Multicomponent Hybrid Precursors Research Articles

Photoluminescence Enhancement Effect of CeO2 in Rare Earth Composites MM′O3/CeO2 and MM′O3/CeO2: Pr3+ (M = Ca, Sr; M′ = Ti, Zr)

In the context, a modified sol-gel technology was afford to the synthesis of rare earth composite ceramic phosphors MM'O(3)/CeO(2) and MM'O(3)/CeO(2): Pr(3+) (M = Ca, Sr; M' = Ti, Zr) with multicomponent hybrid precursors were composed. The micromorphology, particle size and photoluminescence properties were studied with XRD, SEM and luminescent spectroscopy in detail. Both XRD and SEM indicated the particle sizes were in the submicrometer range of 100-300 nm. The photoluminescence for these ceramic phosphors were studied in details with the different component of host (molecular ratio of Sr, Ca and Ti, Zr), presenting a broad spectral band in the visible blue-violet region with the maximum excitation peak at 449 nm and a wide emission range with a maximum peak at 619 nm, which was ascribed to be the characteristic transition of Pr(3+) ((1)D(2) --> (3)H(4)). These phosphors can be expected for visible light conversion (blue --> red) materials. Especially it can be found that the introduction of CeO(2) can enhance the luminescence intensity of MM'O(3) and MM'O(3): Pr(3+).

Co-precipitation synthesis and photo-luminescence of Y1−xAlO:Eux3+ and (GdyY1−y)0.93AlO3:Eu0.073+ powder phosphors

Abstract Y 1− x AlO 3 :Eu x 3+ and (Gd y Y 1− y ) 0.93 AlO 3 :Eu 0.07 3+ powder phosphors have been synthesized by co-precipitation. When the multi-component hybrid precursors are sintered at 1200 °C for 2 h non-agglomerative powder phosphors can be obtained with particle sizes ranging from 300 nm to 600 nm. Phosphor structure and morphology were examined by X-ray diffraction and field emission scanning electron microscopy. Luminescence spectra of these phosphors have been investigated in order to examine the Eu 3+ doping concentration and the host matrix compositional effects on the photoluminescent behaviors. The emission spectra have a strong emission at about 614 nm corresponding to the electric dipole 5 D 0 → 7 F 2 transition of Eu 3+ in all compounds. The optimum molar concentration for obtaining the highest PL intensity were x = 0.07 and y = 0.7, respectively.

Sol–gel synthesis and photoluminescence of RE 3BO 6: Eu 3+/Tb 3+ (RE = Y, Gd) microcrystalline phosphors from hybrid precursors

Novel phosphors of Eu 3+/Tb 3+ doped RE 3BO 6 (RE = Y, Gd) have been prepared using an original modified in situ sol–gel synthesis route. Different optimized organic media were mixed with rare earth coordination polymers, and tri- n-butyl borate was added to assemble inorganic/organic multi-component hybrid precursors. After calcinations of the resulting precursors at 1000 °C, target phosphors were obtained. The microstructure and morphology information of the phosphors were investigated via the technique of X-ray powder diffraction (XRD) and scanning electronic microscopy, and it has been shown that these phosphors present symmetrical distribution and high packing density, whose grain sizes were around 200 nm. Analyzed by luminescent spectra, these phosphor particles show narrow lines of emissions respectively originating from their characteristic transitions, and the dominating emission peak is due to the hypersensitive transition. The RE 3BO 6: Eu 3+/Tb 3+ (RE = Y, Gd) phosphors can be expected to gain more practical applications in commercial phosphors and other luminescent materials used in advanced devices.

Synthesis and luminescence properties of REAl 3(BO 3) 4:Eu 3+/Tb 3+ (RE = Y, Gd) phosphors from sol–gel composition of hybrid precursors

Starting from rare earth nitrates and tri- n-butyl borate, Eu 3+/Tb 3+ doped REAl 3(BO 3) 4 (RE = Y, Gd) phosphors were synthesized by a modified sol–gel process derived from multi-component hybrid precursors. The microstructure and morphology of the phosphors were investigated by X-ray powder diffraction (XRD) and scanning electronic microscope; which indicates that these phosphors show good crystalline state and particle size of 100–200 nm order, specially presenting the novel cubic micro-rod patterns. The excitation spectra show a strong spectral band in narrow ultraviolet region of 200–300 nm, while there are still some apparent weak absorption in long-wavelengths region of 300–500 nm. The corresponding emission spectra indicate that these crystalline phosphors exhibit photoluminescence of the characteristic transitions of RE 3+. The effects of doping concentration on emission intensities were examined, suggesting the quenching concentration of different activated ions in different phosphors. In addition, luminescence intensity presented by the same RE 3+ ion doped concentration among different systems was also compared.

In situ co-precipitation synthesis and photoluminescence of YxGd1−xVO4:Tm3+ microcrystalline phosphors by hybrid precursors

YxGd1−xVO4:Tm3+ (5mol%) phosphors were prepared by in situ co-precipitation technology with the different content ratio of Y/Gd (x=0.2,0.3,0.4,0.5,0.6,0.8, respectively). During the process, rare earth coordination polymers with o-hydroxylbenzoate were used as precursors, composing with polyethylene glycol (PEG) as dispersing media. After heat-treatment of the resulting multicomponent hybrid precursors at 900°C, the samples were obtained. SEM indicated the particles present good crystalline state, whose crystalline grain sizes were about 0.2–2μm. Under the excitation of 257nm, all the materials show the characteristic emission of Tm3+ which is the strong blue emission centered at 475nm originating from 1G4→3H6 of Tm3+. Besides this, concentration quenching appears in the system of YVO4:Tm3+ and GdVO4:Tm3+. And when x reaches 0.5, the system of YxGd1−xVO4:Tm3+ shows the strongest blue emission.

Photoluminescence of Y 0.6Gd 0.4NbO 4:Eu 3+/Tb 3+ micrometric phosphors derived from hybrid precursors

Y 0.6Gd 0.4NbO 4: × Eu 3+/Tb 3+ mol% phosphors with different dopant concentrations have been synthesized by a modified wet-chemical technology named as in-situ chemical co-precipitation from multicomponent hybrid precursors. Their microstructure, micromorphology and particle sizes have been analyzed by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). Those phosphors present interesting morphology, just like “cobblestone” with about 1.0 μm in dimension. Besides this, the dependence of the Red to Orange (RO) emission for Eu 3+ and the Green to Blue (GB) emission for Tb 3+ in Y 0.6Gd 0.4NbO 4 host together with other fluorescent properties on the activator concentration has been discussed. It was shown that the RO value of Eu 3+ varies much with the doping concentration, but the GB value of Tb 3+ almost remains constant.

Novel YNbO 4:RE 3+ (RE = Sm, Dy, Er) microcrystalline phosphors: Chemical co-precipitation synthesis from hybrid precursor and photoluminescent properties

In this paper, a novel modified in situ chemical coprecipitation technology was put forward and firstly achieved the synthesis of a series of novel microcrystalline phosphors: YNbO 4:RE 3+ (RE = Sm, Tb, Er). Among rare earth coordination polymers were adopted as precursors for the rare earth oxides sources, and polyethylene glycol (PEG) was introduced to form the hybrid polymeric systems with rare earth coordination polymers. Together with other functional components such as ammonia to adjust pH value, the multicomponent hybrid precursors were composed by in situ coprecipitation process. After the calcination, YNbO 4:RE 3+ phosphors were characterized with XRD and SEM with the particle sizes were in the range of 0.5–3 μm. The photoluminescence properties of YNbO 4:RE 3+ phosphors were compared to investigate as a function of activated RE 3+ ions’ concentration, which revealed they exhibit apparent characteristic luminescence 4G 5/2 to 6H 5/2,7/2,9/2 for Sm 3+, 4F 9/2 to 6H 15/2,13/2,11/2 for Dy 3+ and 2H 11/2 ( 4S 3/2) → 4I 15/2 for Er 3+ under ultraviolet excitation. The photoluminescent intensities of the three series phosphors were compared with the different doping concentration and no quenching effect was found in the range of concentrations in this research. Besides this, strong emission for charge-transfer-band of NbO 4 3− can be also checked.

Sol–gel composition of hybrid precursors to synthesize RE xGd 1− xAlO 3:Eu 3+ (RE = La, Y) phosphors

RE x Gd 1− x AlO 3 (RE = Y, La) doped with Eu 3+ was synthesized by a modified sol–gel technology with multicomponent hybrid precursors. Both X-rays diffraction (XRD) and especially scanning electronic microscope (SEM) show that these phosphors exhibit the homogenous grain-like microstructure and particle sizes in the range of 30–50 nm. The co-doping La 3+ and Y 3+ cannot change the crystal structure; all of them retain the crystal structure as that in GdAlO 3 agreeing with the JCPDS Card shown. The photoluminescence property of RE x Gd 1− x AlO 3:Eu 3+ (RE = La, Y) was compared to investigate as a function of Eu 3+ ions concentration, which revealed that these phosphors showed the quenching of the 5D 0 emission for high concentration.

Chemical co-precipitation of hybrid precursors to synthesize Eu3+/Dy3+ activated YNbxP1−xO4 and YNbxV1−xO4 microcrystalline phosphors

A modified wet-chemical synthesis technology was put forward to fabricate Eu3+/Dy3+ doped with YNbxP1−xO4 and YNbxV1−xO4 phosphors with varying x from the assembly of multicomponent hybrid precursors. The morphologies have been found to be 1–2μm crystalline spheres using XRD and SEM. The red photoluminescence intensity reaches the strongest in YNb0.8P0.2O4:Eu3+ and YNb0.1V0.9O4:Eu3+ phosphors and the red to orange intensity ratio (RO) values decrease with the content of P(V) increasing. Besides this, the optimum concentration for Dy3+ luminescence in YNb0.5P0.5O4 is 1mol%, while that in YNb0.5V0.5O4 is 0.5mol% or lower than 0.5mol%. The yellow to blue intensity ratio (YB) value of Dy3+ increases when the Dy3+ concentration increases from 0.5 to 8mol% in YNb0.5P0.5O4; however, that of Dy3+ does not vary much in YNb0.5V0.5O4 matrix.

Matrix-inducing synthesis and luminescence of Zn 2SiO 4: xTb 3+ submicrometer phosphors derived from the sol–gel assembling of different multicomponent hybrid precursors

Zn 2SiO 4: xTb 3+ submicrometer phosphors with different content of doping Tb were matrix-inducing synthesized by composing with rare earth salicylate coordination polymers (or rare earth nitrates), polyacrylamide (PAM) (or polyvinyl alcohol, PVA) both as fuel and dispersing media, among x = 0.02, 0.04, 0.06, 0.08 and 0.10, respectively. Their structures have been investigated to be composed of submicrometer-size grains of around 100–200 nm with a Willemite structure (α-Zn 2SiO 4) using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photoluminescence of Zn 2SiO 4:Tb 3+ was investigated as a function of Tb 3+ ions concentration and the results revealed that these submicrometer materials showed a strong green emission from 5D 4 to 7F 5 at 542 nm. For the sample with higher Tb 3+ concentration, a cross relaxation process between Tb 3+ ions results in the quenching of the corresponding 5D 3 blue emission.

Matrix-induced synthesis and photoluminescence of RE 2SiO 5: Eu 3+ (RE = Gd, Y) submicrometer phosphors derived from sol–gel assembly of hybrid precursors

In the context, rare earth (Gd, Y and Eu) coordination polymers with salicylic acid and their nitrates were used as precursors for the luminescent species, which composed with the polyacrylamide (PAM) to form interpenetrating polymeric network systems as dispersing media. Through the sol–gel process of silicate sources (tetraethyl orthosilicate, TEOS), the multicomponent hybrid precursors were assembled and then series of submicrometer phosphors of RE 2SiO 5: Eu 3+ (RE = Gd, Y) were synthesized after the thermal decomposition. Both X-ray diffraction (XRD) and scanning electronic microscope (SEM) show that these materials possesses the submicrometer size of 80–200 nm. The photoluminescent properties show these submicrometer phosphors exhibit characteristic red emission at 612 nm.

LuVO4:RE3+ (RE=Sm, Eu, Dy, Er) phosphors by in-situ chemical precipitation construction of hybrid precursors

In the context, a novel synthesis technology was applied to LuVO4:RE3+ (RE = Sm, Eu, Dy, Er) phosphors for the firstly time. Rare earth coordination polymers with aromatic carboxylic acids were used as the precursors of rare earth oxide components, subsequently polyethylene glycol (PEG) and ammonium vanadate (NH4VO3) were composed to assemble inorganic/organic hybrid polymeric dispersing media by an in-situ chemical coprecipitation process. After heat treatment of the resulting multicomponent hybrid precursors at 1100 °C, LuVO4:RE3+ phosphors were firstly synthesized. Both XRD and SEM indicated the particles presented good crystalline state, whose crystalline grain sizes were in the range of around 0.5–2 μm. The excitation spectra show a broad spectral band in narrow ultraviolet region of 200–350 nm, while no apparent or very weak absorption appears in long-wavelengths region of 350–500 nm. The corresponding emission spectra indicate that these crystalline phosphors exhibit photoluminescence of the characteristic transitions of RE3+. This technology can be expected to apply to prepare high efficient micron rare earth oxylates for practical development in luminescent materials and devices.

In situ Sol—Gel Composition of Inorganic/Organic Polymeric Hybrid Precursors to Synthesize Red‐Luminescent CaTiO3:Pr3+ and CaTi0.5Zr0.5O3:Pr3+ Phosphors.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Sol-gel synthesis of YxGd2−xSiO5:Eu3+ phosphors derived from the in situ assembly of multicomponent hybrid precursors

Abstract Using rare earth coordination polymers with salicylic acid as precursors for the luminescence species YxGd2−xSiO5:Eu3+, composing the polyvinyl alcohol (PVA) as dispersing media, nanophosphors of YxGd2−xSiO5:Eu3+ (x = 0.10, 0.25, 0.50, 0.75, 0.90) with different molar ratio of Y and Gd were synthesized by the sol-gel process. Both X-ray diffraction and scanning electronic microscope show that these materials have the nanometer size of 100–200 nm. These nanometer materials exhibit red emission at 612 nm. When x = 0.5, Y0.5Gd1.5SiO5:Eu3+ shows the strongest emission intensity comparing with other molar ratio of Y to Gd.

Matrix induced synthesis of LaNbO4:Tb3+ phosphors by in situ composing hybrid precursors

Abstract In this paper, a novel modified in situ chemical coprecipitation technology was achieved to synthesize LaNbO4 doped with Tb3+ phosphors. Among rare earth (La and Tb) coordination polymers were adopted as precursors for the La and Tb oxides sources, and polyethylene glycol (PEG) was introduced to form the hybrid polymeric systems with rare earth coordination polymers. Accompanied with other functional components, the multicomponent hybrid precursors were composed by an in situ coprecipitation process. After the calcination, LaNbO4:Tb3+ phosphors were obtained, whose particle sizes were in the range of 1–3 μm characterized by XRD and SEM. The photoluminescence properties of LaNbO4:Tb3+ phosphors were compared to investigate as a function of Tb3+ ion concentrations, which revealed that these nanophosphors showed a strong visible green emission from 5D4 to 7F5 at 543 nm under ultraviolet excitation. The luminescence of Tb3+ quenches emission for a charge-transfer-band of NbO 4 3 - .

In situ sol–gel composition of inorganic/organic polymeric hybrid precursors to synthesize red-luminescent CaTiO 3:Pr 3+ and CaTi 0.5Zr 0.5O 3:Pr 3+ phosphors

In this paper, rare earth coordination polymers with aromatic carboxylic acids were used as the precursors of luminescent species, composed with polyethylene glycol (PEG) to achieve inorganic/organic hybrid polymeric dispersing media. The resulting multicomponent hybrid precursors were assembled by an in situ sol–gel process of tert- n-butyl titanate (Ti(OC 4H 9) 4) and further thermal decomposed to obtain two series of rare earth oxysalts phosphors: CaTiO 3:Pr 3+ and Ca(Ti 0.5Zr 0.5)O 3:Pr 3+. Both XRD and SEM indicated the particle sizes of them were in the range of around 1 μm. The excitation spectra presented a broad spectral band in the visible blue-violet region with the maximum excitation peak at 445 nm, while no apparent absorption appeared in ultraviolet region. The corresponding emission spectra showed a wide emission range with a maximum peak at 619 nm, which was ascribed to be the characteristic transition of Pr 3+ ( 1D 2 → 3H 4), which can be expected for visible light conversion materials.

In situ co-precipitation synthesis and luminescence of GdVO 4: Eu 3+ and Y xGd 1 − xVO 4: Eu 3+ microcrystalline phosphors derived from the assembly of hybrid precursors

GdVO 4: Eu 3+ and Y x Gd 1 − x VO 4: Eu 3+ phosphors have been synthesized by a new wet-chemical method named as in situ co-precipitation from multicomponent hybrid precursors. Their microstructure and micromorphology have been analyzed by X-ray powder diffraction (XRD) and scanning electronic microscope (SEM), which indicates that there exist some novel cobblestone-like microcrystalline particles, especially for GdVO 4: Eu 3+. The optical characteristic of Y x Gd 1 − x VO 4: Eu 3+ presents that the luminescence intensity reaches the strongest when the molar ratio of Y/Gd is 0.4/0.6 among x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and the phosphor particles show a strong red emission at 618 nm originating from the hypersensitive transition 5D 0 → 7F 2 of Eu 3+ ions.

In situ chemical coprecipitation composition of hybrid precursors to synthesize YP xV 1− xO 4:Eu 3+ micron crystalline phosphors

In the context, a novel synthesis technology was applied to YP x V 1− x O 4:Eu 3+ phosphors. Among rare earth coordination polymers with aromatic carboxylic acids were used as the precursors of rare earth oxide components, and polyethylene glycol (PEG) and different molar ratio of ammonium vanadate (NH 4VO 3) and ammonium primary phosphate (NH 4H 2PO 4) were composed to assemble inorganic/organic hybrid polymeric dispersing media by an in situ chemical coprecipitation process. After the heat-treatment of the resulting multicomponent hybrid precursors at 1100 °C, YP x V 1− x O 4:Eu 3+ phosphors were achieved. Both XRD and SEM indicated the particles present good crystalline state, whose crystalline grain sizes were in the range of around 0.5–1 μm. The excitation spectra show a brand spectral band in narrow ultraviolet region of 200–280 nm, while no apparent absorption appears in long-wavelengths region of 280–400 nm. The corresponding emission spectra indicate that these crystalline phosphors exhibit very strong red emission of the characteristic transitions of Eu 3+ ( 5D 0 → 7F 2). This technology can be expected to apply to prepare high efficient micron rare earth oxylates (vanadates, phosphates or their complex phosphors) for practical development in luminescent materials and devices.

In situ sol–gel composition of multicomponent hybrid precursors to luminescent novel unexpected microrod of Y 2SiO 5:Eu 3+ employing different silicate sources

Y 2SiO 5 doped with Eu 3+ were in situ synthesized by a hybrid precursor assembly sol–gel technology employing four different silicate sources, 3-aminopropyl-trimethoxysilane (APMS), 3-aminopropyl-triethoxysilane (APES), 3-aminopropyl-methyl-diethoxysilane (APMES) and tetraethoxysilane (TEOS), respectively. The SEM result shows that there exist some novel unexpected morphological microrod structures owing to using the crosslinking reagents other than TEOS as silicate source. The photoluminescent properties of Y 2SiO 5:Eu 3+ have been studied as a function of Eu 3+ doping concentration. A cross-relaxation process between identical Eu 3+ ions results in the quenching of the 5D 1 emission for high concentration sample.

Matrix-inducing synthesis and luminescence of novel unexpected coral-like morphology Mg2Gd8(SiO4)6O2:Tb3+ nanophosphor from in situ composing multicomponent hybrid precursors

Mg2Gd8(SiO4)6O2 doped with Tb3+ was in situ synthesized by a novel hybrid precursors assembly sol–gel technology. The particle size of luminescent materials is in the range of 60–100 nm characterized by XRD and especially SEM shows that there exist some novel unexpected morphological structures owing to multicomponent hybrid precursors. The photoluminescence property of Mg2Gd8(SiO4)6O2:Tb3+ was compared to investigate as a function of Tb3+ ions concentration, which revealed that these nanophosphors showed a strong green emission from 5D4 to 7F5 at 543 nm.