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White light-emitting diodes (WLEDs) have become essential to various aspects of our daily lives. However, the absence of a strong cyan emission significantly hinders the development of full-spectrum WLEDs that could achieve high-quality applications. Here, a feasible method is introduced to synthesize highly luminescent and stable CsPbBr3 by employing an efficient dual-matrix encapsulation technique. Sodium citrate (SC) is utilized as a matrix to disperse these CsPbBr3 nanomaterials, thereby reducing self-absorption and energy transfer. In addition to functioning as a matrix, SC also passivates the perovskite nanomaterials, resulting in an increased photoluminescence quantum yield (PLQY) and enhanced stability of the perovskite. Notably, the stability of the perovskite, especially its resistance to water, is significantly enhanced after encapsulating the composite within poly-(methyl methacrylate) (PMMA). A series of full-spectrum WLEDs with variable color temperatures ranging from 2763 to 7145 K and high color rendering indices (90–96) were fabricated using SC-CsPbBr3@PMMA in combination with commercially available YAG and red phosphors CaAlSiN3:Eu2+. This research opens up new avenues for the utilization of perovskite nanomaterials in the development of next-generation full-visible-spectrum WLED lighting. [ABSTRACT FROM AUTHOR]

Red-emitting phosphors play a pivotal role in the field of lighting technologies. This study introduces an innovative class of Li 6 SrEu 2 Sb 2 O 12 garnet-structured phosphors, distinguished by the resistance to concentration quenching. A comprehensive examination of the crystal structure, electronic configuration, and photoluminescence characteristics has been conducted. Notably, the doping Eu3+ ions and their doping concentrations barely affected the crystal structure and morphology, and the band gap slightly decreased as the doping concentration increased. Interestingly, the obtained samples exhibit an ultra-high color purity, good thermal stability (78.60 % at 423 K), and suitable internal photoluminescence quantum yield (44.18 %). Consequently, a phosphor-converted white LED has been successfully fabricated, which boasts an outstanding correlated color temperature of 3271 K. Beyond conventional application, this research also introduces the concept of innovative flexible-transparent displays harnessing the phosphor film. Overall, this work has synthesized a groundbreaking red-emitting phosphor, poised to enhance traditional lighting sources and potentially pave the way for new applications in the field of advanced optical displays. [ABSTRACT FROM AUTHOR]

This study focuses on the facile combustion synthesis of highly luminescent Y2O3:Sm3+, Gd3+ nanophosphors, bringing down the thermal budget to a minimum of 500 K. When Sm3+ ions are doped in the Y2O3 cubic crystal system of bandgap 5.6 eV and studied under a down-conversion excitation of 260 nm, the emission spectra offered an intense vermilion color at 608 nm due to the 4G5/2 → 6H7/2 transition within the Sm3+ ions. The Y2O3:2wt%Sm3+ matrix is co-doped with 3wt%Gd3+, highlighting 100% pure vermilion emission 4.21 times higher than doped samples, which is a perfect choice for domestic lightening owing to better eye compatibility. Further, post-annealing is performed to improve the structural parameters and luminescence properties, creating sufficient alterations in the crystal lattice. It is professed that Y2O3:Sm3+, Gd3+ nanophosphors can be effectively used in optoelectronic devices, owing to their enhanced crystallinity and photoluminescence properties resulting from the Gd3+ → Sm3+ energy transfer efficiency of 75.15%. [ABSTRACT FROM AUTHOR]

The common flower Clitoria ternatea is gifted with organic dyes anthocyanin delphinidin and betalains betacyanin that exhibit broad emission peaks centered at 490 nm and 630 nm. These fresh emission bands in the blue-green and red regions make it a potential white light source that can swap the conventional rare-earth doped phosphor materials. By this line, the extract shows decent emission in its solution state. However, the emission intensity reduces rapidly after a while, owing to the high decay rate of organic dyes in their pure form. Thus, the floral extract is combined with the antioxidant La2O3, reducing the luminescence decay to a noticeable value. The complex formation does not alter the innate La2O3 crystal structure, identified by the XRD peaks, but aids with near-white emission. Upon complex formation, the optical band gap of the host La2O3 falls to the semiconductor range, from 5.1 eV to 2.5 eV. White light emission from La2O3: Clitoria ternatea complex is studied for different extract concentrations and heating conditions, and deemed as a potential replacement for conventional rare-earth doping. [ABSTRACT FROM AUTHOR]

The development of eco-friendly luminescent materials is imperative for the advancement of phosphor-based technologies. This study corroborates the self-reduction of Eu3+ to Eu2+ through analyses utilizing photoluminescence (PL), excitation spectroscopy (PLE), and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) calculations demonstrate that Eu2+ ions can efficaciously substitute Ba2+ ions within the BaGa 4 S 7 lattice, preserving its structural integrity. Upon blue light excitation, BaGa 4 S 7 :Eu2+ manifests a robust green emission attributed to Eu2+ ions, showcasing a peak wavelength near 526 nm. The quantum yield (QY) of BaGa 4 S 7 :Eu2+ is remarkably high, registering at 74.8 %. Moreover, the temperature-dependent luminescence properties of BaGa 4 S 7 :Eu2+ phosphor were subjected to thorough investigation. Water resistance assays indicate that the sample preserves 76 % of its initial luminous intensity following 40 days of aqueous immersion. Additionally, BaGa 4 S 7 :Eu2+ based phosphor-converted white light-emitting diodes (WLEDs) demonstrate emission of high-quality white light. This unique water-resistant green emission sulfide phosphor is expected to have potential applications in lighting fields. [ABSTRACT FROM AUTHOR]

This manuscript presents a comprehensive evaluation of Cs3Sb2I9 (Eg = 1.95 eV) as a potential absorber for indoor photovoltaic (IPV) applications. Using computational modeling, we developed a baseline model of the device structure (FTO/TiO2/Cs3Sb2I9/PolyTPD(poly(N,N'-bis-4-butylphenyl-N,N'-bisphenyl)benzidine)/Au), which experimentally achieved a power conversion efficiency (PCE) of 3.7% under white light-emitting diode (WLED) illumination at 3.2 W m−2 (1000 lx). By increasing the source transmission power density from 3.2 W m−2 (6%) to 53.31 W m−2 (100%), we significantly enhanced the device's performance. Key parameters such as absorber layer thickness and defect density, along with parameters of the electron transport layer (ETL) and hole transport layer (HTL), were optimized, such as doping concentration, electron affinity (χ), and bandgap (Eg), were optimized. Our simulations demonstrated that the optimized device can achieve a remarkable PCE of 38.77%, with an open-circuit voltage (VOC) of 1.47 V, a short-circuit current density (JSC) of 1.55 mA cm−2, and an excellent fill factor (FF) of 89.09%. Additionally, we proposed a new device architecture, AZO/TNT/Cs3Sb2I9/SrCu2O2/Ni, capable of delivering 38.77% PCE under WLED illumination. This study highlights the critical role of computational modeling in optimizing device design, offering a cost-effective and efficient alternative to experimental methods. [ABSTRACT FROM AUTHOR]

Abstract The common flower Clitoria ternatea is gifted with organic dyes anthocyanin delphinidin and betalains betacyanin that exhibit broad emission peaks centered at 490 nm and 630 nm. These fresh emission bands in the blue-green and red regions make it a potential white light source that can swap the conventional rare-earth doped phosphor materials. By this line, the extract shows decent emission in its solution state. However, the emission intensity reduces rapidly after a while, owing to the high decay rate of organic dyes in their pure form. Thus, the floral extract is combined with the antioxidant La2O3, reducing the luminescence decay to a noticeable value. The complex formation does not alter the innate La2O3 crystal structure, identified by the XRD peaks, but aids with near-white emission. Upon complex formation, the optical band gap of the host La2O3 falls to the semiconductor range, from 5.1 eV to 2.5 eV. White light emission from La2O3: Clitoria ternatea complex is studied for different extract concentrations and heating conditions, and deemed as a potential replacement for conventional rare-earth doping.

Eu2+‐doped phosphors have attracted the great attention of researchers in the past decade. However, Eu2+ dopant in inorganic hosts often suffers from the self‐oxidation effect, therefore causing the attenuated emission intensity and quantum efficiency. In this regard, developing Eu2+ doped phosphors with the prohibited self‐oxidation effect of Eu2+ and increased thermal stability is urgently required. Herein, an innovative cyan‐light emitting Li2CaSiO4:Eu2+/Eu3+, Lu3+ (LCSO) phosphor is designed. Both experimental results and theoretical calculations demonstrate that adding Lu3+ restricts the self‐oxidation of Eu2+ into Eu3+, thus improving the emission of Eu2+. Meanwhile, the Lu3+ introduction brings out excellent thermal stability. Finally, an efficient WLED with a color temperature (CCT) of 4573 K and a high color rendering index (Ra) of 84.2 is obtained using the as‐prepared phosphor due to the perfect compensation of the cyan light. As the introduction of Lu3+ improves the stability of Eu2+, a much greater difference in PL decay rate between Eu2+ and Eu3+ in LCSO is reached, thereby improving their sensitivity in temperature sensing. The strategy of Lu3+ introduction for prohibiting the self‐oxidation of Eu2+ for efficient and stable Eu2+ emission may stimulate some new ideas in designing high‐performance phosphors for more diverse applications. [ABSTRACT FROM AUTHOR]

Site‐selective occupation generated by ion doping into crystal lattices is an effective way to explore new matter and regulate luminescent properties. Herein, equiv. M2+ (Ca, Sr, Ba) is partially replaced each other to formulate multiple doped sites in Li2MSiO4: Eu2+ (LMSO: Eu2+). As the luminescence center, Eu2+ selectively occupies different sites to regulate luminescent color in the visible spectrum ranging from blue to orange, and ultimately functionality improvement. The Huang‐Rhys factor is quite small and the resulting phosphors display an ultrahigh thermal stability for optical thermometry. Besides, utilizing synthesized phosphors combined with the InGaN chip generates high‐quality full‐spectrum white light. Under X‐ray irradiation, LMSO: Eu2+ (M = Ca, Sr, Ba) exhibits great X‐ray imaging ability, the detection limit of X‐ray reaches 0.18, 0.075, and 0.12 µGy s−1. This work presents great potentiality of synthesized phosphors in the fields of solid‐state lighting and X‐ray imaging. [ABSTRACT FROM AUTHOR]

A series of Eu3+-doped self-activated Zn3(VO4)2 (x = 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0 mol%) phosphors have been successfully synthesized by a high-temperature solid-state reaction method. Powder X-ray diffraction patterns of the samples were measured, indicating the successful formation of phosphors with orthorhombic crystal structure. Field emission scanning electron microscopy was used to evaluate the morphology and particle size of the prepared samples, and the composition was analysed by energy X-ray dispersion technique. In addition, prepared samples were analysed by characterization techniques such as transmission electron microscopy, Fourier transform infrared spectroscopy, UV diffuse reflectance spectroscopy and photoluminescence (PL). The PL properties of prepared samples show green–red emission at 395 nm excitation and strong red emission at 467 nm excitation. Under 395 nm excitation, PL emission shows broad green emission band due to self-luminescence properties of vanadate ions. With the doping of Eu3+ ions, (VO4)3– ions transfer their energy to Eu3+ ions. The highest red emission intensity was observed in 8 mol% Eu3+ concentration. The CIE spectral coordinates and colour-correlated temperature of the as-prepared Zn3(VO4)2:Eu3+ phosphors were studied in detail at various Eu3+ concentrations. The obtained PL results demonstrate that the as-prepared Zn3(VO4)2:Eu3+ phosphors can be investigated as green–orange–red emitting phosphors in the future for white light-emitting diodes applications. [ABSTRACT FROM AUTHOR]

Highly thermostable RhB@Zr-Eddc composites with the Rhodamine B (RhB) enclosed into the nanocages of Zr-Eddc was synthesized by one-pot method under hydrothermal conditions, whose structure, morphology and stability were characterized through the X-ray powder diffractometry (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). RhB@Zr-Eddc showed the highly thermal stability up to 550°C and emitted the bright red-light emission at 605 nm, which could highly selective detect the nitrofurazone (NFZ) among eleven other antibiotics in aqueous solution. Furthermore, via combining the RhB@Zr-Eddc with commercial green phosphor (Y3Al5O12:Ce3+, Ga3+), the mixture was encapsulated onto a 455 nm blue LED chip, creating an excellent white light emitting diode (WLED) device with the correlated colour temperature (CCT) of 4710 K, luminous efficiency (LE) of 43.17 lm/w and Color Rendering Index (CRI) of 89.2. [ABSTRACT FROM AUTHOR]

Yellow-emitting pure Zn3 V2 O8 phosphors were successfully synthesized via a simple high-temperature solid-state method using BaF2 as heat-assisted co-solvent. The purity of Zn3V2O8 was determined by X-ray diffraction (XRD), and its optical properties were analyzed by PLE/ PL spectrum, thermal quenching spectrum and fluorescence lifetime curve analysis. The results show that Zn3V2O8 exhibits strong broadband emission in the range of 400 - 800 nm under the excitation of 360 nm, which is attributed to ³T2→¹ A1 and ³T1→¹ A1 transition. Zn3 V2 O8 can emit bright yellow light and the optimum emission wavelength is 550 nm. Under 550 nm, Zn3 V2 O8 phosphors show wide absorption bands in the range of 200 - 450 nm. The decay time of Zn3V2O8phosphor is 1. 67 ms and its inner quantum efficiency reaches 47. 09% at room temperature. Moreover, when the temperature rose to 140 °C, its emission intensity retention could reach 25. 1% of its initial intensity at room temperature, which is higher than that of other garnet structure vanadate materials. Therefore, Zn3V2O8 phosphor as a novel yellow light source for white light-emitting diode devices has potential advantages in terms of low cost and the ability to be mass-produced. [ABSTRACT FROM AUTHOR]

Red-emitting phosphors are crucial for sustainable white-light-emitting diodes (WLEDs) used in lighting. These materials significantly enhance the lighting and backlit display quality of phosphor-converted white LEDs (pc-WLEDs) by overcoming red deficiency. Luminescent properties of rare earth activated fluoride based inorganic compounds are most investigated due to its excellent spectral characteristics. In this paper we report the novel Na2LiAlF6 luminescent host material activated with Eu3+ rare earth ions synthesized by wet chemical method. The spectral analysis revels the excitation spanning in near UV region while emission spectra depict characteristic peaks transitioned in accordance with 5D0 to 7F1 and 7F2. Effect of concentration quenching, Color purity and temperature studied briefly which demonstrates that the prepared red emitting phosphor is useful in various device applications such as phosphor converted White light emitting diodes for fulfilment of red deficiency, solid state lighting, display technology as an essential red component.

[Display omitted] • Novel eye-sensitive Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :Tb3+/Mn4+ were synthesized by simple co-precipitation strategy. • Red phosphor presents extremely strong ZPL at ∼ 625 nm and high color purity. • Red and green phosphors exhibit inherently outstanding thermal stability and moisture resistance. • Red and green phosphors coated directly on UV chip can achieve white emission. • The fabricated WLED devices show excellent electroluminescent properties. Novel eye-sensitive Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :Tb3+ green and Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :Mn4+ red oxyfluoride phosphors with extremely strong absorption in the UV region were designed and synthesized by simple co-precipitation strategy. Particularly, Tb3+ ions were doped in this matrix for the first time, which greatly improves their absorption efficiency in the near ultraviolet region (367 nm) and emits sharp green light (544 nm). In addition, the Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :Mn4+ red phosphors have strong zero phonon line (ZPL) emission at 625 nm, which is conducive to improving the sensitivity of human eye and color purity. Meanwhile, the optical properties of the red phosphor are significantly enhanced via doping K+ cations as charge compensators. Crystal field environment and nephelauxetic effect of the as-prepared phosphors before and after K+ cation doping were systematically analyzed. Moreover, these synthesized red/green phosphors have good thermal stability and moisture resistance. Remarkably, the as-prepared Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :5%Mn4+ or K 0.9 Ba 2.1 Nb 2 O 2 F 12 (H 2 O) 2 :5%Mn4+ red phosphors can be directly mixed with the as-synthesized Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :13%Tb3+ green phosphor coating on 365 nm near-ultraviolet LED chip to package WLED devices with excellent electroluminescence performance. These findings are conducive to opening an avenue for screening the unique structure of optical materials. [ABSTRACT FROM AUTHOR]

Extensive research has been conducted on all-inorganic CsPbI 3 nanocrystals (NCs) due to their exceptional optical properties. In this study, we successfully prepared CoBr 2 -doped CsPbI 3 NCs in Lithium-borosilicate using the conventional melting quenching approach. We investigated the optical characteristics of CsPbI 3 NCs glass doped with varying amounts of CoBr 2. Remarkably, the samples exhibited outstanding water and thermal stability and tunable emission ranging from 702 to 652 nm. Interestingly, the CsPbI 3 NCs glasses doped with CoBr 2 demonstrated significantly enhanced photoluminescence quantum yields (PLQYs), which increased from 8 % to 32 %. Furthermore, by mixing a red CsPbI 3 NCs glass doped with 0.5 mol CoBr 2 and a green CsPbBr 3 under a blue LED chip, we effectively generated a WLED which achieved (0.3341, 0.3360) of chromaticity coordinate (CIE), 5775.35 K of a correlated color temperature (CCT) that close to positive white light (0.330, 0.330) and the color rendering index (CRI) 79.4. This study provides a new technique in the field of metal ion-doped perovskite NCs, providing a valuable reference for future research and demonstrating possible applications in LEDs. [ABSTRACT FROM AUTHOR]

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In an effort to obtain a novel cyan‐emitting phosphor, the [K1‐xRbx]3GdSi2O7: yCe3+ materials (x = 0, 0.1, 0.2, 0.3, 0.4, y = 0, 0.005, 0.01, 0.02, 0.03, 0.04) are synthesized via a solid‐state reaction pathway, and their crystal structure and luminescence behaviors are studied systematically. The chemical substitution of Rb+ in the K+ sites can enlarge the K3GdSi2O7 host lattice and help to the blue‐shifting of emission band of Ce3+ ions due to the decreased crystal field splitting effect. It is also confirmed that the Ce3+ ions tend to enter [Gd1O6] and [Gd2O6] polyhedrons simultaneously. Consequently, the [K0.7Rb0.3]3GdSi2O7: Ce3+ phosphor yields a broadband cyan emission centered at 492 nm with the full width at half maximum (FWHM) of ∼115 nm upon 365 nm excitation. The optimal concentration of Ce3+ dopant is determined to be 0.01, and the concentration quenching effect can be attributed to the dipole−dipole interactions. The white light emitting diode (WLED) device fabricated by employing the discovered [K0.7Rb0.3]3GdSi2O7: 0.01Ce3+ phosphor displays a high color rendering index (Ra = 91.7) and a low correlated color temperature (CCT = 3749 K). This work may promote the development of cyan phosphors for near ultraviolet‐converted WLEDs with high performance. [ABSTRACT FROM AUTHOR]

A series of orange-red phosphors, Na5 Y1 - x (MoO4)4 - y (WO4)y: xSm3+ (x =0 ~0. 10, y =0 ~4), were synthesized by high temperature solid state method. The properties of the phosphor samples were studied by means of X-ray diffraction, transmission electron microscope, normal/variable temperature fluorescence emission spectrum, fluorescence excitation spectrum, fluorescence dynamic attenuation curve, CIE chromaticity coordinates and so on. XRD results show that the phase of the synthesized samples is consistent with the standard of Na5 Y(MoO4)4, and the phase structure of the materials is unchanged by introducing Sm3+ or (WO4)2 -. Under the excitation of 406 nm, Na5 Y0. 92 (MoO4)3 (WO4):0. 08Sm3+ has the highest emission intensity. With increasing doping concentration of Sm3+, the concentration quenching phenomenon appears, and the main reason for the concentration quenching is attributed to the electric dipole-electric dipole interaction. The study found that the doping of rare earth ions in the Na5 Y(MoO4)4 matrix would cause electronegativity changes and lattice distortion. The introduction of (WO4)2 - anionic groups into Na5 Y1 - x (MoO4)4:xSm3+ can make up for the defects caused by the doping of Sm3+ and further improve the luminescence performance of Na5 Y1 - x (MoO4)4:xSm3+ phosphors. In the range from 300 K to 440 K, the samples have excellent thermal stability, and the fluorescence intensity is more than 96% higher than that at room temperature. The CIE chromaticity coordinates are located in the orange-red region. These results indicate that the Na5 Y1 - x (MoO4)4 - y (WO4)y: xSm3+ phosphor has potential value in WLED applications. [ABSTRACT FROM AUTHOR]

A series of Ca 3 Y 2 Ge 3 O 12 : xTb3+, yEu3+ (CYGO) phosphors were prepared by the high-temperature solid-phase reaction method. The physical phases, luminescence properties, and energy transfer of the samples were systematically analysed and discussed by XRD and fluorescence spectroscopy. Under the excitation at 377 nm, the CYGO: xTb3+ phosphor emits green light, and the concentration quenching point of Tb3+ ions is x = 0.24. The fluorescence intensity of Tb3+ ions decrease with the increase of the concentration of Eu3+ in CYGO: xTb3+, yEu3+ phosphors, the fluorescence intensity of Eu3+ ions increase rapidly, and the luminescence colour changes from green to red with the increasing of the concentration of Tb3+ at a certain concentration of Tb3+, the luminescence colour changes from green to red, confirm the existence of an energy transfer process between Tb3+ and Eu3+. The energy transfer mechanism is quadrupole-quadrupole interaction. The quantum yield is as high as 95.45%. Under the excitation of the UV-LED chip at 370 nm, the LED based on CYGO:0.24 Tb3+, 0.08Eu3+ phosphors have a R a of 86.7, low CCT of 4917 K and CIE coordinate of (0.3498,0.3789), so the CYGO: xTb3+, yEu3+ phosphors have a potential for application in the field of UV-near-UV white LEDs. has a certain application potential. [ABSTRACT FROM AUTHOR]

The various structural and conductive attributes of barium cerate, BaCeO3 position it as a highly promising matrix for energy storage purposes. The current study illustrates that barium cerate can be effectively tailored by introducing trivalent praseodymium ions, thereby enhancing its optical properties as well. In this work, single-phased orthorhombic crystalline powders of barium cerate incorporated with Pr3+ (BaCeO3: Pr3+) were synthesized using the gel combustion procedure, followed by calcination. We conducted a comprehensive investigation into their crystal structure, vibrational characteristics, optical properties, and potential applications in wLEDs. The structure refinement indicates that Pr3+ occupies Ce4+ site, which results in the expansion of the cell and facilitates the generation of defects such as Pr Ce ′ and oxygen vacancies V O ⋅ ⋅ . By correlating information gathered from diffuse reflectance spectra with that obtained from photoluminescence spectra, we gained a deeper understanding of the electronic level structure and the mechanism of energy transfer. We successfully achieved a finely tuned cool white light emission with very low color purity (CP), a high color rendering index (CRI), and a high correlated color temperature (CCT) with a quantum efficiency of 36.3 % by exciting the material with a 321 nm wavelength. Because of the transfer of energy within activators through dipole–dipole interaction, luminescence quenching occurs when Pr3+ concentration reaches 1 wt%. To the best of our knowledge, this is the initial investigation of luminescence properties of Pr-incorporated barium cerate perovskites. [ABSTRACT FROM AUTHOR]

Highly thermostable RhB@Zr-Eddc composites with the Rhodamine B (RhB) enclosed into the nanocages of Zr-Eddc was synthesized by one-pot method under hydrothermal conditions, whose structure, morphology and stability were characterized through the X-ray powder diffractometry (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). RhB@Zr-Eddc showed the highly thermal stability up to 550°C and emitted the bright red-light emission at 605 nm, which could highly selective detect the nitrofurazone (NFZ) among eleven other antibiotics in aqueous solution. Furthermore, via combining the RhB@Zr-Eddc with commercial green phosphor (Y3Al5O12:Ce3+, Ga3+), the mixture was encapsulated onto a 455 nm blue LED chip, creating an ex-cellent white light emitting diode (WLED) device with the correlated colour temperature (CCT) of 4710 K, luminous efficiency (LE) of 43.17 lm/w and Color Rendering Index (CRI) of 89.2.

We present double-perovskite molybdate with the formula of Ba2MgMoO6 doped with Sm3+ ions as a potential red phosphor to improve the color characteristics of white-light-emitting dioded (wLEDs). The new orange–red phosphor was synthesized using the co-precipitation (CP) method, and then its structural and spectroscopic properties were determined. Red emission at 642.6 nm dominates, which results from the electric dipole (ED) transition of the 4G5/2 → 6H9/2 type, and the materials are characterized by short luminescence decay times. BMM:Sm3+ is, to our best knowledge, the clearest example of dominant red emission of Sm3+ resulting from the location of the dopant in octahedral sites of high-symmetry cubic structure. In the sample containing 0.1% Sm3+, Sm3+ ions are located in both Mg2+ and Ba2+ sites, while at higher concentrations the Ba2+ site is less preferable for doping, as a result of which the emission becomes more uniform and single-site. The relative sensitivity calculated from FIR has a maximum of 2.7% K−1 at −30 °C and another local maximum of 1.6% K−1 at 75 °C. Such value is, to the best of our knowledge, one of the highest achieved for luminescent thermometry performed using only Sm3+ ions. To sum up, the obtained materials are good candidates as red phosphor to improve the color characteristics of wLEDs, obtaining a color-rendering index (CRI) of 91 and coordinated color temperature (CCT) of 2943 K, constituting a warm white emission. In addition to this, a promising precedent for temperature sensing using high-symmetry perovskite materials is the high sensitivity achieved, which results from the high symmetry of the BMM host. [ABSTRACT FROM AUTHOR]

To address the issue of the lack of red light in traditional Ce3+: YAG-encapsulated blue LED white light systems, we utilized spark plasma sintering (SPS) to prepare spinel-based Cr3+-doped red phosphor ceramics. Through phase and spectral analysis, the SPS-sintered ZnAl2O4: 0.5%Cr3+ phosphor ceramic exhibits good density, and Cr3+ is incorporated into [AlO6] octahedra as a red emitting center. We analyzed the reasons behind the narrow-band emission and millisecond-level lifetime of ZAO: 0.5%Cr3+, attributing it to the four-quadrupole interaction mechanism as determined through concentration quenching modeling. Additionally, we evaluated the thermal conductivity and thermal quenching performance of the ceramic. The weak electron-phonon coupling (EPC) effects and emission from antisite defects at 699 nm provide positive assistance in thermal quenching. At a high temperature of 150 °C, the thermal conductivity reaches up to 14 W·m−1·K−1, and the 687 nm PL intensity is maintained at around 70% of room temperature. Furthermore, the internal quantum efficiency (IQE) of ZAO: 0.5%Cr3+ phosphor ceramic can reach 78%. When encapsulated with Ce3+: YAG for a 450 nm blue LED, it compensates for the lack of red light, adjusts the color temperature, and improves the color rendering index (R9). This provides valuable insights for the study of white light emitting diodes (WLEDs). [ABSTRACT FROM AUTHOR]

AgInS2 quantum dots are an interesting material with a near-infrared band gap ranging from 1.87 to 1.98 eV. As a direct band gap semiconductor, it can adjust the band gap by adjusting the Ag/In ratio, and it also has a wide PL peak and a large Stokes shift. At the same time, the characteristics of low toxicity and environmental protection also make it an ideal material to replace binary quantum dots containing heavy metal elements such as Cd, Hg and Pb, and has a wide application prospect in the field of optoelectronic devices, especially in light emitting diodes. In this paper, the crystal structure and luminescence mechanism of AgInS2 quantum dots are described in detial, the characteristics of synthesis methods are summarized, and the strategies of regulating AgInS 2 quantum dots by shell engineering and doping methods are reviewed. Finally, the application progress of AgInS2 quantum dots in light-emitting diodes is introduced. [ABSTRACT FROM AUTHOR]

The study is dedicated to investigation of the structural, luminescent and photoconversion properties of epitaxial converters based on the single crystalline films of Ce3+ doped Ca3Sc2Si3O12 (CSSG:Ce) garnet. These SCFs with different thicknesses were grown using the liquid phase epitaxy method onto: (i) undoped Gd3Ga2.5Al2.5O12 (GAGG (2.5)) substrates; (ii) Ce3+ doped Gd3Ga2.5Al2.5O12 (GAGG:Ce (2.5) and Gd3Ga3Al2O12 (GAGG:Ce (3) substrates. For the first time, we have examined the phosphor conversion properties of the mentioned film and film-crystal converters under the excitation of a blue LED. We have established a trend line in the color coordinate diagram by systematically varying the film thickness in the 2–30 μm, 17–22 μm and 7–22 μm ranges for CSSG:Ce film/GAGG (2.5) crystal, CSSG:Ce film/GAGG:Ce (2.5) crystal and CSSG:Ce film/GAGG:Ce (3) crystal composite converters, respectively.

Eu3+,Dy3+ co‐doped Sr2LaZrO5.5‐based phosphors were prepared through a sol–gel method. Through characterization, it was found that the Sr2LaZrO5.5‐based fluorescent powder co‐doped with Eu3+ and Dy3+ had a cubic structure. At an excitation wavelength of 290 nm, the substrate Sr2LaZrO5.5 exhibited strong blue emission at 468 nm, and the Sr2LaZrO5.5:18%Eu3+ phosphor exhibited a strong red emission peak at 612 nm. When the doping amount of Dy3+ was 5, 8, 12, 15, or 18%, the Sr2LaZrO5.5:18%Eu3+ phosphor changed from an orange‐red light, to a warm white light, and to a cold white light. According to the emission spectra, the emission intensities of the substrates Sr2LaZrO5.5 and Sr2LaZrO5.5:Eu3+ decreased with increasing Dy3+ concentration, confirming the energy transfer between the host Sr2LaZrO5.5‐Eu3+,Dy3+, and resulting in a lower CCT value, with significantly improved white light emission. [ABSTRACT FROM AUTHOR]

Eco‐friendly lead‐free organic–inorganic manganese halides (OIMHs) have attracted considerable attention in various optoelectronic applications because of their superior optical properties and flexible solution processibility. Herein, we report a novel pseudo‐2D layered OIMH (MTP)2MnBr4 (MTP: methyltriphenylphosphonium), which exhibits intense green emission under UV/blue or X‐ray excitation, with a near‐unity photoluminescence quantum yield, high resistance to thermal quenching (I150 °C=84.1 %) and good photochemical stability. These features enable (MTP)2MnBr4 as an efficient green phosphor for blue‐converted white light‐emitting diodes, demonstrating a commercial‐level luminous efficiency of 101 lm W−1 and a wide color gamut of 116 % NTSC. Moreover, these (MTP)2MnBr4 crystals showcase outstanding X‐ray scintillation properties, delivering a light yield of 67000 photon MeV−1, a detection limit of 82.4 nGy s−1, and a competitive spatial resolution of 6.2 lp mm−1 for X‐ray imaging. This work presents a new avenue for the exploration of eco‐friendly luminescent OIMHs towards multifunctional light‐emitting applications. [ABSTRACT FROM AUTHOR]

Through employing the solid-state process under significant temperature, we produced a sequence of single-element radiation-adjustable phosphors Ca8MgR(PO4)7:Eu2+,Mn2+ or CaMg:EM (R = La, Y), and thoroughly analyzed the crystalline arrangement, photoluminescence (PL), PL excitation (PLE), as well as the degrading period. The findings suggest that Ca8MgLa(PO4)7:Eu2+,Mn2+ could be a green contender to be used within close ultraviolet-chip white light-emitted diode (WLED) devices. It is possible to change the emitting green hue from Ca8MgLa1-xYx(PO4)7 treated with Eu2+ to cyan by adjusting the La3+/Y3+ proportion for the purpose of lowering the crystal field potency. Furthermore, power shift among Eu2+ and Mn2+ would be used to create a conventional one-stage white CaMg:EM having a CIE hue coordinate shown as (0.330, 0.328). The power transmission process was shown in the form of resonant dipole-quadrupole nature. In addition, we also computed the critical range. The white-emitting single-composition CaMg:EM was effectively coated above one close ultraviolet chip under 375 nm, indicating that it may become a strong choice of phosphor within close ultraviolet WLED devices.

Given their potential utility in a variety of fields, including solid-state lighting, flat-panel displays, solar energy converters, optical amplifiers, and more, phosphors and glasses driven by Rare Earth (RE) ions and emitting multiple colors have attracted a lot of interest. Full-spectrum lighting, high-efficiency near-infrared emission, and wide colour gamut display are the primary difficulties for these emerging RE doped phosphors, which are dependent on the emission characteristics of the phosphors utilized. The various methods of synthesis for Eu3+ activated red emitting phosphors are discussed, with an emphasis on the aspects that contribute to improved luminous performance. This luminescence analysis is used in investing the Crystal structure and defects in metal oxides from which it provides information on the chemical and mechanical behavior of metal oxides during mining and processing operations. In this description, we outline the research findings and talk about the luminescence theory of the Eu3+ doped glasses and oxides for the red emission. [ABSTRACT FROM AUTHOR]

In recent years, all-inorganic cesium lead halide perovskite quantum dots have emerged as promising candidates for various optoelectronic applications, including sensors, light-emitting diodes, and solar cells, owing to their exceptional photoelectric properties. However, their commercial utilization has been limited by stability issues. In this study, we addressed this challenge by passivating the surface defects of CsPbBr3 quantum dots using indium acetate, a metal–organic compound. The resulting CsPbBr3 quantum dots exhibited not only high photoluminescence intensity, but also a remarkably narrow half-peak width of 19 nm. Furthermore, by embedding the CsPbBr3 quantum dots in ethylene-vinyl acetate, we achieved stretchability and significantly enhanced stability while preserving the original luminous intensity. The resulting composite film demonstrated the potential to improve the power conversion efficiency of crystalline silicon solar cells and enabled the creation of excellent white light-emitting diodes with coordinates of (0.33, 0.31). This co-passivation strategy, involving surface passivation and polymer packaging, provides a new idea for the practical application of CsPbBr3 quantum dots. [ABSTRACT FROM AUTHOR]

The red-emitting phosphor Sr2YNbO6: x Eu3+ and the orange-red-emitting phosphor Sr2YNbO6: y Sm3+ have been synthesized by the high-temperature solid-state method. All samples were thoroughly tested for phase purity, microscopic morphology, photoluminescence properties, thermal stability, and Commission Internationale de l'Eclairage (CIE) chromaticity coordinates. The results show that there is no impurity phase in the sample, the convergence factors are all less than 10%, the Eu3+ and Sm3+ ions participating in the mixed arrangement are consistent with the target doping concentration, and the microscopic particles are uniform and full. When the concentration of doped Eu3+ and Sm3+ reaches 0.25 mol and 0.02 mol, respectively, the luminous intensity is the best, and it emits red light at 610 nm and orange-red light at 606 nm under excitation at 467 nm and 406 nm, respectively. Dipole-dipole interactions are responsible for the concentration quenching. The quantum efficiencies (QE) are 68.95% and 53.91%, respectively. They all have excellent thermal stability with luminescence intensity at 425 K of 67.3% and 84.8% of room temperature, respectively. Color reproduction (Ra) and comfortable color rendering index (R9). Ra reached 91 and 88, respectively, and R9 reached 73.4 and 65.8, respectively, for the combined white light-emitting diode (WLED) prepared with commercial phosphors and experimental samples. All the results suggest that Sr2YNbO6: RE (Eu3+, Sm3+) can be used as a red phosphor replacements in WLEDs. [ABSTRACT FROM AUTHOR]

The cyan-emitting BaSi 2 O 2 N 2 :Eu2+ phosphor is a promising narrow-band and high-efficiency luminescent material used in wide-color-gamut white light-emitting diodes (wLEDs). However, its serious degradation under thermal attacks hinders its practical applications and needs to be improved. Herein, we proposed to deposit a nano-sized Al 2 O 3 film around each BaSi 2 O 2 N 2 :Eu2+ particle through atomic layer deposition (ALD) in a fluidized bed reactor to improve its thermal stability. Thermal gravimetric analysis results showed that the Al 2 O 3 layer with a thickness of only 11 nm had an obvious anti-oxidization effect, by which the oxidation temperature in air of the Al 2 O 3 coated phosphor was largely increased from ∼550 to ∼750 °C. Moreover, the Al 2 O 3 coated phosphor remained 93% of its luminescence intensity in comparison to 73% of the uncoated one when degraded under water-steam at 200 °C for 24 h. The oxidization of both the BaSi 2 O 2 N 2 host matrix and the doped Eu2+ ions was reduced by the Al 2 O 3 layer. Meanwhile, the wLEDs fabricated with the Al 2 O 3 coated phosphor showed a luminous flux of 3 times higher than that of the uncoated one when aged under 100 mA for 300 h. The greatly improved thermal degradation property of BaSi 2 O 2 N 2 :Eu2+ phosphor and the reliability of the wLEDs indicate that the ALD approach could be a feasible route to produce uniform and nano layers on phosphors and enhance their stability. [ABSTRACT FROM AUTHOR]

ZnO nanoparticles doped with Co at different concentration (Zn1−xCoxO) were synthesized by sol–gel auto combustion method and are characterized by using various characterization tools. Structural study using X-ray diffraction technique (XRD) analysis showed the crystalline nature with hexagonal wurtzite geometry and the composition analysis using energy dispersive X-ray spectroscopy (EDX) confirmed the incorporation of Co in the ZnO lattice in the case of doped nanoparticles. Scanning electron-microscopy (SEM) and transmission electron microscopy (TEM) analysis showed the prepared nanoparticles as spherical, loosely agglomerated and having dimension of nanoscale. UV–vis DRS studies indicated a red shift in optical band gap with Co doping. PL spectra exhibits emission in the UV and visible region and the analysis revealed information about the presence of various types of defects in the ZnO lattice. An increase in the excitation wavelength gives intense emission in the high wavelength region for doped nanoparticles confirming the presence of divalent and monovalent oxygen as main defects. The Zn0.93Co0.07O nanoparticles records CIE coordinates lying in the white region of CIE color space at 350 nm with CCT of 5561.4 K suggesting their suitability in fabrication of white light emitting diodes. [ABSTRACT FROM AUTHOR]

The tunable 5 d-4f luminescence of Eu2+ is of great application value, but it is still full of challenges in terms of luminescence efficiency, thermal stability and precise tuning of luminescence colors. In this work, we synthesized a series of Rb 2-x Cs x CaP 2 O 7 :0.015Eu2+ phosphors based on the equivalent substitution strategy, allowing a certain proportion of Cs+ to replace Rb+ sites. By optimizing the Rb/Cs ratio, the structural symmetry of the [CaO 6 ] octahedra can be enhanced, providing a high-stability and high-symmetry localized crystal field environment for the high efficiency luminescence of Eu2+. The experimental results confirmed that the broad-spectrum orange light emission could be achieved in Rb 0·5 Cs 1·5 CaP 2 O 7 :0.015Eu2+, and the integrated luminescence intensity was 6.9 times higher than that of Rb 2 CaP 2 O 7 :0.015Eu2+. Moreover, the luminescence intensity at 150 °C reached 93.3% of its room-temperature value. Using the synthesized phosphor as orange component, a white LED was assembled and a high-quality white light emission with Ra = 87.8 was achieved. These results suggest that rationally tuning the local structural symmetry around Eu2+ is an effective strategy to develop high-performance Eu2+-activated phosphors. [ABSTRACT FROM AUTHOR]