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Full spectrum white LED plant growth light sources are suitable for use in conditions requiring a high color rendering index. In addition to red and blue light, green light was shown to have a positive impact on plant growth in earlier studies. In this work, a series of Sm3+ doped ZnWO 4 phosphors was prepared using the high-temperature solid-state reaction method. Li+ serves as a charge compensator to reduce lattice defects caused by non-equivalent isomorphism. XRD measurements and Rietveld refinement were used to investigate the phase composition and structural properties of the samples. The luminescent properties of the samples were tested using a fluorescence spectrophotometer. The Li + introduction can significantly improve the energy transfer from the matrix to Sm3+ and the luminescence intensity of Sm 3+ . In addition, this phenomenon was explained with non-equivalent isomorphism and the charge density difference diagram. The LED lamp was prepared using ZnWO 4 : 0.004Sm3+, 0.004Li + phosphor and LED chip. The emitted full spectrum light can match well with the absorption spectrum of plant pigments. The color rendering index of the LED lamp is greater than 91. And the comparative experiment of plant cultivation shows that the prepared LED plant lamp has good effects. The dependence of luminescence properties of ZnWO 4 : 0.004Sm3+, 0.004Li+ phosphor on temperature was determined. Based on fluorescence intensity ratio (FIR) technology, the maximum S aMAX and S rMAX are 52 % K−1 at 453 K and 9.31 % K−1 at 303 K, respectively. As the temperature increases, the chromaticity shift (Δ s) value is 0.254. The benefits of the ZnWO 4 : 0.004Sm3+, 0.004Li+ phosphor are the straightforward synthesis process, low cost, pure phase, full spectrum, high color rendering index, tunable red-to-blue ratio, and temperature monitoring function. Therefore, this phosphor is an ideal material in plant growth and optical temperature measurement. [ABSTRACT FROM AUTHOR]

Novel Pr 3+ , Ho 3+ , and Er 3+ single-doped Ca X Sr Y Ba 1−X−Y WO 4 phosphors were successfully prepared via a facile hydrothermal method. The hydrothermal process was conducted in aqueous condition without the use of any organic solvent, surfactant, or catalyst. The effects of doping-host composition and RE 3+ doping concentration on the emission intensity were investigated to optimize the luminescent properties of Ca X Sr Y Ba 1−X−Y WO 4 :RE 3+ phosphors. Experimental results demonstrate that the morphologies of the products vary gradually and regularly with the change of the host composition, in which the anisotropic growth played a key role. Moreover, the down-conversion emissions of Pr 3+ , Ho 3+ , and Er 3+ in Ca X Sr Y Ba 1−X−Y WO 4 host were successfully realized. After optimizing the luminescent properties, Ca 0.4 Sr 0.6 WO 4 :0.01Pr 3+ , Ca 0.8 Sr 0.2 WO 4 :0.01Ho 3+ , and Ca 0.6 Sr 0.4 WO 4 :0.005Er 3+ exhibited optimal luminescent property, with orange, yellowish-green, and green emissions, respectively. [ABSTRACT FROM AUTHOR]

Dy 3+ and Eu 3+ codoped KSr 4 (BO 3 ) 3 phosphors were successfully synthesized by solid-state reaction process. Under near-ultraviolet (near-UV) excitation, individual Dy 3+ or Eu 3+ ion activated sample exhibits characteristic emissions in their respective regions. In KSr 4 (BO 3 ) 3 :Dy 3+ , x Eu 3+ phosphors, the energy transfer from Dy 3+ to Eu 3+ was revealed to be resonant type by dipole–dipole mechanism. And the critical distance R Dy–Eu was calculated to be 13.95 Å. The energy transfer efficiency of KSr 4 (BO 3 ) 3 :Dy 3+ , x Eu 3+ reached about 20% when the concentration of Eu 3+ was 0.035. Moreover, the emitting colors of Dy 3+ and Eu 3+ codoped samples can be adjusted from the edge of white area to warm white via tuning the activator (Eu 3+ ) doped concentration. More significantly, the chromaticity coordinates (0.334, 0.351) of KSr 4 (BO 3 ) 3 :0.005Dy 3+ , 0.015Eu 3+ sample are extremely adjacent to standard white light (0.33, 0.33). The quantum efficiency of the KSr 4 (BO 3 ) 3 :0.005Dy 3+ , 0.015Eu 3+ phosphor with 389 nm excitation is found to be 42%, demonstrating that the obtained single-component white-emitting phosphor exhibits potential applications for solid state lighting. [ABSTRACT FROM AUTHOR]

Dy 3+ doped and Eu 3+ /Tb 3+ co-doped MMoO 4 (M=Ca, Sr, Ba) phosphors have been successfully prepared via a simple surfactant-free hydrothermal method. Their crystal structure, morphology, and luminescent characteristics were investigated. The results show that the as-prepared CaMoO 4 particles have the cylinder-like shape, SrMoO 4 samples present dumbbell-like shape, and the as-prepared BaMoO 4 products show micro-rods shape with a length of 5–15 μm. MMoO 4 :Dy 3+ phosphors exhibited the characteristic excitation and emission transitions of Dy 3+ and most of the chromaticity coordinates are located in the white-light region. In addition, with increasing Dy 3+ ions concentration the color changes gradually from near blue to near yellow. All the characteristic emissions of Eu 3+ and Tb 3+ can be observed in Eu 3+ /Tb 3+ co-doped MMoO 4 phosphors, and the emission color can be easily tuned from red, through yellow or green-yellow, to green by simply adjusting the relative doping concentrations of the Eu 3+ and Tb 3+ ions. The present work suggests that these phosphors may have potential application for light-emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

Abstract: A series of Eu3+-activated double molybdate phosphors MRE(MoO4)2 (M = Li, Na, K; RE = Gd, Y, Lu) have been successfully prepared via the conventional solid-state reaction method. The effects of alkali cations and rare earth ions on the luminescence of MRE(MoO4)2:Eu3+ were investigated in detail. The experimental results show that the emission intensity was found to decrease with increasing the size of alkali cations or decreasing the size of rare earth ions. Under 393 nm light excitation, all compounds exhibited strong red emission at about 613 nm due to 5D0 → 7F2 transition of Eu3+. Compared with the commercially available red phosphor Y2O3:Eu3+, the emission intensity of the obtained phosphors is much stronger than that of Y2O3:Eu3+. Additionally, the excitation spectra of these phosphors implied that the MRE(MoO4)2:Eu3+ phosphors can absorb not only the emission of near UV-LED chips but also that of blue LED chips. The CIE chromaticity coordinates are close to the National Television Standard Committee (NTSC) standard CIE chromaticity coordinate values for red (0.67, 0.33). All the results indicate that these phosphors are promising red-emitting phosphors pumped by near-UV or blue light. [Copyright &y& Elsevier]

Abstract: Eu3+-activated double tungstates phosphors MLa(WO4)2 (M=Li, Na, K) and NaRE(WO4)2 (RE=Gd, Y, Lu) have been successfully prepared via the conventional solid-state reaction method. The effects of alkali ions and rare earth ions on the luminescence of MLa(WO4)2:Eu3+ and NaRE(WO4)2:Eu3+ were investigated. In MLa(WO4)2:Eu3+ system the emission intensity was found to decrease with increasing the size of alkali ions, and in NaRE(WO4)2:Eu3+ system the emission intensity can be ordered as follows: Lu>Y>Gd. Moreover, under 393nm light excitation all compounds exhibited strong luminescence of 5D0→7F2 at 615nm. The excitation spectra implied that these phosphors can absorb not only the emission of near UV-LED chips but also that of blue LED chips. All the results indicate that these phosphors are promising red-emitting phosphors pumped by near-UV or blue light. [Copyright &y& Elsevier]

Abstract: Eu3+ and Tb3+ co-doped NaLa(MoO4)2 phosphors with various shapes have been synthesized by a simple conventional hydrothermal method. The morphology of the materials was found to be manipulated by changing the pH value of the precursor hydrothermal media. Uniform NaLa(MoO4)2 3D microspheres could be trapped at pH 5 and the spindle-like NaLa(MoO4)2 microstructures were obtained at pH 7. When the pH value was adjusted to 9, the flower-like NaLa(MoO4)2 microstructures were obtained. The luminescent properties of the NaLa(MoO4)2:Eu3+/Tb3+ samples with different morphologies prepared at different starting pH values were studied. The results show that the emission intensity of the product obtained at pH 5 is the strongest. Besides, under ultraviolet excitation the luminescence colors of NaLa(MoO4)2 samples co-doped with Eu3+ and Tb3+ can be tuned from red, through yellow and green–yellow, to green by simply adjusting the relative doping concentrations of the activator ions. This merit of multicolor emissions in the visible region endows the as-prepared products with potential application in the fields of light-display systems and optoelectronic devices. [Copyright &y& Elsevier]

Abstract: Pompon-like NaLa(MoO4)2:Dy3+ phosphors have been successfully prepared via a hydrothermal method using ammonia as pH value regulator. The hydrothermal process was carried out under aqueous condition without the use of any organic solvent, surfactant, and catalyst. The experimental results demonstrate that the obtained NaLa(MoO4)2:Dy3+ phosphor powders are single-phase scheelite structure with tetragonal symmetry. Moreover, the phosphor under the excitation of 390 and 456nm exhibited blue emission (486nm) and yellow emission (574nm), corresponding to the 4F9/2→6H15/2 transition and 4F9/2→6H13/2 transition of Dy3+ ions, respectively. In addition, the yellow-to-blue emission intensity ratio (Y/B) can be changed with the doped concentration of Dy3+ ions. All chromaticity coordinates of the obtained NaLa(MoO4)2:Dy3+ phosphors are located in the white-light region. The results indicate that this kind of phosphor may has potential applications in the fields of near UV-excited and blue-excited white LEDs. [Copyright &y& Elsevier]

Abstract: LaPO4: Eu3+, Sm3+ nanorods have been successfully prepared by a designed two-step hydrothermal method. The whole process was carried out under aqueous conditions without the use of any organic solvent, surfactant, or catalyst. The crystal structure, morphology have been characterized by XRD, FT-IR, SEM and TEM, respectively. The detailed conversion process of the product LaPO4 nanorods has been investigated on the basis of time-dependent XRD experiments and SEM experiments. Moreover, the LaPO4 samples doped with Eu3+ and Sm3+ under ultraviolet excitation showed red emission corresponding to the 5D0–7F1 transition of the Eu3+ ions. The doped Sm3+ was found to be efficient to sensitize the emission of Eu3+ and be effective to extend the absorption of near-UV light with wavelength of 400–405nm. The effect of the concentration of Sm3+ on the emission intensities of the phosphor LaPO4: Eu3+, Sm3+ is also investigated. These samples could be potentially used in the fields of near UV-excited white-light-emitting diode and optoelectronic devices. [Copyright &y& Elsevier]

Two series of ZnWO 4 : RE3+, Li+ (RE = Sm, Eu) phosphors were prepared using the facile solid-state reaction sintering at 800 °C. Its structural properties were investigated by XRD and Rietveld refinement method. The luminescence properties of the phosphors were studied, and they can be used in the white light-emitting diodes (wLEDs). Li+ was introduced into phosphors as a charge compensation agent. The influence of Li+ on the phase and luminescent properties was studied. The Vienna Ab-initio Simulation Package (VASP) software was employed to calculate the charge density differences. It is shown that the ZnWO 4 : Sm3+, Li+ phosphor has potential application in the plant growth LEDs. Image 1 • Two series of ZnWO 4 : Sm3+ or Eu3+ phosphors were prepared by solid state method. • The broad excitation peak around 305 nm perfectly matches the AlGaN semiconductor. • Emission color can be turned from white to red by adjusting concentration of RE3+. • Two white phosphors (ZnWO 4 : 0.004Sm3+, Li+; ZnWO 4 : 0.002Eu3+, Li+) were obtained. • Sm3+ doped ZnWO 4 phosphor has potential application in plant growth LEDs. [ABSTRACT FROM AUTHOR]

NaLa0.96 (MoO4)2:0.02Eu3+,0.02Tb3+ phosphors are hydrothermally prepared from aqueous solutions of La(NO3)3, Eu(NO3)3, Tb(NO3)3, and Na2MoO4. [ABSTRACT FROM AUTHOR]

A series of undoped and Eu3+ doped YOF and Y1−xGdxOF (x = 0–0.7) crystals were prepared via a urea based homogeneous precipitation method followed by a heat treatment process. After Gd3+ doping, we observed the crystal phase transition, morphology transformation, and greatly enhanced luminescence properties of the YOF crystals. The results reveal that the addition of Gd3+ can promote the phase transition from the hexagonal phase to the rhombohedral phase and the morphology transformation from spheres, though a mixture of rods and spheres, to spheres. The luminescence properties of Eu3+ doped YOF phosphors were investigated upon UV excitation and the quenching concentration of Eu3+ was found to be 10 mol%. More importantly, the luminescence intensity after doping a certain amount of Gd3+ increased by 31 times compared to that of the Gd3+ free sample, which may be due to the modification of the crystal field and the crystal phase of YOF, providing an effective way to gain numerous Gd3+ doped luminescent materials. These results show that the Gd3+ doped red phosphors have potential applications in white light emitting diodes. [ABSTRACT FROM AUTHOR]

A novel, fast and simple method was developed to synthesize the undoped and lanthanide-doped yttrium oxide hollow nanospheres (Y 2 O 3 ⋅HNSs) with multicolored downconversion emission under mild conditions by employing poly (acrylic acid sodium salt) microspheres (PAAS MSs) as active templates followed by a subsequent calcination process. The structure, morphology, formation process, and fluorescent properties are well investigated using various techniques. The results show that the samples can be well indexed to the pure cubic phase of Y 2 O 3 . The possible formation mechanism of the PAAS MSs, PAA-Y precursor, and Y 2 O 3 HNSs are proposed and discussed in detail. Upon ultraviolet excitation, the obtained Y 2 O 3 :Ln 3+ (Ln = Eu, Dy, Er, Tm) HNSs exhibit strong red, yellow–green, blue, yellow emission, respectively. Moreover, a novel single-phased and near-UV-pumped white-light-emitting phosphor Y 2 O 3 :Tm 3+ , Dy 3+ was also successfully fabricated through optimizing the molar ratio among Tm 3+ and Dy 3+ in the Y 2 O 3 host. This material may find potential applications in field-emission display devices and white ultraviolet light-emitting diodes (UV LEDs). Furthermore, this synthesis route may be of great significance in the preparation of other hollow spherical materials. [ABSTRACT FROM AUTHOR]

A series of YBO 3 :Ln 3+ (Ln = Eu, Tb) phosphors have been successfully synthesized for the first time via a simple solution-based hydrothermal method using Y(OH)CO 3 :Ln 3+ (Ln = Eu, Tb) colloid spheres and Na 2 B 4 O 7 ·10H 2 O as the precursors. The as-prepared phosphors present uniform ellipsoid-like morphology and have a diameter of about 2.5 μm. FTIR confirms the formation of vaterite-type YBO 3 can be synthesized by this method. The molar ratio of Y/B plays an important role in controlling the product morphology. The possible formation mechanism for the ellipsoid-like microcrystals was proposed on the basis of a series of time-dependent experiments. Even in such a simple solution-based hydrothermal reaction system, the formation of YBO 3 microcrystals went through complex crystallization and crystal growth processes: a small amount of random shaped particles served as precursors for the crystals initially formed which continuously grew into large flower-like YBO 3 , the excess borax resulted in the dissolution of flower-like YBO 3 and the formation of new YBO 3 particles. Moreover, there exists characteristic luminescence of Eu 3+ and Tb 3+ individually when doping them in the YBO 3 host. The quenching concentration of YBO 3 :Eu 3+ and YBO 3 :Tb 3+ is 25% and 20%, respectively. [ABSTRACT FROM AUTHOR]

Abstract: The NaLa(MoO4)2:Ce3+,Tb3+ phosphors were synthesized by a high temperature solid-state reaction. Co-doping of Ce3+ enhances the emission intensity of Tb3+ greatly by transferring its excitation energy to Tb3+. Through an efficient energy transfer process, the obtained phosphors exhibit both a indigo emission of Ce3+ and a yellowish green emission of Tb3+ with considerable intensity under near-ultraviolet excitation (339nm). The energy transfer mechanism from Ce3+ to Tb3+ in NaLa(MoO4)2 host was demonstrated to be dipole–quadrupole interaction. The varied emitted color of the phosphors from indigo to yellow-greenish can be achieved by properly tuning the relative ratio of Ce3+ and Tb3+ through the energy transfer from the Ce3+ to Tb3+ ions. These results indicate that the NaLa(MoO4)2:Ce3+,Tb3+ phosphors have potential applications as an UV-convertible phosphor for white light emitting diodes because of its effective excitation in the near ultraviolet range. [Copyright &y& Elsevier]

Abstract: The Sr2Al2SiO7:Eu2+, Ce3+ phosphors were synthesized by a high temperature solid-state reaction. Effective energy transfer occurs in Ce3+ and Eu2+ co-doped Sr2Al2SiO7 due to large spectral overlap between the emission of Ce3+ and excitation of Eu2+ ions. Co-doping of Ce3+ enhances the emission intensity of Eu2+ greatly by transferring its excitation energy to Eu2+ ions. The critical distance has been estimated to be about 1.83nm by spectral overlap method. Furthermore, the developed phosphors can generate lights from blue to green region under the excitation of UV radiation by appropriately tuning the activator content. The Sr2Al2SiO7:Eu2+,Ce3+ phosphors are promising phosphors for warm-white-light-emitting diode because of its effective excitation in the near ultraviolet range. [Copyright &y& Elsevier]

Graphical abstract A series of ZnWO 4 : Eu3+, M+ (Li, Na, K) phosphors were prepared using a facile solid-state reaction method. After the different alkali metals introduction, emission spectra have changed obviously. The color of the emitting light can be tuned from greenish blue to white and finally to the red via co-doping different alkali metals. Highlights • A series of ZnWO 4 : Eu3+, M+ phosphors were prepared by solid-state reaction. • The broad excitation peak from 280 to 315 nm matches perfectly AlGaN based LED. • The emission spectra change obviously when the alkalis co-doped into the host. • Emitting light colors can be tuned from greenish blue to white finally to the red. Abstract A series of ZnWO 4 :Eu3+, M+ (Li, Na, K) phosphors were prepared using a facile solid-state reaction method by sintering at 800 °C. The XRD patterns of the phosphors indicate that the Eu3+ and M+ ions have successfully been introduced into the ZnWO 4 lattice. Their luminescent properties have been studied. The broad excitation peak from 280 to 315 nm by monitoring emission at 616 nm perfectly matches the wavelength range of deep UV LED based on AlGaN semiconductor. When the doping concentration of Eu3+ exceeds 2% in the ZnWO 4 : Eu3+, the luminescence intensity of Eu3+ gradually decreases due to the formation of impurity Eu 2 (WO) 4. The alkali metals are added into the ZnWO 4 as a charge compensator. After the introduction of alkali metals, emission spectra have changed obviously. The addition of Li+ can effectively promote the energy transfer from WO 4 2− to Eu3+. The Commission Internationale de L'Eclairage (CIE) chromaticity color coordinates are calculated. The color of the emitting light can be tuned from greenish blue to white and finally to the red via co-doping different alkali metals. [ABSTRACT FROM AUTHOR]

Abstract The Dy3+ or/and Sm3+ doped LiLa(WO 4) 2 phosphors are synthesized by a facile solid state reaction method. The phase and luminescence properties of the phosphors are investigated. The powder X-ray diffraction (XRD) results show that the phosphor has a tetragonal phase crystal structure. The quenching concentration of single doped Dy3+ and Sm3+ in the LiLa(WO 4) 2 are determined to be 6% and 3%, respectively. Under the excitation of 404 nm, warm white light is obtained in the co-doped phosphors. With the concentration of Sm3+ increasing, the correlated color temperature (CCT) gradually decreases from 3090 to 2453 K. Two kinds of energy transfer may exist at the same time. The overlap between the emission spectrum of Dy3+ and the excitation spectrum of Sm3+ reveals that the energy of Dy3+ can transfer to Sm3+ via radiation. Another way of energy transfer, that is non-radiative energy transfer, is attributed to the excited state of Dy3+ (4F 9/2) slightly higher than that of Sm3+ (4I 19/2). The calculation results show that non-radiative energy transfer process from Dy3+ to Sm3+ ions is predominated by quadrupole–quadrupole interaction. Graphical abstract Image Highlights • Dy3+ or/and Sm3+ doped phosphor powders are synthesized using a facile solid-state reaction. • The quenching concentration of single doped Dy3+ and Sm3+ in the LiLa(WO 4) 2 are determined to be 6% and 3%, respectively. • The warm white light is obtained in the co-doped phosphors LiLa(WO 4) 2: 0.06Dy3+, ySm3+. • The mechanism of energy transfer from Dy3+ to Sm3+ are discussed. [ABSTRACT FROM AUTHOR]

A series of LiGd(MO 4 ) 2 : Sm 3+ , Tb 3+ (M = Mo, W) phosphors was prepared by a conventional solid state reaction method. Powder X-Ray diffraction (XRD) analysis reveals that the compounds are of the same structure type. Their luminescent properties have been studied. The optimal doping concentrations are 8% for Sm 3+ and 18% for Tb 3+ in the LiGd(MoO 4 ) 2 host. Sm 3+ and Tb 3+ have different sensitivity to the Mo/W ratio. For LiGd(MoO 4 ) 2-X (WO 4 ) X : Sm 3+ (X = 0, 0.4, 0.8, 1.2, 1.6, 2.0), the strongest emission intensity is 1.766 times than that of the weakest, while 171 times for LiGd(MoO 4 ) 2-X (WO 4 ) X : Tb 3+ . The experimental results show that Mo/W ratio strong influences on the properties of LiGd(MoO 4 ) 2-X (WO 4 ) X : Tb 3+ . With the increasing of WO 4 2− groups concentration, the shape of characteristic excitation peaks of Tb 3+ is almost the same and the excitation intensity gradually increase. Moreover, the energy transfer from Tb 3+ to Sm 3+ has been realized in the co-doped phosphors. The experimental analysis and theoretical calculations reveal that the quadrupole–quadrupole interaction is the dominant mechanism for the Tb 3+ →Sm 3+ energy transfer. Therefore, luminous intensity can be adjusted by different sensitivities to matrix composition and energy transfer from Tb 3+ →Sm 3+ . By this tuning color method, white-light-emitting phosphor has been prepared. The excitation wavelength is 378 nm, and this indicates that the white-light-emitting phosphor could be pumped by near-UV light. [ABSTRACT FROM AUTHOR]

Uniform cake-like and olive-like GdBO 3 samples have been successfully synthesized for the first time via a simple solution-based hydrothermal method using Gd(OH)CO 3 colloid spheres and NaBO 2 ·4H 2 O as the precursors. It was found that small amount ethanol in the hydrothermal process was responsible for determining the shape of products. The FT-IR analysis indicates that vaterite-type GdBO 3 can be synthesized by this method. The obtained cake-like and olive-like GdBO 3 with rough surfaces have similar mircostructures which are composed of numerous nanoparticles. Time-dependent experiments were employed to study the possible formation mechanism. The formation of cake-like and olive-like GdBO 3 mircostructures self-assembled of nanoparticles can be ascribed to the Ostwald ripening process. A detailed investigation on the photoluminescence (PL) properties of GdBO 3 :Eu 3+ samples with different morphologies indicates that the PL properties of as-obtained GdBO 3 :Eu 3+ phosphors are dependent on their morphologies. The effect of Eu 3+ doping concentration on PL intensity was also investigated and the quenching concentration of GdBO 3 :Eu 3+ is 20%. [ABSTRACT FROM AUTHOR]

In the presence of polyethylene glycol (PEG), we first investigate a facile hydrothermal process to fabricate CdMoO 4 :Tb 3+ green phosphor. The morphology and size of the products can be controlled by simply tuning the PEG amounts and the reaction time. The XRD results show that the CdMoO 4 :Tb 3+ can be indexed to CdMoO 4 phase. FE-SEM results revealed that the pure CdMoO 4 was a sphere with a diameter of about 2.6 μm. The photoluminescence (PL) properties of CdMoO 4 :Tb 3+ phosphors indicated energy transfer from MoO 4 2 - groups to Tb 3+ . PL spectra indicated the phosphors emitted green light centered at 544 nm under ultraviolet excitation. Simultaneously, this novel and efficient pathway could open new opportunities for further investigating about the properties of molybdate materials. [ABSTRACT FROM AUTHOR]

Monodisperse pancake-like/flower-like/leaf-like GdBO 3 samples have been successfully synthesized via a designed hydrothermal conversion method using H 3 BO 3 , Na 2 B 4 O 7 ·10H 2 O, or NaBO 2 ·4H 2 O as boron sources, respectively. It was found that different boron sources have crucial influences on the formation and morphology of the products. The Gd(OH) 3 nanorods precursors were prepared through a simple hydrothermal process, which then served as sacrificial templates for the fabrication of GdBO 3 micropancakes/microflowers/microleaves via a hydrothermal conversion process. FT-IR spectra confirm that vaterite-type GdBO 3 can be synthesized by this method. The possible formation mechanisms for different microstructures were put forward on the basis of a series of time-dependent control experiments. The products have similar stacked arrangements driven by the minimization of the interfacial and surface energy of the hydrothermal system. An investigation on the photoluminescence (PL) properties of GdBO 3 :Eu 3+ samples with different morphologies indicates that the PL properties of as-obtained GdBO 3 :Eu 3+ phosphors are strongly dependent on their morphology and crystallinity. The flower-like structure exhibits the strongest red emission. [ABSTRACT FROM AUTHOR]

Highlights: [•] Sphere-like SrMoO4 micro-architectures have been synthesized by sonochemistry process. [•] The possible formation process of the SrMoO4 hierarchical structures was discussed. [•] The Ln3+-doped SrMoO4 microspheres exhibit strong light emissions with different colors. [•] The energy transfer process from host to rare earth ions were investigated systematically. [ABSTRACT FROM AUTHOR]

Highlights: [•] OmimPF6 acts not only as a reactant but also as a morphology-directing agent was introduced to prepare uniform LuF3 nanocrystals. [•] Morphology and size-controlled synthesis of rare earth doped LuF3 for the first time, different shapes of the orthorhombic LuF3 nanocrystals were obtained in this research. [•] The effect of different sizes and morphologies on luminescence properties has also been discussed. [•] This study provides more alternatives of rare earth fluorides that exhibit strong characteristic emission, and further complements the exploration of Lu-based nanomaterials, which may have unique properties that the Y/Ln-based nanoparticles do not possess and may serve as versatile luminescent phosphors for further application. [ABSTRACT FROM AUTHOR]

Abstract: Uniform YF3 nanocrystals were prepared through a facile ethylene glycol (EG)/ionic liquid interfacial synthesis route in a imidazolium ionic liquids (1-octyl-3-methylimidazolium hexafluorophosphate) with the ionic liquids acting as both reagents and templates. The partial hydrolysis of PF6 − was utilized to introduce a fluoride source. X-ray diffraction (XRD), field emission scanning microscopy (FE-SEM) and transmission electron microscopy (TEM) have been used to study the morphologies and crystal structure. The detailed growth mechanism of the YF3 nanocrystals was researched. Furthermore, under ultraviolet exaltation, the phosphor of YF3:Eu3+ and YF3:Tb3+ shows red and green emission, corresponding to 5D0–7F1 transition of Eu3+ and 5D4–7F5 transition of Tb3+. The emission spectrum of YF3:Ce3+ phosphor exhibits one dissymmetrical band extending from 350 to 500nm with a maximum at about 383nm. A bright fluorescent yellow emission at 574nm and blue emission at 487nm were observed in the YF3:Dy3+. These novel nanocrystals could be potentially used in biolabels and light emitting diodes (LEDs). [Copyright &y& Elsevier]