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The optical‐magnetic multifunctional materials are of great importance owing to their potential applications in intersect discipline fields. However, the multifunctional materials with satisfied optical and magnetic property are limited, and the modulation mechanism of their magneto‐optical property related to their structure feature is ambiguous. Here, a new multifunctional solid solution phosphors Ca18K3Sc1‐xSmx(PO4)14 (0 ≤ x ≤ 1) are designed based on composition engineering and are successfully synthesized. The detailed structure feature including the structural evolution of the crystallographic parameters and local lattice environment as well as polyhedral distortion behavior are investigated through X‐ray diffraction Rietveld structure refinement for Ca18K3Sc1‐xSmx(PO4)14 in the full range (0 ≤ x ≤ 1). The photoluminescence spectra indicate that Ca18K3Sc1‐xSmx(PO4)14 (0 ≤ x ≤ 1) can emit intense orange‐red emission (IQE~42.6%) under ultraviolet light excitation ascribed to the4G5/2 ‐6H7/2 transition of Sm3+ ions. The structure modulated luminescence behavior, for example, the tunable emission ratio of I648/I565, high quenching content, and electric multipole interaction mechanism are studied. The versatile phosphors can exhibit tunable orange‐red cathodoluminescence emission along with increasing the accelerating voltage. The electron transition mechanism of the photoluminescence and cathodoluminescence behavior is further discussed through a simple schematic diagram. Moreover, Ca18K3Sc1‐xSmx(PO4)14 (0 ≤ x ≤ 1) shows a ferromagnetic behavior with controllable magnetization and coercive field. Finally, the impact of Fe ions on the photoluminescence and magnetic property of Ca18K3Sc1‐yFey(PO4)14: 0.4Sm3+ (0 ≤ y ≤ 0.05 and y = 1) phosphors are investigated. The current research can provide some ideas and mechanism to design and investigate more novel magneto‐optical muntifunctional materials for versatile applications in intersect disciplines. [ABSTRACT FROM AUTHOR]

A series of rare earth ions doped novel niobate phosphors SrBaNb 4 O 12 :Re3+ (Re= Eu, Dy, Sm and Pr) were successfully developed through solid state reaction. The phase composition and morphology were investigated through X-ray structure refinement, scanning electron microscopy and energy dispersive spectrometer. The layered crystal structure of SrBaNb 4 O 12 and the local lattice environment of Re3+ were discussed in detail. The electronic structure property and density of states were calculated based on density functional theory. To investigate the characteristic luminescence property, the excitation and emission spectra, fluorescence lifetimes and Commission Internationale de l'E′clairage (CIE) chromaticity index of SrBaNb 4 O 12 :Re3+ (Re= Eu, Dy, Sm and Pr) series phosphors were determined as well. [ABSTRACT FROM AUTHOR]

An intense emission green color phosphor of Al-doped Ba1.98SiO4:0.02Eu2+ synthesized with different Si3N4/SiO2 ratio was prepared by conventional sintering method. The X-ray diffraction patterns, the photoluminescence, scanning micrograph and thermal quenching properties of Ba1.98SiO4:0.02Eu2+ with different Si3N4/SiO2 ratio were investigated in detail. As the Si3N4/SiO2 ratio increases, the emission intensity enhanced gradually until the optimum Si3N4/SiO2 ratio reached 3/2. The PL intensity with Si3N4/SiO2 = 3/2 is about four times of the initial intensity of Ba1.98SiO4:0.02Eu2+ phosphor and the reason was discussed clearly. Furthermore, when we introduced Al3+ ions into the host, the samples exhibited outstanding optical properties and smaller thermal quenching behavior compared with Ba1.98SiO4:0.02Eu2+ phosphor. The emission intensity of Ba1.98Si1−xAlxO4:0.02Eu2+ series increased until x reached 7% and the emission intensity of x = 0.07 is 5 times of the originated intensity of Ba1.98SiO4:0.02Eu2+ synthesized without Si3N4. The smaller thermal quenching behavior of Al-doped phosphors was studied clearly, too. All the results suggested that Al-doped Ba1.98SiO4:0.02Eu2+ phosphor synthesized with Si3N4/SiO2 = 3/2 can be a candidate green phosphor for WLEDs. [ABSTRACT FROM AUTHOR]

Abstract: Hydrothermal reaction at 150°C and pH = 10 for 24 hours crystallized (Gd,RE)2(OH)4SO4 layered hydroxide sulfate (monoclinic structure; RE = Pr, Tb), from which Gd2O2S:RE (hexagonal structure) green phosphor hexagons were derived via facile dehydration in flowing H2 at 1200°C. Rietveld refinement of the XRD patterns yielded cell dimensions that confirmed the direct crystallization of solid solution. Photoluminescence (PL) study at room temperature found absolute quantum yields of ~25.1% and 28.4%, CIE chromaticity coordinates of (0.145, 0.679) and (0.326, 0.566), and fluorescence lifetimes of ~2.36 μs and 1.21 ms for Pr3+ and Tb3+ under 300 and 275 nm UV excitations, respectively. Temperature‐dependent PL analysis (25‐200°C) indicated that both the Pr3+‐ and Tb3+‐doped phosphors have favorably good thermal stability and retained ~65% and 80% at 100°C and ~41% and 47% at 200°C of their initial emission intensities, respectively. The activation energy for the thermal quenching of PL was determined to be ~0.221 (Pr3+) and 0.314 eV (Tb3+). Cathodoluminescence (CL) found that both the phosphors exhibit increasingly higher emission intensity/brightness at a higher acceleration voltage (up to 7 kV) or beam current (up to 50 μA) and are stable under electron bombardment in the studied range. Raising beam current was suggested to be more effective to enhance CL. [ABSTRACT FROM AUTHOR]

To explore a new family of phosphate phosphors for application in ultraviolet-based light emitting diodes (LEDs), novel promising blue emission solid solution phosphors, Ca1−xSrxHf4(PO4)6:Eu2+, with efficient and controllable photoluminescence were synthesized and characterized in the full range of 0 ≤x≤ 1. To deeply understand the relationship between the structure and properties of the phosphors, the phase purities, crystal structures and linear structural evolutions of Ca1−xSrxHf4(PO4)6:Eu2+ solid solutions were investigated in detail by FT-IR spectroscopy and Rietveld structure refinement of their powder XRD patterns and verified by high transmission electron microscopy (HRTEM). The linear structural evolutions induced controllable blue emission with high quantum efficiency and excellent thermal stability in the Ca1−xSrxHf4(PO4)6:Eu2+ solid-solution phosphors. Moreover, the photoluminescence properties in Ca1−xSrxHf4(PO4)6:Eu2+ can be optimized by adjusting the components. The mechanism of the controllable luminescence properties was also investigated in detail. Excellent thermal stability was obtained in Ca1−xSrxHf4(PO4)6:Eu2+, and the thermal quenching mechanism was investigated. Finally, white LEDs were fabricated and their electroluminescence properties were investigated. This simple and effective method to optimize the photoluminescence properties of phosphors can be used for designing other novel solid-solution phosphors. [ABSTRACT FROM AUTHOR]

Pr 3+ activated niobate phosphors Ba 3- x ZrNb 4 O 15 : x Pr 3+ were firstly synthesized through high temperature solid-state method. The phase purity, crystal structure, morphology, luminescence property as well as thermal quenching behavior were carefully determined by using X-ray diffractometer, scanned electron microscope, photoluminescence and temperature dependent emission spectra, respectively. The luminescent property showed that Ba 3- x ZrNb 4 O 15 : x Pr 3+ (0.002 ≤  x  ≤ 0.03) had dominate excitation around 451 nm and could exhibit red emissions peaking at 608, 618 and 651 nm, attributed to the 1 D 2 - 3 H 4 , 3 P 0 - 3 H 6 and P 0 - 3 F 2 transitions of Pr 3+ ions. The different concentration quenching behaviors were found while the related mechanism was investigated. The room temperature decay times and the related fluorescence dynamics process of Pr 3+ ions in Ba 3 ZrNb 4 O 15 were investigated. In addition, the optimal doping contents, CIE chromaticity coordinates as well as the color purity were determined. At last, the temperature sensitive emission quenching and decay behavior were discussed and the activation energy was calculated based on Arrhenius equation. [ABSTRACT FROM AUTHOR]

Sm3+ activated barium hafnium phosphate phosphor Ba7Hf(PO4)6:Sm3+ with excellent thermal stability was firstly prepared with solid-state reaction method. The phase purity, luminescence property and thermal stability were systematically determined by employing X-ray diffractometer, photoluminescence spectra and temperature dependent emission spectra. The photoluminescence emission spectra showed that Ba7Hf(PO4)6:xSm3+ (0.005 ≤ x ≤ 0.04) could absorb near-ultraviolet light around 402 nm and emit red emissions with dominating peaks at 598 and 645 nm, ascribed to the 4G5/2 to 6H7/2 and 6H9/2 transitions of Sm3+ ions. The optimal doping contents as well as the Commission Internationale de L’Eclairage chromaticity coordinates of Ba7Hf(PO4)6:Sm3+ were studied. The interesting blue emission band at about 475 nm was observed and the related mechanism was discussed. The temperature dependent emission spectra revealed that Ba7Hf(PO4)6:xSm3+ exhibited stable thermal quenching behavior. The results showed that the red phosphors Ba7Hf(PO4)6:Sm3+ had potential applications in white light emitting diodes. [ABSTRACT FROM AUTHOR]

A series of novel red emission phosphors NaMgZr(PO):Eu was synthesized by solid state reaction. The phase purity, crystal structure of NaMgZr(PO) host and the site occupancy behaviour of Eu were investigated through X-ray diffraction refinement and series X-ray diffraction patterns analysis. The structure and temperature related luminescence properties were studied in detail by photoluminescence excitation, emission spectra and decay times. Upon 393 nm excitation, NaMgZr(PO):Eu phosphor can exhibit strong red emission dominated at 611 nm (D-F transitions) with excellent thermal stability. The thermal stability property and the quenching mechanism were investigated. The observed abnormal transitions from D energy level were discussed. The results indicated that NaMgZr(PO):Eu could be a suitable red-emitting phosphor candidate for white light emitting diodes. [ABSTRACT FROM AUTHOR]

A series of SrEuMgSiN:Eu nitride phosphors were synthesized by gas-pressed sintering method. X-ray diffraction with Rietveld refinements, photoluminescence spectra, thermal quenching behavior, and lifetimes were utilized to characterize samples. The influence of incorporating Mg into SrSiN:Eu phosphors on the crystal structure and luminescence properties were discussed in detail. At a certain concentration, doping Mg can greatly enhance the PL intensity of SrSiN:Eu phosphors. The red phosphor SrEuMgSiN:Eu exhibited a small thermal quenching, which remained 75% of the initial emission intensity when measured at 150 °C. All the results indicate that the SrEuMgSiN:Eu can be an excellent candidate of phosphor applicable to n-UV LEDs for solid-state lighting. [ABSTRACT FROM AUTHOR]

RbZnPO 4 : x Sm 3+ (0.005 ≤ x ≤ 0.05) red phosphors were prepared for the first time. The phase purity, luminescence property and thermal stability were systematically determined by employing X-ray diffractometer, excitation and emission spectra and temperature dependent emission spectra. The site occupation of Sm 3+ in RbZnPO 4 was discussed based on the X-ray diffractometer analysis. The electronic structure property of RbZnPO 4 host was studied, which revealed that RbZnPO 4 possessed a direct band gap with band gap value of 3.815 eV. The photoluminescence emission spectra showed that RbZnPO 4 : x Sm 3+ (0.005 ≤ x ≤ 0.05) could absorb near-ultraviolet light around 404 nm and emit red emissions with dominated peaks at 601 and 647 nm, ascribed to the 4 G 5/2 to 6 H 7/2 and 6 H 9/2 transitions of Sm 3+ ions, respectively. The optimal doping concentration and the critical distance as well as the interaction mechanism of Sm 3+ in RbZnPO 4 were discussed. The interesting temperature sensitive thermal quenching behavior and the related mechanism were studied. [ABSTRACT FROM AUTHOR]

A series of versatile phosphors Sr 10 [(PO 4 ) 5.5 (BO 4 ) 0.5 ](BO 2 ):Sb 3+ /Eu 3+ /Pr 3+ /Dy 3+ were firstly synthesized by solid-state method. The phase purity was analyzed through X-ray diffraction and their characteristic luminescence properties were investigated. The results showed that Sr 10 [(PO 4 ) 5.5 (BO 4 ) 0.5 ](BO 2 ): Sb 3+ exhibited broad blue emission centered at 459 and 467 nm, due to the selective excitation transitions ( 3 P 1/0 → 1 S 0 ) of Sb 3+ occupying different crystal sites in Sr 10 [(PO 4 ) 5.5 (BO 4 ) 0.5 ](BO 2 ). The emission spectrum of Sr 10 [(PO 4 ) 5.5 (BO 4 ) 0.5 ](BO 2 ): Eu 3+ consisted of a series of lines attributed to the 5 D 0 → 7 F J ( J =1, 2, 3, 4) transitions of Eu 3+ . Moreover, an unusual blue emission band was observed, which was discussed in detail and proved to be related to the vacancy of Sr 2+ through the charge compensation mechanism. In addition, red and warm white emissions could be obtained from Pr 3+ and Dy 3+ single doped Sr 10 [(PO 4 ) 5.5 (BO 4 ) 0.5 ](BO 2 ) and their luminescence properties were discussed, respectively. [ABSTRACT FROM AUTHOR]

A novel Pr 3+ ions doped red phosphor Ca 19 Mg 2 (PO 4 ) 14 :Pr 3+ was first synthesized and the phase purity as well as the characteristic photoluminescence property was investigated through X-ray diffraction, diffuse-reflectance and photoluminescence spectra measurement. The analysis revealed that Ca 19 Mg 2 (PO 4 ) 14 :Pr 3+ had strong absorption from 450 to 470 nm and could exhibit red emission peaking around 610 nm under 450 nm excitation. The emission quenching behavior of 1 D 2 – 3 H 4 transitions via increasing the Pr 3+ contents was investigated and the mechanism was discussed in detail. The temperature dependent emission spectra of Ca 19 Mg 2 (PO 4 ) 14 : x Pr 3+ with different doping contents ( x =0.002 and x =0.02) were studied and the abnormal thermal quenching property was investigated. [ABSTRACT FROM AUTHOR]

A novel phosphate RbZnPO4 has been developed for the first time and the characteristic crystal structure of RbZnPO4 has been investigated in detail, based on the Fourier transform infrared reflection spectra and the structure refinement of X-ray diffraction data. After doping with Eu3+,RbZnPO4:Eu3+ shows distinctive deep red emission with dominating peaks at 596 and 701 nm. To provide a reasonable explanation for the relationship between photoluminescence and structure, the photoluminescence property has been discussed by analyzing the particular local ligand environment and site occupation of Eu3+ in RbZnPO4. More interestingly, temperature-sensitive emission behavior was found in RbZnPO4:Eu3+. Through the synthetical analysis of the configurational coordinate diagram, the charge compensation experiment and the CASTEP band structure calculation, a complex underlying mechanism is proposed to explain the abnormal temperature-sensitive emission behavior in RbZnPO4:Eu3+. The mechanism could be helpful for better understanding the thermal quenching process of Eu3+ in RbZnPO4 and also as a reference in some other temperature-sensitive phosphors. [ABSTRACT FROM AUTHOR]

The promising green oxynitride phosphor, Ba3−xMgxSi6O12N2:Eu2+ was synthesized by the solid-state reaction method. The effect of Mg2+ doping on the structure and photoluminescence (PL) properties of Ba3Si6O12N2:Eu2+ was investigated systematically. The results reveal that the phosphor retains the single phase of Ba3Si6O12N2, with the lattice expanding upon increasing the Mg2+ concentration, in an appropriate range. This suggests that a large portion of Mg2+ enters into the interstitial sites of the crystal lattice. At a certain concentration, Mg2+ doping can greatly enhance the absorption and PL intensity and decrease the full widths at half maximum (FWHM) of Ba3Si6O12N2:Eu2+ phosphors. The green phosphor Ba2.87Eu0.1Mg0.03Si6O12N2 exhibited a small thermal quenching, which remained 82% of the initial emission intensity when measured at 150 °C. The quantum efficiency measured at 400 nm excitation was 38.5%. All the results indicate that the solid solution Ba3−xMgxSi6O12N2:Eu2+ can be a good candidate for phosphors applicable in n-UV LEDs for solid-state lighting. [ABSTRACT FROM AUTHOR]

A novel phosphate Ca9La(GeO4)0.75(PO4)6 was investigated to add to the family of phosphate phosphors and application in LEDs. In this work, the single phase red-emission Ce3+,Mn2+ co-doped phosphate Ca9La(GeO4)0.75(PO4)6 phosphor was synthesized by the solid-state reaction from both theoretical and practical points of view. The crystal structure was determined by Rietveld refinement and TEM. Its cell parameters are a = b = 10.4077605(2) Å, and c = 37.4714968(1) Å. The characteristic photoluminescence properties were studied in detail using photoluminescence excitation spectra, emission spectra, decay times and thermal quenching properties. Purple and red broad band emission from Ce3+ and Mn2+ was detected under excitation at 313 nm. According to this research, the Ca9La(GeO4)0.75(PO4)6:Ce3+,Mn2+ phosphor shows high thermal stability in the red-emission area. With the increase of the temperature, the intensity ratio of Mn2+ and Ce3+ emission rises rapidly and the purity of red-emission is improved. In order to reasonably explain this special phenomenon, an implicit mechanism between thermal quenching and energy transfer is proposed based on the configurational coordinate diagram. In addition, the mechanism could be helpful for understanding the thermal properties of multiple activators Ce3+ and Mn2+ co-doped phosphors as the reference. [ABSTRACT FROM AUTHOR]

A series of Pr 3+ activated Y 2 WO 6 phosphors are prepared by solid state reaction method. The crystalline phase and luminescent properties of samples are discussed by X-ray diffraction spectra and photoluminescence spectra, respectively. The photoluminescence excitation spectrum indicates that the sample can absorb both UV and blue light. And the samples emit a blue emission of WO 6 6 − and the characteristic red emission of Pr 3+ . The partial quenching of the other prominent blue luminescence from 3 P 0 state is ascribed to a radiationless relaxation pathway involving a low-lying Pr 4+ –W 5+ intervalence charge transfer (IVCT) state. Through adjusting the excitation wavelength, Y 2 WO 6 : Pr 3+ can not only emit warm white light with CIE coordinates of (0.33, 0.37) but also show bright red emission with CIE coordinates of (0.66, 0.33). In addition, the thermal properties of the samples are also investigated in detail. The results show that the application as a white and red component for white light emitting diodes is proposed. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel red phosphor Ca19Mg2(PO4)14:Sm3+ was synthesized and investigated firstly. [•] The structure and characteristic luminescence properties are discussed. [•] The excellent thermal stability was found and investigated. [•] It has good color saturation, the CIE is close to that of commercial Y2O3:Eu3+. [Copyright &y& Elsevier]

Abstract: Eu3+ doped NaSr2Nb5O15 series were firstly synthesized by solid-state reaction method. Crystal structure, characteristic luminescence properties as well as charge compensation mechanism are investigated detailedly by X-ray diffraction refinement and photoluminescence spectra measurement. NaSr2Nb5O15:Eu3+ exhibits strong absorption in near ultraviolet-blue region and intense red emission with CIE chromaticity coordinates (0.638, 0.355) after adding the charge compensation agent upon 398nm excitation. The integral intensity of NSN:0.03Eu3+, 0.03Li+ is 64.5% of the commercial Y2O3:Eu3+ and the quantum efficiency is calculated to be 41.5%. The results show that NaSr2Nb5O15:Eu3+ can be a promising red-emitting phosphor for white LEDs. [Copyright &y& Elsevier]

A new chlorogermanate compound Ca8 Mg( GeO4)4 Cl2 ( CMGC) was synthesized via high-temperature solid-state reaction for the first time. The crystal structure of CMGC had been refined and determined from the XRD profiles by Rietveld refinement method, which belong to space group Fd-3 m with the lattice constants a = b = c = 15.1760(25) Å. Photoluminescence properties of CMGC: Eu2+ phosphors were investigated by absorption spectra, excitation, and emission spectra. The occupy situation and energy transfer were investigated by decay lifetimes and emission spectra under different excitation wavelengths. Thermal stability was also measured. The results show that the absorption spectra of CMGC: Eu2+ phosphors cover from 250 to 500 nm. Under 365 and 435 nm excitation, the emission spectra of CMGC: Eu2+ phosphors show blue-green (centered at 425 and 510 nm) and green (centered at 510 nm) emission, respectively, which attributed to Eu2+ ions occupying different crystal sites. Our results indicated that CMGC: Eu2+ phosphors had a potential application use for white light-emitting diodes. [ABSTRACT FROM AUTHOR]

In the frame of exploring suitable yellow emission phosphors for blue light pumped high power warm LEDs, RbZnPO4:xDy3+ (x = 0-0.05) is investigated by powder XRD refinement and photoluminescence spectroscopy. [ABSTRACT FROM AUTHOR]

Rare-earth (RE) doped AlN are excellent candidate materials for electroluminescent devices, full color displays and white lighting technology. In this paper, a deep red Sm2+ doped AlN (AlN:Sm2+) phosphor was synthesized for the first time by a one-step direct nitridation method. Detailed XRD and EDS studies show the presence of samarium (Sm) ions the AlN, and XPS measurements indicate Sm ions are divalent. SEM and TEM studies show that the AlN:Sm2+ have a branched nanostructure, consisting of a primary stem and secondary short nano-branches. AlN:Sm2+ phosphor has a broad and strong excitation bands in the range of 300–600 nm, ultra-narrow deep red emission at 686 nm, near unity color purity, and good thermal stability (78.2% at 413 K). A blue-pumped warm white light emitting diode with high color rendering index (Ra∼87.5) and low correlated color temperature (CCT∼4875 K) was fabricated. Moreover, a super-wide color gamut (117.6% of the NTSC) can be achieved by using AlN:Sm2+ as the red component. Furthermore, photoluminescence (PL) and Raman spectra of AlN:Sm2+ were studied under hydrostatic pressure up to 25 GPa. The shift of the 5D 0 →7F 0 emission band (dλ/dP≈0.13 nm/GPa) and the decrease of PL intensity ratio (5D 0 →7F 0 /5D 0 →7F 1 , dI R (0/1)/dP≈−5.6%/GPa) with applied pressure can be used for optical pressure sensor. Raman spectroscopy revealed a phase transition of AlN:Sm2+ from wurtzite to rocksalt phase at 19.9 GPa. The large doping of Sm2+ ions and unique intrinsic geometry in branched nanostructure co-affect its compressibility and structural stability under high pressure. The results indicate that AlN:Sm2+ phosphor has promising applications in backlight displays and optical pressure sensors due to their excellent luminescent properties. [ABSTRACT FROM AUTHOR]

NaLa9(GeO4)6O2:xEu3+ (x = 0-0.11) phosphors are prepared by firing a stoichiometric mixture of Na2CO3, La2O3, Eu2O3, and GeO2 in air (1. [ABSTRACT FROM AUTHOR]

Highly ordered porous silicon array (PSA) films were fabricated by anodic oxidation of p-type silicon wafer. Using the methods of magnetron sputtering and thermal annealing, dispersed TiO 2 nanoparticles (NPs) were decorated onto the top of PSA films. Steady-state photoluminescence (PL) spectra and nanosecond time-resolved transient photoluminescence (NTRT-PL) spectra of as-fabricated nano-composites were studied under light irradiation with wavelengths of 266 nm and 400 nm, respectively. A distinct blue-shift in the NTRT-PL spectra is observed owing to the presence of Si 3+ and Ti 3+ cations, which is further confirmed by X-ray photoelectron spectroscopy (XPS). Such a phenomenon could be well explained by considering the competition mechanism between the photo-generated charge separation process and recombination associated with oxygen vacancy (OV). Our present research demonstrates a novel approach to investigate charge separation and transport in a dual-band gap photoelectrochemical (PEC) system. Following this scheme, UV and visible-light photocatalytic activities of TiO 2 /PSA heterojunction composites were evaluated through photodegradation of methyl orange (MO) in aqueous solution. Our current work is expected to provide a simple strategy for synthesising composite photocatalysts, with the hope that optimal sunlight harvesting would be achieved. [ABSTRACT FROM AUTHOR]

A novel phosphate RbZnPO4 has been developed for the first time and the characteristic crystal structure of RbZnPO4 has been investigated in detail, based on the Fourier transform infrared reflection spectra and the structure refinement of X-ray diffraction data. After doping with Eu3+,RbZnPO4:Eu3+ shows distinctive deep red emission with dominating peaks at 596 and 701 nm. To provide a reasonable explanation for the relationship between photoluminescence and structure, the photoluminescence property has been discussed by analyzing the particular local ligand environment and site occupation of Eu3+ in RbZnPO4. More interestingly, temperature-sensitive emission behavior was found in RbZnPO4:Eu3+. Through the synthetical analysis of the configurational coordinate diagram, the charge compensation experiment and the CASTEP band structure calculation, a complex underlying mechanism is proposed to explain the abnormal temperature-sensitive emission behavior in RbZnPO4:Eu3+. The mechanism could be helpful for better understanding the thermal quenching process of Eu3+ in RbZnPO4 and also as a reference in some other temperature-sensitive phosphors. [ABSTRACT FROM AUTHOR]

Abstract: The photoluminescence properties of mono Ce3+ doped Sr5(PO4)2SiO4 (SPS) apatite phosphors, prepared via a solid-state reaction at high temperature, were investigated in the ultraviolet region. The white light can be realized by adjusting the contents of activator Ce3+ or the excitation wavelength. Upon 365nm excitation, SPS: 0.05Ce3+ shows bright white light (34.74% of YAG) with CIE color coordinates of (0.33, 0.34), a superior color-rendering index of 90 and correlated color temperature of 5603K, suitable for potential use based on 365nm UV-InGaN chip. [Copyright &y& Elsevier]

Abstract: The photoluminescence properties of Si–N doped BaMgAl10O17:Eu2+, Mn2+ phosphors were studied. Photoluminescence spectrum, powder X-ray diffraction and decay curves were used. The electronic structure of un-doped BaMgAl10O17 was investigated by using the density functional theory. It reveals that an ideal hexagonal shape and particle size in 3–5μm are obtained by Si–N doping. Additionally, its photoluminescence and thermal stability are both improved. The energy transfer from Eu2+ to Mn2+ also enhanced by suitable Si–N doping. These are expected to be potentially applicable to industrial production of the phosphor in plasma display panels. [Copyright &y& Elsevier]

A novel borate mineral of Ba 3 Sc 1.9 Al 0.1 B 4 O 12 was synthesized successfully by traditional high temperature solid-state reaction. Its structure is determined by High-resolution transmission electron microscopy, Energy Dispersive X-Ray Spectroscopy and X-ray powder diffraction Rietveld refinement. The crystal structure of Ba 3 Sc 1.9 Al 0.1 B 4 O 12 was found to be trigonal crystal system and the space group is attributed to P-3m1 (164). Moreover, a series of Eu2+ doped Ba 3 Sc 1.9 Al 0.1 B 4 O 12 phosphors are investigated. The electron structure, band structure and photoluminescence properties of Ba 3 Sc 1.9 Al 0.1 B 4 O 12 : Eu2+ are investigated in detail by density functional theory calculations, diffuse reflection spectra, emission-excitation spectra, decay curves and temperature dependence spectra. It can emit orange light peaking at ∼592 nm upon 400 nm NUV excitation with quantum efficiency 40.1%. According to structure and photoluminescence (PL) properties analysis, Eu2+ can occupy two kinds of Ba2+ site. The concentration quenching mechanism of Eu2+ could be a d-d interaction luminescence center. It has not good temperature stability properties because of too much temperature-dependent electron–phonon interaction at high temperature. The fabricated white-LEDs using a 370 nm GaN NUV chip combined with orange/blue phosphors under different weight ratio driven by 30 mA current can get series warm-white light, which the correlated color temperature is smaller than 'YAG + Blue chips' It demonstrates that Ba 3 Sc 1.9 Al 0.1 B 4 O 12 : Eu2+ is a potential orange phosphor matching NUV LED chips to get warm white light. • A novel orange emission (592 nm) phosphor Ba 3 Sc 1.9 Al 0.1 B 4 O 12 : Eu2+ excited by NUV light was synthesized successfully. [ABSTRACT FROM AUTHOR]

Abstract A series of new red emission phosphors Ca 7 Zn 2 (PO 4) 6 : Re3+ (Re3+ = Eu3+, Sm3+, Pr3+) are synthesized by solid state reaction. The crystal structure and microstructure are systematically investigated by X-ray diffraction Rietveld structure refinement, scanning electron microscopy and energy dispersive spectrometer. The photoluminescence properties of Ca 7 Zn 2 (PO 4) 6 : Re3+ (Re3+ = Eu3+, Sm3+, Pr3+) are studied in detail. The results show that Eu3+, Sm3+ or Pr3+ single doped Ca 7 Zn 2 (PO 4) 6 could emit red emissions with dominate peaks at 612 nm, 602 nm and 612 nm, respectively, which are attributed to the characteristic transitions (5D 0 -7F 2 , 4G 5/2 -6H 7/2 and 3P 0 -3H 6) of Eu3+, Sm3+ and Pr3+. The concentration dependent emission spectra of Ca 7 Zn 2 (PO 4) 6 : Sm3+ are studied as well. A charge compensator Li 2 CO 3 is added in Sm3+ doped Ca 7 Zn 2 (PO 4) 6 and the emission intensity is compared with the commercial red phosphor Y 2 O 3 :Eu3+. The room temperature fluorescence lifetimes of Ca 7 Zn 2 (PO 4) 6 : Re3+ (Re3+ = Eu3+, Sm3+, Pr3+) are measured and the average lifetimes are evaluated. Finally, the Commission Internationale de L'Eclairage chromaticity coordinates and their color purity are calculated. Graphical abstract Image 1062 Highlights • Novel red emission phosphors CZP: Re3+ were synthesized for the first time. • Phase purity and microstructure were examined by XRD, SEM and EDS. • Characteristic luminescent property of CZP: Re3+ was investigated. • The detailed emission property of CZP:Sm3+ and CZP:Sm3+, Li+ was studied. • Decay behavior, CIE and color purity of CZP: Re3+ were investigated. [ABSTRACT FROM AUTHOR]

Abstract Cerium doped aluminum nitride (AlN:Ce) hierarchical nanostructures were fabricated by a direct reaction of Al and CeO 2 mixed ingot with ammonia using modified arc discharge method. X-ray diffractometry, Raman spectrum and x-ray photoelectron spectroscopy analysis obviously indicated that Ce3+ ions incorporated inside the AlN nanostructures. The prepared AlN:Ce exhibited a strong red-orange emission at 600 nm and showed room temperature ferromagnetism. These results suggest that AlN:Ce hierarchical nanostructures have potential as a light-emission nanodevice and diluted magnetic semiconductor. Highlights • Ce was incorporated in AlN forming hierarchical nanostructures. • The Ce doped AlN exhibited an intensive PL emission band at 600 nm. • The AlN:Ce nanostructures exhibited room ferromagnetism. [ABSTRACT FROM AUTHOR]

Cyan phosphors with high efficiency and excellent thermal stability are an important part for application in full spectrum illumination. Herein, a series of nitriding cyan emission phosphors Ca 2 (Y, Ce)Hf 2 (Al, Si) 3 (O, N) 12 with garnet structure are successfully synthesized. Their phase purity, crystal structure, morphology, elemental composition and valence state are analyzed in detail, and the results indicate that a small amount of Si 3 N 4 doping does not cause impurity phase. The phosphor has an efficient broadband cyan emission at 493 nm with full width at half maximum (FWHM) of about 95 nm under 411 nm excitation. Impressively, the luminous intensity of the nitriding phosphor is increased by 30%, the internal quantum efficiency is increased from 41.63% to 61.93%, and the thermal stability is improved from 75%@150 °C to 85%@150 °C, which is better than the commercial green phosphor (77%@150 °C). Finally, a full-visible-spectrum LED with low correlated color temperature (CCT = 5143 K) and high color rendering index (R a = 98.3) is fabricated by employing Ca 2 (Y, Ce)Hf 2 (Al, Si) 3 (O, N) 12 phosphors as cyan emitting component. The results indicate that the nitriding Ca 2 (Y, Ce)Hf 2 (Al, Si) 3 (O, N) 12 phosphors have potential to act as cyan emission phosphors for full-visible-spectrum LEDs. • An azotizing garnet phosphor with improved QE and thermal stability was synthesized. • Structure and luminescent property evolution before/after azotizing were discussed. • Site preference and the 5d→2F 5/2 and 2F 7/2 transitions of Ce3+ were accurately assigned. • The mechanism of the improved thermal stability after azotizing was discussed. • Full-visible-spectrum LEDs can be achieved with high R a and low CCT. [ABSTRACT FROM AUTHOR]

The yellow–orange phosphors Sr 1.99 − x − y Ca x M y Si 1 − y Z y O 4 : 0.01Eu 2+ (M = Y 3+ , K + , Z = Al 3+ , P 5+ , 0 ⩽ x ⩽ 0.9, 0 ⩽ y ⩽ 0.01) were synthesized by the solid state reaction. X-ray diffraction and photoluminescence spectra were utilized to characterize the samples. The results indicate that the phosphors can be efficiently excited by the UV–blue light and show a broad band emission from about 425 to 700 nm. Ca 2+ plays an important role in the red-shift of the emission band in Sr 1.99 − x Ca x SiO 4 : 0.01Eu 2+ . When the Ca 2+ concentration x = 0.7, the emission peak under the excitation of 450 nm reaches a maximum at about 600 nm, which implies that the samples Sr 1.99 − x Ca x SiO 4 : 0.01Eu 2+ could serve as a red phosphor for the blue LEDs. The trace doping of Al 3+ and P 5+ with Y 3+ and K + as charge compensation significantly enhances the emission intensities of Sr 1.29 Ca 0.7 SiO 4 : 0.01Eu 2+ . In addition, thermal properties of typical samples are also carefully investigated. [ABSTRACT FROM AUTHOR]

Abstract: A new Ca2La8(GeO4)6O2 (CLGO) compound has been synthesized via solid-state reaction process for the first time. The crystal structure of CLGO was refined and determined by Maud Program. The photoluminescence spectra (PL), cathodoluminescence spectra (CL), and lifetimes as well as temperature dependence of photoluminescence of CLGO:RE3+ (RE3+=Eu3+, Tb3+, Dy3+, Sm3+, Tm3+) were investigated in detail. Under the excitation of ultraviolet, CLGO:RE3+ (RE3+=Eu3+, Tb3+, Dy3+, Sm3+, Tm3+) show red, green, yellow, orange, violet emission, respectively. [Copyright &y& Elsevier]

• The energy transfer between Bi3+ and Te4+ is realized in Cs 2 ZrCl 6 perovskite. • Bi3+/Te4+ co-doped perovskite can realize color hue evolution from blue to yellow. • High quality WLEDs can be fabricated by Cs 2 ZrCl 6 : Bi3+, Te4+ and UV LED chip. • The phosphor can be exploited in visual light sensor and information transmission. Stable and high-efficiency inorganic lead-free double perovskites have aroused great attention for their application in photoluminescence field. However, most of the double perovskite materials with single dopant cannot realize multi-mode excitation, tunable or full-spectrum emission, which lead to the rare applications in contactless light sensor, encrypted information transmission and white light emitting diodes. Herein, inspired by a traditional methodology of co-doping rare-earth, ns2 type ions (Bi3+ and Te4+) co-doped lead-free perovskite Cs 2 ZrCl 6 is proposed and developed. Comparing to the single dopant, Bi3+/Te4+ co-doped perovskites can exhibit high sensitivity to the excitation wavelength and then emit greatly adjustable emission spectra from ∼457 to 577 nm, which corresponds to the color hue evolution from blue to yellow. Meanwhile, the high resonance energy transfer efficiency process from triplet STEs state of Bi3+ to Te4+ is also proved by employing the excitation/emission spectra and the transient fluorescence spectrum. Based on the efficient energy transfer process, high quality white light (CIE = (0.330, 0.347), CCT = 5608 K, Ra = 85.1), covering the entire visible region, can be obtained under ultraviolet light excitation. These features guarantee its potential application in contactless light sensor, encrypted information transmission and single-phase white light emitting diodes. The above results show that the methodology of co-doping ns2 type ions in Cs 2 ZrCl 6 will open up new opportunities to the multifunctional application field. [ABSTRACT FROM AUTHOR]

Abstract: Ca(8−y)Mn y NaGd(1−x)Ce x (PO4)6F2 (CNGF: xCe3+, yMn2+) (0≤ x ≤0.05, 0≤ y ≤0.16) phosphors were synthesized by solid state reaction. The crystal structure was determined to be apatite-type by XRD refinement. The PLE and PL spectra showed that the energy transfer occurs between Gd3+ to Mn2+ and Ce3+ to Mn2+. And the energy transfer efficiency from Gd3+ to Mn2+ and Ce3+ to Mn2+ in CNGF had been analyzed. The research result revealed that the electric dipole–quadrupole interaction predominates in energy transfer mechanism from Ce3+ to Mn2+ in CNGF. The corresponding CIE coordinates revealed that CNGF: 0.02Ce3+, yMn2+ could be a good yellow phosphor. [Copyright &y& Elsevier]

A new chlorogermanate compound Ca8 Mg( GeO4)4 Cl2 ( CMGC) was synthesized via high-temperature solid-state reaction for the first time. The crystal structure of CMGC had been refined and determined from the XRD profiles by Rietveld refinement method, which belong to space group Fd-3 m with the lattice constants a = b = c = 15.1760(25) Å. Photoluminescence properties of CMGC: Eu2+ phosphors were investigated by absorption spectra, excitation, and emission spectra. The occupy situation and energy transfer were investigated by decay lifetimes and emission spectra under different excitation wavelengths. Thermal stability was also measured. The results show that the absorption spectra of CMGC: Eu2+ phosphors cover from 250 to 500 nm. Under 365 and 435 nm excitation, the emission spectra of CMGC: Eu2+ phosphors show blue-green (centered at 425 and 510 nm) and green (centered at 510 nm) emission, respectively, which attributed to Eu2+ ions occupying different crystal sites. Our results indicated that CMGC: Eu2+ phosphors had a potential application use for white light-emitting diodes. [ABSTRACT FROM AUTHOR]

Abstract: Si–N-doped BaAl12O19:Mn2+ phosphors were synthesized by a conventional solid-state reaction. It reveals that an efficiently host absorption in the vacuum ultraviolet region, which could be ascribed to the restricted Reidinger defects and oxygen vacancies by the Si–N doping. A fortified energy transfer from host to the activators was observed because of the newly formed defect energy levels which generated from the un-equivalence substitution of Si–N for Al–O. The shorter decay time of 4.05ms was obtained which due to the increased defect concentration. This result indicates that Si–N doping BaAl12O19:Mn2+ phosphors would meet the requirements of 3D PDPs. [Copyright &y& Elsevier]

• Novel red light Sr 19 Mg 2 (PO 4) 14 : Eu3+, Sm3+, Pr3+ phosphors were first synthesized. • The structure and spectroscopic features were detailly investigated and discussed. • All the phosphors can exhibit extraordinary color purity and high quantum efficiency. • The thermal stability can still stay strong at 150 ℃. The discovery of high color purity red-emitting phosphors is a major challenge for solid-state lighting materials. Benefitting from highly condensed and flexible framework structure of β -Ca 3 (PO 4) 2 -type compounds, we have successfully prepared three different kinds of novel high color purity red-emitting phosphors Sr 19 Mg 2 (PO 4) 14 : Re3+ (Re3+= Eu3+, Sm3+, Pr3+) by using traditional sintering method. Rietveld refinement, SEM measurement, absorption spectra, emission/excitation spectra, fluorescence decay analysis and emission spectra in terms of different temperature were investigated and discussed clearly. The matrix optical band gap was calculated to be 4.5 eV by reflection data, which indicated the suitable host for rare earth doping. The single doped Eu3+, Sm3+ and Pr3+ phosphors could respectively exhibit characteristic and strong red emission peaks at 614 nm, 598 nm and 642 nm when excited by (near) ultraviolet radiation. Excitingly, all samples could obtain high color purity with the value of 91.6%, 90.6% and 84.8% for Eu3+, Sm3+, Pr3+ ions, respectively. Moreover, the thermal stability can stay strong which still keep over 75% at 150℃ when comparing with that at atmospheric temperature. The quantum efficiency (QE) is another important parameter for phosphors which were measured to be 46.6% for Eu3+, 53.1% for Sm3+ and 10.3% for Pr3+. The present work indicates that the Sr 19 Mg 2 (PO 4) 14 : Re3+ phosphors are efficient red components with extraordinary color purity and high quantum efficiency for industrial applications as solid-state lighting materials. [ABSTRACT FROM AUTHOR]

• Novel CNMP: Dy3+, Tm3+ phosphors with adjustable emission was synthesized. • Detailed excitation and emission property of CNMP: Dy3+, Tm3+ was studied. • Room temperature and temperature dependent decay behavior were investigated. • The energy transfer efficiency and the energy transfer mechanism were investigated. • Thermal quenching behavior and related mechanism were investigated in detail. White light emission phosphors are widely researched for application in lighting and display fields. However, the poor thermal stability is a real problem for the known single-phased white phosphors, which limits their further application. In this paper, Ca 19 Na 2 Mg(PO 4) 14 : x Dy3+, y Tm3+ (CNMP, 0 ≤ x ≤ 0.06, y = 0, 0.01) phosphors with adjustable emission and good thermal stability are synthesized. The X-ray diffraction and X-ray energy dispersive spectrometer measurement distinctly confirm the successful synthesis of CNMP: x Dy3+, y Tm3+ (CNMP, 0 ≤ x ≤ 0.06, y = 0, 0.01). The photoluminescence results reveal that CNMP: Dy3+ shows characteristic excitation peaks in the range of 350–450 nm, and mainly exhibits strong yellow emission around 575 nm ascribed to the 4F 9/2 -6H 13/2 transitions of Dy3+. To compensate the deficiency of blue light emission of CNMP: Dy3+, the trivalent Tm3+ ion is co-doped owing to its characteristic blue emission at 450 nm due to its 1D 2 -3F 4 transitions. Therefore, the emission of CNMP: Dy3+, Tm3+ can be tuned from blue light region with CIE coordinates of (0.1649, 0.0387) to white light region with CIE coordinates of (0.3001, 0.3003) and finally move to yellow light region with CIE coordinates of (0.3732, 0.4493) through adjusting the doping ratio of Dy3+/Tm3+. The energy transfer efficiency and the energy transfer mechanism from Tm3+ to Dy3+ are further investigated. Moreover, CNMP: Dy3+, Tm3+ exhibites a high thermal stability and the emission intensity still keeps 84% of the initial intensity of Dy3+ at 230 °C. These outstanding properties show that Ca 19 Na 2 Mg(PO 4) 14 : Dy3+, Tm3+ have great advantages and potentiality for applying in solid state lighting. [ABSTRACT FROM AUTHOR]

Abstract: The S-doped BaAl12O19:Mn2+ phosphors were synthesized by an environmentally benign synthesis reaction. Photoluminescence spectra, powder X-ray diffraction, energy dispersion spectrum and decay curves were used to evaluate the S-doped BaAl12O19:Mn2+ phosphors. It reveals that sulfur doping would lead to a sharp increase of 33.8% in luminance intensity and only a slightly longer decay time. This could be due to the decrease of defects traps and more covalent crystal field surrounding Mn2+ when sulfur ions occupied the unstable conduction O sites. The result shows that this environmentally benign synthesis is expected to be potentially applicable to the plasma display panels'' industrial production of BaAl12O19:Mn2+ phosphors. [Copyright &y& Elsevier]

• Self-assembled AlN:Dy microstructures were prepared by arc discharge method. • The microstructures were assembled by AlN:Dy nanosheets. • The AlN:Dy microstructures exhibited white emission and room temperature ferromagnetism. Novel self-assembled Dy doped AlN (AlN:Dy) microstructures derived from nanosheets (NSs) were prepared using an improved arc discharge method. The structure, morphology, optical and magnetic properties of AlN:Dy microstructures were characterized by XRD, XPS, FESEM, HRTEM, PL and VSM studies. The electrostatic interactions of NSs arising from Dy3+ doping into AlN and electric field attraction created by arc discharge, are responsible for the formation of self-assembled AlN:Dy microstructures. The AlN:Dy microstructures exhibited an intensive white emission and room temperature ferromagnetism. This work not only demonstrates an effective strategy to assemble complex architectures, but also provides a new opportunity to design multifunctional materials, through doped wide band semiconductor. [ABSTRACT FROM AUTHOR]

In this paper, we reported a novel far-red emitting phosphor Sr 9 Y 2 (WO 6) 4 : Mn4+ and alkaline earth metal Mg2+ ion co-doped phosphor Sr 9 Y 2 (WO 6) 4 : Mn4+, Mg2+. Systematical studies on its crystal structure and luminescence properties are carried out. X-ray powder diffraction confirmed that the pure phase Sr 9 Y 2 (WO 6) 4 : Mn4+ and Sr 9 Y 2 (WO 6) 4 : Mn4+, Mg2+ phosphors show a single phase. Upon 350 nm excitation, the phosphors could emit far-red emission in the range of 600–800 nm, peaking at 680 nm (14,706 cm−1) due to the 2E g →4A 2g transition, with broad spectra overlap with the absorption band of phytochrome P FR. The optimal doping concentration, concentration quenching mechanism, as well as the content and temperature dependent decay times of Sr 9 Y 2 (WO 6) 4 : Mn4+ phosphors are studied in detail. Impressively, Mg2+ dopant is found to strongly improve the luminescence of Mn4+ and the related mechanisms are deeply studied. Ultimately, a far-red light emitting diode lamp is fabricated by exciting a far red phosphor Sr 9 Y 2 (WO 6) 4 : 0.0025Mn4+, 0.01Mg2+ using a 365 nm n-UV illuminating LED chip. Our studies have shown that Sr 9 Y 2 (WO 6) 4 : Mn4+, Mg2+ phosphors have potential application in controlling or adjusting plant growth in plant-lighting. Image 1 • The charge compensation of Mg2+ was performed in the phosphor SYW: Mn4+. • We analyzed the crystal structure of SYW host at the first time. • The luminescence properties of SYW: Mn4+ and SYW: Mn4+, Mg2+ were systematically investigated. • The crystal field strength of SYW: Mn4+, Mg2+ with/without Mg2+ charge compensation were studied. • The SYW: Mn4+, Mg2+ phosphor was incorporated into a far-red LED lamp and its practicality was discussed. [ABSTRACT FROM AUTHOR]

High-aspect-ratio Eu doped AlN (AlN:Eu) nanowires (NWs) were synthesized via direct nitridation strategy. The NWs exhibits a strong green emission of the 5d-4f transition under ultraviolet light excitation. Photoluminescence (PL) spectra and synchrotron angle-dispersive X-ray diffraction (ADXRD) for AlN:Eu NWs were performed under hydrostatic pressures up to above 30 GPa. The pressure-induced monotonic red-shift of emission band (dλ/dP ≈ 5.9 nm GPa−1), as well as changes in the emission band widths, have been correlated with pressure for visible-light optical pressure sensors. As the pressure reaches around 20 GPa, the phase transition of AlN:Eu NWs from the wurtzite to rocksalt was found by the appearance of a PL band and ADXRD peak. The enhancement of transition pressure and bulk modulus in AlN:Eu NWs as compared with other ions doped AlN is considered to be caused by co-dopants of Eu2+ and Eu3+ ions. This work provides an effective strategy for doping large-size rare-earth ions into wide band-gap nitride semiconductor, and demonstrates a straightforward pathway for tuning optical properties through pressure without modifying composition. • Eu doped AlN nanowires were synthesized via an arc discharge method. • Eu doped AlN nanowires exhibited an intensive green emission band at 528 nm. • Photoluminescence properties and structural stability under high pressure were studied. [ABSTRACT FROM AUTHOR]