Perovskites.

Two-dimensional (2D) layered double perovskites have attracted much attention because of their excellent photoelectric properties. However, few reports have been published on the synthesis of 2D layered double perovskites from halide perovskites as precursors. Here, we report that CsCdCl3 and Cs3Bi2Cl9 were synthesized by the coprecipitation method, and a two-dimensional layered double perovskite Cs4CdBi2Cl12 was readily synthesized by mixing the two halide perovskites. We doped different amounts of Mn2+ into CsCdCl3 to form CsCd1-xMnxCl3, which introduced impurity states into the energy level and exhibited an orange-red light emission that is characteristic of Mn2+. A series of 2D layered double perovskites Cs4Cd1-xMnxBi2Cl12 were synthesized from CsCd1-xMnxCl3 and Cs3Bi2Cl9, which showed a bright orange-yellow luminescence under ultraviolet excitation. The presence of high concentrations of Cd2+ in the two-dimensional layered double perovskites weakened the strong Mn-Mn coupling and suppressed the energy transfer to defects, thus minimizing nonradiative decay and promoting efficient energy transfer. Our work provides a new concept for the synthesis of low-dimensional metal halide perovskites with unique optical properties.

Thermally stable illuminating characteristics of Tb3+/Sm3+ ions activated BaO–SrO–Al2O3–B2O3–SiO2 glasses for photonic applications

A set of Tb3+ and Tb3+/Sm3+ co-doped barium strontium aluminium borosilicate (BaSrAlBSi) glasses were produced to examine optical properties carefully. The transparent BaSrAlBSi glass amorphous nature was established by the XRD pattern. The absorption profile demonstrates the various peaks from n-UV to NIR range caused by the Tb3+ as well Sm3+ ions in BaSrAlBSi glass. BSi:Tb1.0 glasses give intense green emission under λex = 368 nm, BSi:Sm1.0 glasses exhibit the emission spectrum caused by the transitions of the Sm3+ ions. The Tb3+/Sm3+ co-doped BaSrAlBS glasses exhibit a mixture of emission exhibited by individual ions when excited at 368 nm, whereas it exhibits only red-orange light emission when excited under 402 nm. The PL lifetimes demonstrated a reduction in decay time as Sm3+ ions concentration increased in Tb3+ doped BaSrAlBSi glasses. CIE coordinates show the green emission was tuned towards the warm white region via co-doping of Sm3+ in Tb3+ doped BaSrAlBSi glasses. The strong thermal stability of BSi:TbSm1.0 glass is confirmed via a temperature-dependent emission profile. The observed results indicate that the transparent BSi:TbSm1.0 glasses as made will be directly useful for photonic device applications as n-UV pumping results in green warm white and orange emissions.

Synthesis, Structural and Fluorescence Investigations of Novel Li2Ba5W3O15:Sm3+ Phosphors for Photonic Device Applications.

In the current study, Sm3+ ions doped Lithium Barium Tungstate (Li2Ba5W3O15) (LBW) phosphors with the ability to emit orange-red light were made using the traditional high-temperature solid-state reaction technique. The structure and phase of the as-synthesized phosphor samples were examined via X-ray diffraction (XRD) patterns. The diffraction peaks of the undoped LBW and Sm3+ ions doped LBW phosphors closely resemble those of the Joint Committee on Powder Diffraction Standards (JCPDS) pattern with card number 01-072-1717. Scanning electron microscopy (SEM) was employed for the analysis of the morphological characteristics of the synthesized phosphor material. Fourier Transform Infrared (FT-IR) spectroscopy was used to study several vibrational and molecular bands present in the host matrix. Using diffuse reflectance spectra (DRS), the optical band gap values (Eg) were evaluated by applying Tauc's method. The photoluminescence (PL) spectra characteristics at λex = 336nm indicate the emission of dopant ions (Sm3+) in the deep orange-red region corresponding to 4G5/2 → 6H5/2 transition (at 581nm) with concentration quenching after 2mol % of Sm3+ ions. Using the PL spectra, the CIE chromaticity coordinates of LBWS2.0 phosphor were estimated and found in the deep visible orange-redarea, indicating the potential use of the prepared phosphor material for phosphor-converted white light emitting diodes (w-LEDs) applications. Double exponential behaviour can be seen in the PL decay spectralprofiles obtained under λem = 581nm and λex = 336nm. The experimental lifetimes (τexp) decrease as the concentration of Sm3+ ions rise. The temperature-dependent PL (TDPL) and activation energy results show that the as-synthesized phosphor has considerably superior thermal stability. The results of the current research contemplate us the applicability of Sm3+ ions doped LBW phosphor for photonic devices such as w-LEDs.

Synthesis and photoluminescence properties of novel orange-emitting Ba2Gd8(SiO4)6O2: Sm3+ phosphors for white LED applications

The solid-state method was utilized to prepare a series of orange-red-emitting Sm3+-doped Ba2Gd8(SiO4)6O2 phosphors. The X-ray powder diffraction patterns indicated that the synthesized phosphors had a pure hexagonal phase. X-ray energy dispersive spectroscopy studies confirmed the elemental composition and distribution of the different elements present in the Ba2Gd8 (SiO4) 6O2: Sm3+ powder. The Sm3+-doped Ba2Gd8 (SiO4) 6O2 phosphors exhibited bright luminescence under 407 nm excitation, with a primary peak at 600 nm. Spectral analysis showed that the Sm3+-doped Ba2Gd8 (SiO4) 6O2 phosphors emitted bright orange-red light. Concentration quenching was detected in Sm3+-doped Ba2Gd8(SiO4)6O2 phosphors with a 0.03 mol% concentration of Sm3+ ions because of the multipolar interaction between the two closest Sm3+ ions. The effective orange-red emission suggests the use of Sm3+-doped Ba2Gd8(SiO4)6O2phosphors for white light-emitting diodes.

Electroactive Dyes Based on 1,8-Naphthalimide with Acetylene Linkers as Promising OLED Materials - the Relationship Between Structure and Photophysical Properties.

Four A-π-D-π-A type small organic molecules with 1,8-naphthalimide motifs were successfully synthesised. The designed compounds are built of two 1,8-naphthalimide units linked via ethynyl π-linkages with selected functionalised donor motifs i. e. 2,2'-bithiophene, fluorene, phenothiazine and carbazole derivative. The synthesis based on Sonogashira cross-coupling allowed us to obtain the presented dyes with good yields. The resulting symmetrical small molecules' optical, electrochemical and thermal properties were thoroughly investigated, and their potential applicability for the OLED devices was demonstrated. In addition, the relationship between molecular structure and properties was considered by employing experimental and theoretical studies. As a result of using various donor groups, it was possible to achieve efficient electroluminescence in the range from green (DEV4) to orange-red light (DEV3) with a maximum luminance of 3 820 cd/m2 for DEV4. Upon the insertion of an acetylene linker to the designed molecules, the free rotation of D and A fragments, and hence the effective π-electron communication within the entire molecule, is possible, which was confirmed by DFT studies. The obtained dyes are characterised by high thermal stability, reversible oxidation-reduction process, satisfactory optoelectronic properties and good solubility in organic solvents, which is advisable for the application in small molecular organic light-emitting diodes (SM-OLEDs) technology.

Promising reddish-orange light as Eu3+ incorporated in zinc-borosilicate glass derived from the waste glass bottle

Eu3+ incorporated zinc-borosilicate glass was synthesized using melt-quenching method. XRD and FTIR verified the amorphous nature of the samples. The absorption spectra indicate the Eu3+ ions in the UV-visible region at ∼394 nm. The direct and indirect band gap decrease from 5.152 eV to 5.082 eV and 4.133 eV to 3.837 eV, respectively. Meanwhile, the refractive index decrease from 2.145 to 2.202, while the Urbach energy ranges from 0.682 eV to 0.733 eV. All the samples have a good transmission percentage at 70–75%. Under the excitation of 400 nm, the intensity of the PL spectra increased when the Eu3+ dopant increased. The optimum content for Eu3+ incorporated ZnO–B2O3–GB glass is 3 wt.% among the other Eu3+ content (0, 1, and 2 wt.%) in this work. The reddish-orange emission at 612 nm (5D0 → 7F2) indicates the most intense emission and the CIE chromaticity coordinates imply in the reddish-orange region.

Light intensity and spectral quality modulation for improved growth kinetics and biochemical composition of Chlamydomonas reinhardtii.

Effective strategies to optimize algal growth and lipid productivity are critical for the sustainable production of biomass for various applications. Light management has emerged as a promising approach, but the intricate relationship between light intensity, spectral quality, and algal responses remains poorly understood. This study investigated the effects of different light qualities (blue, red-orange, and white-yellow) and intensities (45-305 μmol/m2·s) on Chlamydomonas reinhardtii. Red-orange light exhibited the highest promotion of biomass growth and lipid productivity, with specific growth rates of 1.968 (d-1) and biomass productivity of 0.284 (g/L/d) at 155 μmol/m2·s and 205 μmol/m2·s, respectively. Within the intensity range of 205 μmol/m2·s to 305 μmol/m2·s, lipid mass fractions ranged from 10.5% w/w to 11.0% w/w, accompanied by lipid concentrations ranging from 68.6mg/L to 74.9mg/L. Red-orange light positively influenced carbohydrate accumulation, while blue light promoted protein synthesis. These findings highlight the importance of optimizing light quality and intensity to enhance algal biomass productivity and manipulate biochemical composition. Understanding the complex relationship between light parameters and algal physiology will contribute to sustainable algal cultivation practices and the use of microalgae as a valuable bioresource.

A comparative analysis on the spectroscopic qualities of modifiers and Sm3+ ions integrated bismuth boro-tellurite glasses for visible orange appliances

Considering the striking features of trivalent samarium ions that can yield novel optoelectronic devices, a set of additive-reliant Sm (III) ions doped bismuth boro-tellurite (BTBiCofXfSm1.0) glasses was synthesized and their physical, structural and lasing features were studied for potential orange emission photonic applications. Structural and elemental investigations are done via XPS and EDX analyses. The spectroscopic paraments as a function of the added additive were analysed to discover the suitable glass. The evaluation of bonding parameters from the absorption studies verified the ionic bonding between the oxygen ligand and the Sm (III) ions in the glasses with respect to the additives. Four luminescence emission bands were observed from the emission spectra and the 4G5/2 → 6H7/2 transition is found to be hypersensitive which denotes intense orange emission. The lasing action determining features like transition probability (Arad), branching ratio (βR) and stimulation emission cross section (σsec) are found to be higher for the Ba oxide containing glass which is a potential medium for red-orange light emission and visible orange photonic applications. The higher quantum efficiency (75.83%) of the Ba containing glass under 476 nm excitation indicates its suitability in high-quality orange light applications. The Judd Ofelt and CIE colorimetric investigations discovered that the studied glass are high-quality media for optoelectronic applications.

Highly Efficient Orange-Red Emission in Sm3+-Doped Yttrium Gallium Garnet Single Crystal

High-quality single crystals with empirical composition Y2.96Sm0.04Ga5O12 (YGG: Sm3+) were successfully prepared by the optical floating zone method for the first time and compared with related single crystals of Y2.96Sm0.04Al5O12 (YAG: Sm3+). With both crystals, XRD showed that Sm3+ entered the cubic-phase structure. Optical absorption spectra produced a series of peaks from Sm3+ in the 250 nm to 550 nm range, and photoluminescence excitation (PLE) spectra detected at 613 nm showed strong excitation peaks at 407 nm and 468 nm. A strong emission peak at 611 nm (orange-red light) was observed in the photoluminescence (PL) spectra under excitations at both 407 and 468 nm, respectively, but it was much brighter under excitation at 407 nm. Furthermore, with both emission spectra, the peaks from the YGG: Sm3+ crystal were significantly more intense than those from the YAG: Sm3+ crystal, and both experienced a blue shift. In addition, under excitation at 407 nm, the color purity of the emitted orange-red light of YGG: Sm3+ was higher than that of the YAG: Sm3+ crystal, and the fluorescence lifetime for the 4G5/2 → 6H7/2 transition of YGG: Sm3+ was longer than that of the YAG: Sm3+ crystal. The optical properties of the YGG: Sm3+ crystal are better than those of the YAG: Sm3+ crystal.

Designing ultra-highly efficient Sm3+ activated SrLaAlO4 orange-red emitting phosphor towards security encoding, hydro-gels, flexible displays and personal identification

SrLaAlO4:Sm3+ (1–5 mol %) nanophosphors (SLAO:Sm3+ NPs) has been developed. Under stimulation at 402 nm, the Sm3+ ions shows the transition of 4G5/2→ 6H7/2 enabled the phosphor to emit a powerful orange-red light at 602 nm. Based on the photoluminescence emission (PLE) profiles, the International Commission on Illumination calculated the colour coordinates (CC), correlated colour temperature (CCT) and colour purity (CP) values. Comparisons were made between the acquired CC and the normal National Television System Committee (NTSC) coordinates. Additionally, the applicability of the SLAO:2Sm3+ NPs was evaluated to visualize the latent fingerprints on smooth surfaces using the powder dusting method. The obtained latent fingerprint images exhibited good sensitivity, high contrast, and appreciable ridge details. To develop anti-counterfeiting inks that mark on multiple surfaces with high resolution without spreading and tracing, fluorescent phosphor was fabricated with the required thickening agent. The created pattern in the ink above immediately formed and lighted with bright orange and red fluorescence emission when exposed to UV light. The findings showed that the optimized NPs can generate a lot of interest for application in security encoding and personal identification.

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.

Three novel Mn2+-based halides: Heat/acid-induced structural transformation and luminescent conversion

Mn2+-based halides show great promise for solid-state lighting and display applications owing to their structural flexibility and excellent luminescence properties. Herein, three hybrid manganese halides (N-AEP)[MnBr3(H2O)3]2·Br (1), [(N-AEP)2MnBr6]·2Br (2) and [(N-AEP)2MnBr4]·3Br(H2O) (3) with the same organic ligand have been successfully synthesized by adjusting various HBr level or temperature of growth solutions. Systematic characterizations of halides including crystal structure, thermal and photophysical properties were carried out. Their distinct inorganic groups lead to the various luminescence colors: purple-red light in 1, orange-red light in 2 and green light in 3. Some interesting physicochemical features, for 1 the temperature-dependent emission properties, 2 the satisfactory thermostability with higher PLQY (13.36%), and 3 the weak ferromagnetic coupling effect, broaden their application prospects. This paper offers sufficient synthetic experiences for Mn2+-based halides with different inorganic groups in detail, and provides a reasonable research scheme for their optical properties.

Orange-red-emitting (Sr,Ba)3SiO5:Eu2+ phosphor-in-glass film for enhanced color rendering of laser lighting

Nitride red-emitting materials exhibit severe luminance saturation and are thus not suitable for achieving enhanced color rendering in laser lighting applications. The silicate luminescent material (Sr,Ba)3SiO5:Eu2+ displays excellent stability and can emit orange-red light when excited by blue laser light, making it a promising candidate for realizing high-performance laser lighting. In this study, (Sr,Ba)3SiO5:Eu2+ phosphor-in-glass (PiG) films were prepared on a sapphire substrate, and the influences of preparation temperature, mass ratio of phosphor to glass frit (PtG ratio), and film thickness on the application performance of PiG film were analyzed. The (Sr,Ba)3SiO5:Eu2+ PiG film with a PtG ratio of 1:1 and a film thickness of ∼50 μm prepared at 475 °C exhibited optimal comprehensive luminescence performance. This film exhibited a luminous saturation threshold of 5.98 W/mm2, a maximum luminous flux of 372.3 lm, and a luminous efficiency of 62.3 lm/W at the luminous saturation threshold. The maximum luminous flux of the (Sr,Ba)3SiO5:Eu2+ PiG film was 77.6% higher than that of the CaAlSiN3:Eu2+ nitride PiG film. Finally, through the incorporation of green-emitting YAGG:Ce3+ phosphor into the (Sr,Ba)3SiO5:Eu2+ PiG film, laser-driven white light with a luminous flux of 531.7 lm and a high color rendering index (CRI) of 83.4 was realized.