WO2009046392A1 - Synthèse de nanoluminophores à conversion ascendante dopés aux terres rares biofonctionnalisés - Google Patents

Synthèse de nanoluminophores à conversion ascendante dopés aux terres rares biofonctionnalisés Download PDF

Info

Publication number
WO2009046392A1
WO2009046392A1 PCT/US2008/078870 US2008078870W WO2009046392A1 WO 2009046392 A1 WO2009046392 A1 WO 2009046392A1 US 2008078870 W US2008078870 W US 2008078870W WO 2009046392 A1 WO2009046392 A1 WO 2009046392A1
Authority
WO
WIPO (PCT)
Prior art keywords
nanophosphors
rare earth
tri
sio
doped
Prior art date
Application number
PCT/US2008/078870
Other languages
English (en)
Inventor
Yiguang Ju
Jingning Shan
Original Assignee
Trustees Of Princeton University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Trustees Of Princeton University filed Critical Trustees Of Princeton University
Publication of WO2009046392A1 publication Critical patent/WO2009046392A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
    • C09K11/7772—Halogenides
    • C09K11/7773—Halogenides with alkali or alkaline earth metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites

Definitions

  • This invention relates to low temperature methods for producing essentially pure hexagonal phase upconverting fluoride nanophosphors doped with rare earth elements.
  • nanoparticle technology has become a research focus as its fundamental and practical importance becomes more widely known, especially in the case of luminescent materials.
  • upconverting nanophosphors such as rare earth doped phosphorescent oxide salt particles
  • An example would be quantum confinement effects, which brings electrons to higher energy levels, leading to novel optoelectronic properties.
  • Nanoparticles are also finding use in optical, electrical, biological, chemical, medical and mechanical applications and can be found in television sets, computer screens, fluorescent lamps, lasers, etc.
  • Low temperature methods such as sol-gel and homogenous precipitation, have also been used to synthesize upconverting nanophosphors .
  • upconverting nanophosphors synthesized using sol-gel techniques have low crystallinity and require post- treatment or annealing at high temperature to crystallize.
  • an annealing step at a temperature of from about 900 to about 1300 0 C for about six hours or more is required to achieve uniform ion incorporation and increase efficiency.
  • the annealing step, as well as the afore-mentioned high temperature processes can increase particle size through agglomeration and also result in contamination.
  • low temperature processes for producing nanophosphors tend to lead to non-uniform ion incorporation, resulting in low quenching limit concentrations, at best between about 5 mol% and about 7 mol%.
  • the non-uniform ion incorporation produces variations in the distance between dopant ions, with some ions so close that ion-ion interactions produce quantum quenching. This increases as ion concentration increases until a concentration is reached above which decreased fluorescence results. This is defined as the quenching limit concentration.
  • upconverting fluoride nanophosphors are hydrophobic, they need to be modified to be hydrophilic to be useful for biological applications.
  • the conversion of hydrophobic upconverting fluoride nanophosphors to hydrophilic ones without particle agglomeration remains challenging.
  • the present invention addresses these needs by providing processes for producing fluoride nanoparticles with more uniform ion incorporation having higher quenching limit concentrations .
  • the inventive methods make possible the low-temperature preparation of activated hydrophilic hexagonal phase rare earth doped fluoride particles on a nano-scale with uniform spherical size. Furthermore, the inventive methods are also effective over a wide reaction temperature window.
  • UCNPs rare earth doped monodisperse, hexagonal phase fluoride upconverting nanophosphors
  • the methods dissolve one or more rare earth element dopant precursor compounds and one or more host metal fluoride compounds in a solvent comprising a tri-substituted phosphine or tri-substituted phosphine oxide to form a solution; heating the solution to a temperature above 250 0 C at which the phosphine or phosphine oxide remains liquid and does not decompose; and precipitating and isolating from the solution hexagonal phase monodisperese nanophosphors of the host metal fluoride host doped with one or more rare earth elements.
  • the rare earth precursor compound is an organometallic rare earth complex having the structure: RE ( X ) 3
  • RE is a rare earth element and X is an organic ligand.
  • X is a trifluoroacetate ligand.
  • RE is yttrium, holmium, ytterbium, erbium or thulium.
  • host metal compounds are selected so the resulting hosts are in the form of fluorides or oxyfluorides of host metals .
  • the solution contains a phosphine phosphine oxide.
  • the phosphine oxide is trioctyl-phosphine oxide (TOPO) and the temperature is between about 250 0 C and about 400 0 C. According to another embodiment, the temperature is between about 315 0 C and about 370
  • the solution is heated to temperature over a period of about 10 to about 15 minutes.
  • the nanophosphors are precipitated by the addition of a polar solvent with cooling.
  • the polar solvent is an alcohol.
  • hexagonal phase mono-disperse fluoride nanophosphors of a host metal compound doped with one or more rare earth elements are provided, which have been prepared by the method of the present invention.
  • the particles provided by the inventive method have a monodisperse particle size between about 5 and about 200 nm.
  • the particles provided by the inventive method have a monodisperse particle size less than about 20 nm, such as between about 5 and about 20 nm, between about 5 and about 15 nanometers, between about 5 and about 10 nanometers, or between about 10 and about 15 nanometers.
  • the nanoparticles have a quantum quenching concentration above about 10 mol%.
  • methods for coating fluoride upconverting nanophosphors doped with one or more rare earth elements are provided. These inventive methods are advantageous over previously known methods in that they enable modification of upconverting nanophosphors without particle agglomeration.
  • Such methods comprise dispersing fluoride upconverting nanophosphors doped with rare earth elements in a non-polar solvent; forming a water-in-oil microemulsion comprising the upconverting nanophosphor dispersion, a surfactant, and a tetra-alkyl orthosilicate ; hydrolyzing the tetra-alkyl orthosilicate to initiate growth of an SiO 2 layer on the nanophosphors; and destabilizing the microemulsion to precipitate upconverting nanophosphors coated with SiO 2 without forming SiO 2 particles or upconverting nanophosphor particle agglomerates.
  • such methods may also include a step of coating the SiO 2 - coated upconverting nanophosphors with a layer of an amino group- functional compound so that reactive amino groups are on the
  • Fig. Ia Presents a TEM image of Er 3+ doped nanoparticles synthesized in TOPO at 340 0 C.
  • Fig. Ib depicts a Histogram of the nanoparticles synthesized in TOPO.
  • Fig. Ic Presents a TEM image of Er 3+ doped nanoparticles synthesized in OM at 334°C.
  • Fig. Id Presents a TEM image of Er 3+ doped nanoparticles synthesized in OA/ODE at 315°C.
  • Fig. 2 Presents an EDS analysis spectrum of the hexagonal ( ⁇ - phase) nanoparticles synthesized in TOPO.
  • Figs. 3a Presents XRD patterns of nanoparticles prepared with different solvents .
  • Fig. 3b Presents XRD patterns of nanoparticles prepared with at different temperatures.
  • Fig. 4a Presents TEM images of the nanoparticles prepared in TOPO at 360 0 C.
  • Fig. 4b Presents TEM images of the nanoparticles prepared in TOPO at 360 0 C.
  • the inset scale bar 5 nm.
  • Fig. 4c Presents a selected-area electron diffraction pattern of the sample in Fig. 4a showing six of the diffraction rings corresponding to the hexagonal NaYF 4 lattice.
  • Fig. 5a Presents TEM images of samples reacted at 380 0 C for 30 min .
  • Fig. 5b Presents TEM images of samples reacted at 380 0 C for 50 min.
  • Fig. 5c Presents TEM images of samples reacted at 380 0 C for 70 min.
  • Fig. 5d Presents TEM images of samples reacted at 380 0 C for 90 min.
  • Fig. 6 Presents upconversion fluorescence spectra of Er 3+ doped nanoparticles synthesized in different solvents.
  • Fig. 7a Presents TEM images of NaYF 4 :Yb,Ho
  • Fig. 7b Presents TEM images of NaYF 4 :Yb,Tm.
  • Fig. 7c Presents Upconversion fluorescence spectra of NaYF 4 : Yb, Ho and NaYF 4 : Yb, Tm.
  • Fig. 9 Presents XRD patterns of the nanoparticles prepared in OA/TOP/ODE solvents at different OA/TOP ratios.
  • Fig. 10 Presents a schematic illustration of the phase transition due to the change of energy barrier via the oleate-TOP ligand formation for the synthesis of NaYF 4 : Yb, Ln UCNP.
  • Fig. 12 Presents TEM images (top) of the SiO 2 coated
  • NaYF 4 :Yb,Er UCNPs (a) ⁇ -phase and b) ⁇ -phase, and their UC emission spectra (bottom) before and after coating, (c) presents comparison of UC emission spectra of the uncoated ⁇ -phase and ⁇ -phase nanoparticles.
  • Fig. 13a Presents TEM images of OA/TOP coated nanoparticles.
  • Fig. 13b Presents TEM images of SiO 2 coated UCNPs and SiO 2 particles .
  • Fig. 13c Presents TEM images of clean SiO 2 coated nanoparticles.
  • Fig. 14a Presents EDS results of UCNPs before SiO 2 coating.
  • Fig. 14b Presents EDS results of UCNPs after SiO 2 coating.
  • Fig. 15 Presents upconversion emission spectra of the initial nanoparticles (a), and after coating amino (b) and carboxyl (c) groups .
  • UCNPs phosphorescent rare earth doped fluoride upconverting nanoparticles
  • UCNPs upconverting phosphorescent nanoparticles or upconverting nanophosphors (UCNPs) or nanocrystals (NCs)
  • UCNPs upconverting phosphorescent nanoparticles
  • NCs nanocrystals
  • Employing various embodiments of the present invention produces monodisperse (non-aggregated), hexagonal phase fluoride nanoparticles with a controllable size and morphology with a smooth surface and uniform distribution of rare earth dopant ions.
  • a precursor solution is prepared by dissolving one or more rare earth precursor compounds and one or more host metal fluoride compounds in a tri-substituted phosphine .
  • the molar ratio of host metal fluoride compound to rare earth precursor compound is between about 95:5 and about 70:30, and preferably between about 90:10 and about 75:25.
  • the stoichiometric amounts of host metal fluoride compound and rare earth precursor compound remain essentially the same, so that a 78:22 starting ratio of host compound to rare earth compound will result in a particle containing 22 mol% rare earth element ions .
  • the rare earth precursor compounds include, but are not limited to, organometallic rare earth complexes having the structure :
  • RE is a rare earth element and X is an organic ligand.
  • X is a monofunctional ligand.
  • a single trifunctional organic ligand can be used, as well as a difunctional ligand in combination with a monofunctional ligand, in which case the depicted stoichiometry will be modified accordingly.
  • rare earth as used herein includes scandium, yttrium, and the fifteen lanthanoids .
  • Strontium can also be used, and for purposes of the present invention, rare earth elements are defined as including strontium. Any rare earth element or combinations thereof can be used (i.e., europium, cerium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, etc.), with yttrium, holmium, ytterbium, erbium, thulium and mixtures thereof being preferred.
  • Suitable organic ligands include, but are not limited to, ligands such as trifluoroacetate, tetramethylheptanedionate, iso- propoxide and the like. Trifluoroacetate (CF 3 COO-) is a preferred organic ligand.
  • (CF 3 COO) 3 RE precursors are prepared by dissolving corresponding rare earth oxides in trifluororacetic acid and heating at reflux temperature. After clear solutions are obtained, the solvent is removed under vacuum and the resulting solids are dried.
  • the host metal fluoride compounds are selected so the resulting hosts are in the form of fluorides or oxyfluorides of the host metals.
  • Suitable host metals include, but are not limited to, lanthanum, yttrium, lead, zinc, cadmium, sodium and any Group II metals such as, beryllium, magnesium, calcium, strontium, barium and any mixtures thereof.
  • the solvent used to prepare the precursor solution contains a tri-substituted phosphine or tri-substituted phosphine oxide.
  • Tri- substituted phosphines and phosphine oxides suitable for use with the present invention remain liquid and do not decompose at a temperature above about 250 0 C.
  • Suitable compounds include, but are not limited to, trialkylphosphines and trialkylphosphine oxides such as trioctylphosphine oxide (TOPO), trioctylphosphine (TOP), tripropylphosphine, tripropylphosphine oxide, tri-n-butylphosphine, tri-n-butylphosphine oxide, tri-t-butylphosphine, tri-t-butyl- phosphine oxide, and the like.
  • TOPO trioctylphosphine oxide
  • TOP trioctylphosphine
  • tripropylphosphine tripropylphosphine oxide
  • tri-n-butylphosphine tri-n-butylphosphine oxide
  • tri-t-butylphosphine tri-t-butyl- phosphine oxide
  • Triphenylphosphine and triphenyl- phosphine oxide can also be used, as well as phosphines and phosphine oxides with two or three different organic substituents, provided that the phosphines and phosphine oxides remain liquid and do not decompose at a temperature above about 300 0 C. Phosphine mixtures that remain liquid and do not decompose at temperatures above 300 0 C can also be used.
  • Trioctylphosphine oxide is employed in the preferred embodiments of the instant methods.
  • the solvent may consist essentially of a tri-substituted phosphine or phosphine oxide or include other solvents, such as oleic acid (OA), oleylamine, and noncoordination solvents, such as, octadence (ODE), therminol 66, and the like.
  • the exact content of the solvent may be varied depending on the desired size or shape of the resulting doped nanoparticles .
  • solvent consisting essentially of a tri-substituted phosphine oxide, preferably TOPO may be used to produce doped nanoparticles in the range of about 5 nm to about 20 nm.
  • solvent consisting essentially of a mixture of tri-substituted phosphine, preferably TOP, and OA in a non-coordination solvent, such as, for example, ODE may be used to generate doped nanoparticles in the range of about 20 nm to about 200 nm.
  • OA/TOP the increase of TOP in the ratio of OA to TOP (OA/TOP) favors the transition of nanoparticles from ⁇ phase and ⁇ phase.
  • OA/TOP may range between about 1:1 to about 1:4, with the addition of OA/TOP in high and low ratio producing hexagonal particles and nanorods, respectively.
  • the precursor solution is heated to facilitate formation of doped nanoparticles.
  • the water may be removed from the solution by any known techniques, such as by heating the solution to 100 0 C under vacuum for about 30 minutes.
  • nitrogen may be purged in the solution and the solution may be gradually heated to the targeted temperature.
  • the targeted temperature is below the evaporation, boiling or decomposition temperature of the phosphine, more preferably between about 250 0 C and about 400 0 C, and even more preferably between about 315 0 C and about 370 0 C, and the solution is heated to the targeted temperature over a period of about 10 to about 15 minutes.
  • the doped nanoparticles may be precipitated and isolated by any known method, typically by the addition of a quantity of polar solvent with cooling in an amount effective to render the particles insoluble in the resulting liquid.
  • the reactions may be allowed to proceed for about one hour, after which the solution may be allowed to cool and ethanol may be added to the cooled solution to precipitate the doped nanoparticles.
  • the precipitated nanoparticles may be isolated from the solution by filtering, microf iltering, centrifuging, ultracentrifuging, settling, decanting or a combination of these.
  • the time periods as well as the precipitation and isolation techniques are provided only as an example, and such person will be capable of customizing them depending on the desired results, his or her own experience, and existing literature.
  • UCNP upconverting nanophospors
  • UCNPs suitable for coating by this embodiment of the invention may be prepared by the low temperature precipitation methods disclosed herein, or by any methods known and used in the art for making rare earth doped fluoride nanoparticles .
  • the particle size may be up to one micron. Suitable methods include, but are not limited to, co-thermolysis, thermal hydrolysis, laser heat evaporation, chemical vapor synthesis, microemulsion spray pyrolysis, and pool flame synthesis, and low temperature methods, such as sol-gel and homogenous precipitation.
  • the UCNPs are dispersed or dissolved with agitation in a non- polar solvent to form a non-polar phase.
  • concentration of UCPNs in the non-polar phase ranges between about 50 mg/mL and about 500 mg/mL and preferably between about 100 mg/mL and about 300 mg/ml .
  • Suitable non-polar solvents include, but are not limited to, cyclohexane, toluene, hexane, pentane, isopentane, octane, heptane, and so forth, with cyclohexane being preferred.
  • a water-in-oil microemulsion is formed by adding water and one or more surfactants to the non-polar phase with agitation, after which one or more tetra-alkyl orthosilicates are added to the
  • the concentration of the surfactant in the surfactant solution is sufficient to form a stable microemulsion, and typically ranges between about 0.5 mL and about 10.0 mL per 100 mL of microemulsion and preferably between about 1.0 mL and about
  • the surfactant may be an anionic, cat-ionic, non-ionic or zwitterionic surfactant, and may be a monomeric or polymeric surfactant.
  • a suitable surfactant is NP-9 (nonylphenol ethoxylate), a nonionic polyethoxylated nonylphenol surfactant available from BASF, which may be employed by itself or in combination with one or more other surfactants .
  • the concentration of tetra-alkyl orthosilicate may be between about 0.05 mL and about 1.0 mL per 100 mL of microemulsion and prefer-ably between about 0.1 mL and about .5 mL per 100 mL of microemulsion.
  • Tetra-ethyl orthosilicate is a preferred tetra-alkyl orthosilicate, but others, including, but not limited to, tetra- methyl orthosilicate, tetra-propyl orthosilicate and tetra-butyl orthosilicate, may be used in addition to or instead of tetra-ethyl orthosilicate .
  • the tetra-alkyl orthosilicate is hydrolyzed.
  • the hydrolysis may be catalyzed by a Lewis base, such as dimethylamine (DMA) .
  • the Lewis Base is added in a quantity between about 0.025 mL and about 1.0 mL per 100 mL of microemulsion and preferably between about .05 mL and about .5 mL per 100 mL of microemulsion.
  • the reaction is allowed to proceed for approximately 1 to 24 hours, after which the microemulsion may be destabilized to precipitate UCNPs coated with silicon dioxide.
  • the thickness of the coating will depend upon the amount of tetra-alkyl orthosilicate and the amount of Lewis base added to the microemulsion.
  • the step of destabilizing the microemulsion may comprise adding to the suspension an effective amount of a polar solvent that is miscible with the non-polar solvent phase, the water phase, or both. Suitable examples include, but are not limited to, acetone, ethanol, methanol or some other liquid.
  • the amount of polar solvent effective to destabilize the micoemulsion is used will vary depending on the surfactant and amount of surfactant used but is generally attained simply by using an excess quantity of material .
  • the step may also comprise changing the temperature, for example to a temperature at which the suspension is not stable.
  • the particles precipitate, and may be separated from the destabilized microemulsion by filtering, micro- filtering, centrifuging, ultracentrifuging, settling, decanting or a combination of these.
  • the precipitated UCNPs may be washed with a polar solvent to remove any physically adsorbed molecules from the surface of UCNPs.
  • the resulting silicon dioxide coated hydrophilic UCNPs are suitable for further biofunctionalization .
  • the instant methods may further include a step of covalently attaching amino group-functional compounds to the silicon dioxide coated surface of the UCNPs.
  • such a step may comprise suspending Si0 2 -coated UCNPs in a polar solvent, such as isopropanol, and adding an amino group-functional compound, such as alkylamine organosilane, such as 3-aminopropyltrimethoxy silane (APS), to the suspension.
  • concentration of Si0 2 -coated UCNPs in the polar solvent may range between about 50 mg/mL and about 500 mg/mL and preferably between about 100 mg/mL and about 300 mg/ml .
  • carboxyl groups may be coated onto UCPNs by directly mixing the UCNPs with amphiphilic modified polyacrylic acids (PAA) such as isopropyl amine and octylyamine modified PAA.
  • PAA amphiphilic modified polyacrylic acids
  • the coatings of amino and carboxyl groups onto UCNPs' surfaces enable antibody conjugation for biological applications such as bioimaging and photodynamic therapy.
  • Trioctylphosphine oxide (TOPO) (90%), oleylamine (OM) (70%), octadecene (ODE) (90%), sodium trifluoroacetate (98%) and tri- fluoroacetic acid (CF 3 COOH, reagent grade) were purchased from Sigma-Aldrich .
  • CF 3 COOLn precursors were prepared by dissolving the corresponding lanthanide oxides in trifluoroacetic acid and heating at the reflux temperature. After clear solutions were obtained, the solvent was removed under vacuum. The resulting solids were dried under vacuum at room temperature overnight and used without further purification .
  • Powder x-ray diffractometer (XRD, 30 kV and 20 mA, Cu Ka, Rigaku) was used for crystal phase identification. The powders were pasted on an alumina substrate and the scan was performed in the 2 ⁇ range 10°-70°. The photoluminescence (PL) measurements were performed at room temperature. A 980 nm laser diode (1 W maximum,
  • Lasermate Group, Inc. was used as the excitation source and the beam was focused (12 cm focal length) to a spot size of approximately 0.5 mm.
  • the PL signals were focused to the end of a optical fiber and then delivered into the slit of a monochromator
  • the signal was detected by a photomultiplier module (H6780-04, Hamamatsu Corp.) and was amplified by a lock-in amplifier (SR510, Stanford Research Systems) together with an optical chopper (SR540, Stanford Research Systems) .
  • SR510 Stanford Research Systems
  • SR540 Stanford Research Systems
  • the signal was recorded under computer control using the SpectraSense software data acquisition/analyzer system (Princeton Instruments ) .
  • TEM Transmission electron microscope
  • HRTEM high-resolution TEM
  • LEO/Zeiss 910 TEM equipped with a PGTIMIX EDX system (100 keV) and Philips CM200 FEGTEM equipped with a Gatan 678 Imaging Filter and a PGT-IMIX EDX system.
  • this microscope provides a point-to- point resolution of 0.2 nm, and an electron probe of 0.7 nm with an energy up to 200 keV, respectively.
  • the energy dispersive spectrometer (EDS) analysis was performed using a FEI XL30 FEG-SEM (scanning electron microscope) equipped with a PGT-IMIX PTS EDX system.
  • the IH NMR spectrum was collected with Varian Inovas 500 MHz spectrometers.
  • the calculated compositions of the nanocrystals from the precursor concentrations were NaYF 4 : Yb 0 . 33 Er 0 .03 • TEM images of the NCs synthesized in different solvents are shown in Figs. la-Id. These figures were generated based on 200 randomly selected particles.
  • the NCs synthesized in TOPO (340 °C) had a very narrow size range from 7.8 to 11.1 nm with an average size of 9.2 nm and standard deviation ( ⁇ ) of 0.73 (Figs. Ia, b) .
  • the NCs synthesized in OM had a broad particle size distribu-tion in the range from 7 to 20 nm with an average size of about 10 nm (Fig. Ic) .
  • the broad particle distribution shown in Fig. Ic was the outcome of the aggregation process indicative of inefficient OM ligand protection.
  • the OM heating (reflux) could also contribute to the reduced coordination properties of OM.
  • the NCs synthesized in ODE/OA had the largest particle sizes (Fig. Id), ranging from 15 to 40 nm with an average size of 25 nm, and they had irregular shapes.
  • the TEM results indicate that the NCs prepared in TOPO have a highly monodisperse particle size distribution.
  • the atomic composition ratios of NCs synthesized in TOPO were determined by EDS analysis.
  • Fig. 2 shows one EDS spectrum.
  • Inset table 1 shows the measured atomic ratios of the elements
  • inset table 2 shows the calculated and measured values of the lanthanides.
  • the measured lanthanide atomic ratios and Na/Ln ratio (0.90) are very close to the calculated values. Since EDS is a semi-quantitative analysis method which is significantly affected by the surface properties of the sample, it is not a surprise that atomic% of fluoride is smaller than the calculated value.
  • XRD x-ray diffraction
  • the XRD patterns of the corresponding NCs in Figs. la-Id are shown in Figs, a and b.
  • the NCs prepared from ODE/OA presented pure Qf-phase, which agreed well with the literature results.
  • the NCs prepared from OM (334 °C) exhibited mixed a- and /3-phases, while the NCs prepared in TOPO, as shown in Fig. 3b, had diffraction peaks matching well with the /3-phase NaYF 4 JCPDS data (card 28- 1192); thus pure /3-phase NCs resulted at 340 °C.
  • the peaks due to (110) and (100) reflections overlapped, which could be ascribed to the small NC particle size.
  • the NCs obtained in TOPO showed the dominant /3- phase, while the NCs synthesized in OM and OA/ODE had dominant Qf- phase, which indicated that the energy barrier of the a ⁇ ⁇ phase transition was reduced significantly in TOPO compared with other available solvents/ligands, and led to the formation of the more efficient /3-phase NCs and smaller NC particles.
  • the /3-phase NCs were obtained in a much wider temperature window.
  • the UCNPs can be prepared at an even higher temperature in this work. Another sample prepared at 360 °C is shown in Figs. 4a-4c.
  • Fig. 4a shows the TEM image of the UCNPs synthesized at 360 °C.
  • the HRTEM image in Fig. 4b shows the crystalline fringes of the NCs.
  • the selected-area electron diffraction (SAED) pattern, presented in Fig. 4c, shows spotty polycrystalline diffraction rings corresponding to the (100), (110), (111), (201), (311), and (321) planes of the /3-phase NaYF 4 lattice.
  • SAED selected-area electron diffraction
  • the high-limit temperature impact on NCs produced in TOPO solvent was investigated by increasing the reaction temperature to as high as 380 0 C. With the progress of heating the precursors in TOPO solvent, first the appearance of gas bubbles was observed at about 240 °C, which indicated the decomposition of the metal trifluoroacetates ; meanwhile, the solution turned from colorless into yellowish.
  • the breakdown of the crystals corresponded with the appearance of large amounts of smoke at the temperature of 380 0 C, which was most probably related to the decomposition of the TOPO solvent at elevated temperature.
  • the role of TOPO was to provide surface binding and spatial restriction on the NCs to ensure monodispersed growth of the /3-phase NCs. If the temperature was too high, the TOPO binding on the crystal surface was unstable due to TOPO decomposition. Therefore, TOPO lost its ligand property and the naked crystals further underwent aggregation in a similar way as in gas phase synthesis.
  • Fluorescence spectra of the three NCs are shown in Fig. 6. There were three emission peaks at 520.8, 545 and 658.8 nm, which were assigned to the 4 Hn/ 2 4I ( i 5/2 ), 4 S 3/2 - 4 Iis / 2 and 4 F 9/2 - 4 Ii5 / 2 transitions for Er3+, respectively.
  • the NCs prepared in TOPO present the brightest fluorescence compared with the NCs synthesized from ODE/OA and OM solvents.
  • the NCs synthesized from TOPO show about 20 times higher emission intensity than those prepared from ODE/OA.
  • the /3-phase NCs synthesized from TOPO only show about two times higher emission intensity than the NCs synthesized from OM. Part of the reason is because there are large /3-phase NCs (>20 nm) mixed in those NCs with a broad size distributed as shown in Fig. Ic.
  • the upconversion fluorescence of lanthanide ion doped NCs is related to the particle size: generally, the larger the particle size, the higher the photo- luminescence.
  • the difference in the particle size distribution between the NCs synthesized from OM and TOPO can be further compared by the emission peak at the wavelength 658.8 nm. A sharp narrow emission peak is shown for the NCs synthesized from TOPO, while a broad shoulder for the NCs synthesized from OM is presented.
  • TEM images of Ho 3+ -doped and Tm 3+ -doped NCs are shown in Figs . 7a and 7b, in which the average particle sizes are 11 and 10 nm, respectively.
  • the UP fluorescence spectra excited at 980 nm are shown in Fig. 7c.
  • Spectral bands corresponding to blue, green and red emission transitions of Ho 3+ and Tm 3+ are clearly depicted in the spectra.
  • the mechanisms responsible for the UP fluorescence including those shown in Figs. Ia-Ic have been explained in detail in the literature.
  • Example 2 Particle Preparation in oleic acid OA and trioctyl- phosphine (TOP) in (ODE) .
  • the Na/Ln molar ratio was fixed at 1.6.
  • Experiments were conducted for various OA/TOP/ODE solvents by varying the OA/TOP ratios.
  • the size distribution and crystal structure of the as-synthesized particles were characterized by using the transmission electron microscopy TEM and x-ray diffraction XRD measurements.
  • Fig. 8(a-e) shows the TEM images of the as-synthesized NaYF 4 :Yb 33%, Er 3% UP-NCs at different OA/TOP ratios.
  • the corresponding XRD patterns are shown in Fig. 9.
  • the ⁇ -phase and ⁇ -phase crystalline structures were determined from NaYF4 JCPDS data for ⁇ - phase Ref. 29 and ⁇ -phase Ref. 30, and were also compared with the literature results .
  • Fig. 8(a-e) show that an a ⁇ phase transition occurred with the increase of the TOP in OA/TOP ratios.
  • the XRD patterns in Fig. 9 demonstrate that the crystal phase changed from pure ⁇ in OA/ODE to mixed phases and pure ⁇ in OA/TOP/ODE, and back to pure ⁇ in TOP/ODE.
  • NCs synthesized in TOP/ODE solvents without OA remained in the phase ⁇ , as shown in Fig. 9 (graph (e)), excluded the possibility that the TOP ligand reduced the energy barrier for the a ⁇ phase transition.
  • Fig. 8 (b) The coexistence of the small ⁇ -phase NCs with the large ⁇ - phase NCs in Fig. 8 (b) indicates that the phase transition occurred at the same time as the Ostwald ripening.
  • the samplings at the reaction time of 30 min were collected from solvents at OA/TOP ratios of 1:1 and 1:4.
  • the corresponding TEM images of these samples are shown in Figs. 11 (a-b) .
  • Fig. ll(a-b) it is seen that fewer large particles were formed by consuming many small ones, which is the typical Ostwald-ripening process for large particle growth.
  • the /3-phase hexagonal nanoparticles were obtained in a broad range from 50 to 200 nm.
  • a further increase of the TOP/OA ratio led to the forma-tion of the rod-shape NCs. Therefore, an addition of TOP ligand into OA provided a different pathway other than changing precursor ratios to synthesize the /3-phase NCs with tunable size and shape.
  • NaYF 4 : Yb, Tm and NaYF 4 : Yb, Ho NCs were been prepared using the same method.
  • Example 3 Coating Nanoparticles with Silicon Oxide
  • a silica layer was coated onto the oleate and oleate/TOP capped ⁇ -phase and /3-phase NCs produced in Example 2. See “Controlled Synthesis of Lanthanide-doped NaYF 4 Upconversion Nanocrystals via Ligand Induced Crystal Phase Transition and Silica Coating,” Appl . Phys . Lett., 91 (2007) .
  • Fig. 12 shows the TEM images of the silica coated NCs: (a) the ⁇ -phase NaYF 4 : Yb, Er synthesized in OA/ODE and (b) the /3-phase NaYF 4 : Yb, Er synthesized in OA/TOP/ODE solvents at unity OA/TOP ratio.
  • Upconversion emission spectra of the corresponding NCs before and after coating is shown in Fig. 12 (c) . It is seen that for small NCs in the ⁇ -phase, silica coating leads to a dramatic reduction of luminescence intensity. However, for the /3-phase NCs, silica coating almost does not affect the luminescence intensity and spectra, except in the green region.
  • the reason for the luminescence reduction for small NCs was evaluated by the volume ratio of the SiO2 coating layer to the particle.
  • the average thickness of the silica layers is 17 and 8 nm, respectively, and the approximate volume ratios between the coating layers and particles are 50 and 1.5, respectively.
  • the much larger silica to crystal volume ratio in sample in Fig. 12 (a) indicates that the ion density is decreased significantly when the outside coating thickness is comparable to the particle diameter, which results in the significant reduction of luminescence.
  • the small silica to crystal volume ratio causes less change in ion density, and thus the silica layer has less effect on luminescence intensity.
  • the emission peaks at 520.8, 545, and 658.8 nm of the Er doped NCs were due to 4 i ⁇ n/ 2 to 4 Ii5/2, 4 S 3 / 2 to 4 Ii5/2, and 4 F 9/2 to 4 Iis/2 transitions for Er 3+ , respectively.
  • the luminescence intensity of green emission was reduced more significantly than that of red emission before and after the silica coating. The reason is because the green emission is a three-photon process which is more sensitive to the reduction of the excitation intensity than the two-photon red emission.
  • the emission intensities for green and red emissions are, respectively, proportional to the cubic and square of the excitation intensity.
  • UC-NCs the quantum efficiency of UC-NCs strongly depends on the particle crystal size. Large particles will deliver stronger luminescence.
  • the UC emission spectra of the uncoated ⁇ -phase and /3-phase NCs are compared in Fig. 12 (c) . It is clearly seen that the large /3-phase NCs have much stronger emission intensity than that of the ⁇ -phase NCs.
  • both ⁇ -phase and /3-phase NCs could be suspended in polar solvents such as ethanol for a very long time, which would be suitable for further biofunctionalization .
  • Example 4 Coating Nanoparticles with Silicon Oxide and Amino- Functional Group Compounds . Materials and Methods:
  • the silica coated upconverting nanophospors were prepared based on the method developed by Darbandi et al . , "Silica encapsulation of hydrophobically ligated PbSe nanocrystals, " Langmuir, 22, 4371 - 5, (2006) with two modifications.
  • First NP-9 was used instead as the surfactant of NP-5 and secondly, due to the low solubility of UCNPs in cyclohexane, there was no stock solution being prepared, while a long sonification time was needed to disperse the UCNPs before the silica coating.
  • OA-TOP capped UCNPs were dissolved in 100 mL cyclohexane by sonicating 30 min, then 2 mL NP-9 and 0.1 mL TEOS were added which were followed by vigorous stirring for 30 min to form water-in-oil (W/0) microemulsion system.
  • 50 - 100 ⁇ L DMA was then added to initiate hydrodrolysis of TEOS to form an SiO 2 layer onto the UCNPs.
  • the SiO 2 growth was stopped after 12- 24 hours reaction.
  • the nanoparticles were destabilized from the microemulsion using ethanol and precipitated by centrifugation .
  • UCNP/SiO 2 composite particles were washed with absolute ethanol three times. For each washing step, followed by centrifugation, a sonicator bath was used to completely disperse the precipitate in the ethanol and remove any physically adsorbed molecules from the particle surfaces. Finally, UCNP/SiO 2 nanoparticles, which were dispersable in ethanol and water, were obtained.
  • Carboxyl coated UCNPs were obtained by mixing as-synthesized UCNPs with octylamine and isopropylamine modified PAA directly.
  • the modified PAA was prepared in a similar way to that in Gohon et al . ,
  • HOS human osteosarcoma cells
  • ATCC Manassas, VA
  • VA human osteosarcoma cells
  • the HOS cells were cultured in 25 cm 2 flasks (Becton-Dickinson, Franklin Lakes, NJ) and maintained in an incubator at an incubation temperature of 37 0 C regulated with 5% CO 2 , 95% air, and saturated humidity.
  • DMEM Dulbecco's Modified Eagle Medium
  • a cell suspension at a concentration of approximately 5xlO 4 cells/ml was then prepared, as determined by a hemocytometer count.
  • the cells were seeded into the 24-well culture plate, 10 4 cells (200 ⁇ L x 5xlO 4 cells/ml) in each well.
  • 50 ⁇ L of UCNP solution was added to each of 3 wells and kept at 37 0 C in a fully humidified atmosphere at 5% CO 2 in air.
  • the cells were grown as a monolayer and fixed for 2.5 hr with 2% glutaraldehyde in 0.2 M sodium cacodylate buffer, pH 7.2, rinsed with 0.2 M sodium cacodylate buffer, pH 7.2, post-fixed with 1% OsO 4 in sodium veronal buffer, for one hour at about 4 0 C, rinsed with sodium veronal buffer.
  • reversed micelles were formed by water nano- droplets in an organic medium and further used for synthesis or surface modification of nanoparticles .
  • the formation of SiO 2 starts from the hydrolysis of TEOS at the oil/water interface catalyzed by bases such as dimethylamine (DMA) .
  • bases such as dimethylamine (DMA) .
  • the hexagonal phase UCNPs usually have larger particle sizes (-100 nm) and less solubility in organic solvent.
  • OA/TOP capped UCNPs can be dissolved in hexane to form a stable solution, but the solution is not transparent.
  • Figs. 13a-13c depict TEM images of as-synthesized UCNPs and products of SiO 2 encapsulation in the presence of DMA as catalyst for TEOS polymerization.
  • DMA catalyst for TEOS polymerization.
  • the same amounts of original UCNPs, NP - 5, DMA and TEOS were used with 40 mg, 2 mL, 100 ⁇ L, and 0.12 mL, respectively.
  • the amounts of solvent and cyclohexane were 25 mL and 50 mL, respectively.
  • amino functionalization was performed by reacting UCNP/SiO 2 with APS.
  • carboxyl group functionalization was achieved by mixing amphiphilic modified PAA with the hydrophobically ligated NCs. After the addition of carboxyl groups with amphiphilic PAA coating, it was confirmed that the hydrophobic UCNPs becomes disperable in water.
  • Fig. 15 shows the comparisons of the emission spectra of the UCNPss before and after coating the amino and carboxyl groups with a NIR excitation at 980 nm.
  • Our results showed that both amino/Si0 2 coatings and the direct carboxyl coating have very little effect on the emission intensity.
  • the coatings of amino and carboxyl groups onto UCNP surface enable specific antibodies conjugation for biological applications. The little change of luminescence intensity is a promising result for the application of UCNPs for bioimaging and photodynamic therapy.
  • the data of cytotoxicity and the ability of biocompatibility of the functionalized UCNPs are the two important factors and need to be obtained.
  • the cell toxicity and the cell uptake were investigated by incubating the above functionalized UCNPs with human osteosarcoma cells. The toxicity and the cell uptake results are shown in Fig. 5 and Fig. 6, respectively.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Nanotechnology (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Composite Materials (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Luminescent Compositions (AREA)

Abstract

La présente invention concerne des procédés pour préparer des nanoluminophores à conversion ascendante, à phase hexagonale, monodispersés et dopés aux terres rares, dont les étapes consistent à : dissoudre un ou plusieurs composés précurseurs de terres rares et un ou plusieurs composés de fluorure métallique hôte dans un solvant contenant une phosphine trisubstituée ou un oxyde de phosphine trisubstitué pour former une solution ; chauffer la solution à une température supérieure à environ 250 °C, à laquelle la phosphine ou l'oxyde de phosphine reste liquide et ne se décompose pas ; et précipiter et isoler des nanoparticules monodispersées à phase hexagonale phosphorescentes en solution, le composé métallique hôte dopé avec un ou plusieurs éléments du groupe des terres rares. L'invention concerne également des nanoparticules selon la présente invention et des procédés pour revêtir avec du SiO2 des nanoluminophores à conversion ascendante dopés aux terres rares.
PCT/US2008/078870 2007-10-04 2008-10-04 Synthèse de nanoluminophores à conversion ascendante dopés aux terres rares biofonctionnalisés WO2009046392A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US97763307P 2007-10-04 2007-10-04
US60/977,633 2007-10-04
US32000308P 2008-02-02 2008-02-02
US61/320,003 2008-02-02

Publications (1)

Publication Number Publication Date
WO2009046392A1 true WO2009046392A1 (fr) 2009-04-09

Family

ID=40526716

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2008/078870 WO2009046392A1 (fr) 2007-10-04 2008-10-04 Synthèse de nanoluminophores à conversion ascendante dopés aux terres rares biofonctionnalisés

Country Status (1)

Country Link
WO (1) WO2009046392A1 (fr)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010006280A1 (de) 2010-01-30 2011-08-04 Merck Patent GmbH, 64293 Farbkonvertierung
WO2011147521A1 (fr) 2010-05-27 2011-12-01 Merck Patent Gmbh Conversion d'abaissement
WO2012010238A1 (fr) 2010-07-17 2012-01-26 Merck Patent Gmbh Amélioration de la pénétration et de l'action
CN102533272A (zh) * 2010-12-24 2012-07-04 中国科学院福建物质结构研究所 一步法合成水溶性的氨基化稀土掺杂氟化钇钠纳米颗粒
CN103436263A (zh) * 2013-09-09 2013-12-11 天津师范大学 水溶性红绿光可调谐的稀土掺杂上转换纳米材料的制备方法
CN103952138A (zh) * 2014-04-30 2014-07-30 深圳清华大学研究院 上转换复合材料及其制备方法、太阳能电池
CN103980904A (zh) * 2014-03-27 2014-08-13 中国科学院福建物质结构研究所 一种氟化钇锂纳米复合材料及其制备方法和在光动力学治疗中的应用
US9012869B2 (en) 2009-05-05 2015-04-21 Lumito Ab System, method, and luminescent marker for improved diffuse luminescent imaging or tomography in scattering media
WO2016016134A1 (fr) * 2014-07-28 2016-02-04 Koninklijke Philips N.V. Boîtes quantiques revêtues de silice à rendement quantique amélioré
EP2621736A4 (fr) * 2010-10-01 2016-03-02 Intelligent Material Solutions Inc Particules monodispersées uniformes en morphologie et en taille et leur auto-assemblage dirigé par la forme
CN105963697A (zh) * 2016-05-31 2016-09-28 陕西师范大学 基于荧光共轭聚合物与上转换纳米材料的复合抗菌剂及其使用方法
WO2017125951A1 (fr) * 2016-01-22 2017-07-27 Council Of Scientific And Industrial Research Microtiges de conversion ascendante à base de lanthane et leurs applications
CN107163944A (zh) * 2017-06-26 2017-09-15 大连理工大学 一种调控稀土上转换纳米材料形貌的共掺杂金属离子的制备方法
CN112903733A (zh) * 2021-01-25 2021-06-04 中国科学院广州地球化学研究所 一种透射电镜能谱超分辨分析方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6576291B2 (en) * 2000-12-08 2003-06-10 Massachusetts Institute Of Technology Preparation of nanocrystallites
US20060234417A1 (en) * 2002-07-16 2006-10-19 Tetsuhiko Isobe Composite nanoparticle and process for producing the same
US7175778B1 (en) * 2002-05-10 2007-02-13 Nanocrystals Technology Lp Self-aligning QCA based nanomaterials
US20070113779A1 (en) * 2005-11-02 2007-05-24 The Research Foundation Of State University Of New York Metal oxide and metal fluoride nanostructures and methods of making same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6576291B2 (en) * 2000-12-08 2003-06-10 Massachusetts Institute Of Technology Preparation of nanocrystallites
US7175778B1 (en) * 2002-05-10 2007-02-13 Nanocrystals Technology Lp Self-aligning QCA based nanomaterials
US20060234417A1 (en) * 2002-07-16 2006-10-19 Tetsuhiko Isobe Composite nanoparticle and process for producing the same
US20070113779A1 (en) * 2005-11-02 2007-05-24 The Research Foundation Of State University Of New York Metal oxide and metal fluoride nanostructures and methods of making same

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9012869B2 (en) 2009-05-05 2015-04-21 Lumito Ab System, method, and luminescent marker for improved diffuse luminescent imaging or tomography in scattering media
DE102010006280A1 (de) 2010-01-30 2011-08-04 Merck Patent GmbH, 64293 Farbkonvertierung
WO2011091946A1 (fr) 2010-01-30 2011-08-04 Merck Patent Gmbh Dispositif électroluminescent organique comportant une couche intégrée pour la conversion de couleurs
WO2011147521A1 (fr) 2010-05-27 2011-12-01 Merck Patent Gmbh Conversion d'abaissement
WO2012010238A1 (fr) 2010-07-17 2012-01-26 Merck Patent Gmbh Amélioration de la pénétration et de l'action
US9758724B2 (en) 2010-10-01 2017-09-12 Intelligent Material Solutions, Inc. Morphologically and size uniform monodisperse particles and their shape-directed self-assembly
US10273407B2 (en) 2010-10-01 2019-04-30 Intelligent Material Solutions, Inc. Morphologically and size uniform monodisperse particles and their shape-directed self-assembly
EP2621736A4 (fr) * 2010-10-01 2016-03-02 Intelligent Material Solutions Inc Particules monodispersées uniformes en morphologie et en taille et leur auto-assemblage dirigé par la forme
US10066163B2 (en) 2010-10-01 2018-09-04 Intelligent Material Solutions, Inc. Morphologically and size uniform monodisperse particles and their shape-directed self-assembly
CN102533272A (zh) * 2010-12-24 2012-07-04 中国科学院福建物质结构研究所 一步法合成水溶性的氨基化稀土掺杂氟化钇钠纳米颗粒
CN102533272B (zh) * 2010-12-24 2015-11-18 中国科学院福建物质结构研究所 一步法合成水溶性的氨基化稀土掺杂氟化钇钠纳米颗粒
CN103436263A (zh) * 2013-09-09 2013-12-11 天津师范大学 水溶性红绿光可调谐的稀土掺杂上转换纳米材料的制备方法
CN103980904A (zh) * 2014-03-27 2014-08-13 中国科学院福建物质结构研究所 一种氟化钇锂纳米复合材料及其制备方法和在光动力学治疗中的应用
CN103952138A (zh) * 2014-04-30 2014-07-30 深圳清华大学研究院 上转换复合材料及其制备方法、太阳能电池
WO2016016134A1 (fr) * 2014-07-28 2016-02-04 Koninklijke Philips N.V. Boîtes quantiques revêtues de silice à rendement quantique amélioré
TWI667332B (zh) * 2014-07-28 2019-08-01 荷蘭商皇家飛利浦有限公司 具有經改良量子效率之經二氧化矽塗覆之量子點
US10578257B2 (en) 2014-07-28 2020-03-03 Lumileds Llc Silica coated quantum dots with improved quantum efficiency
WO2017125951A1 (fr) * 2016-01-22 2017-07-27 Council Of Scientific And Industrial Research Microtiges de conversion ascendante à base de lanthane et leurs applications
US11078415B2 (en) 2016-01-22 2021-08-03 Council Of Scientific & Industrial Research Lanthanum based upconverting microrods and application thereof
CN105963697A (zh) * 2016-05-31 2016-09-28 陕西师范大学 基于荧光共轭聚合物与上转换纳米材料的复合抗菌剂及其使用方法
CN105963697B (zh) * 2016-05-31 2018-12-28 陕西师范大学 基于荧光共轭聚合物与上转换纳米材料的复合抗菌剂及其使用方法
CN107163944A (zh) * 2017-06-26 2017-09-15 大连理工大学 一种调控稀土上转换纳米材料形貌的共掺杂金属离子的制备方法
CN107163944B (zh) * 2017-06-26 2019-11-19 大连理工大学 一种调控稀土上转换纳米材料形貌的共掺杂金属离子的制备方法
CN112903733A (zh) * 2021-01-25 2021-06-04 中国科学院广州地球化学研究所 一种透射电镜能谱超分辨分析方法

Similar Documents

Publication Publication Date Title
WO2009046392A1 (fr) Synthèse de nanoluminophores à conversion ascendante dopés aux terres rares biofonctionnalisés
Chander Development of nanophosphors—A review
US20090121189A1 (en) Synthesis of bio-functionalized rare earth doped upconverting nanophosphors
Nuñez et al. Citrate mediated synthesis of uniform monazite LnPO4 (Ln= La, Ce) and Ln: LaPO4 (Ln= Eu, Ce, Ce+ Tb) spheres and their photoluminescence
US7303697B2 (en) Phosphor and production process for the same
Qiu et al. Tuning the size and shape of colloidal cerium oxide nanocrystals through lanthanide doping
US6869544B2 (en) Process for producing nanoscale yttrium aluminum garnet (YAG) fluorescent powders
US20060222757A1 (en) Method for making phosphors
Darbandi et al. Silica coated, water dispersible and photoluminescent Y (V, P) O4: Eu3+, Bi3+ nanophosphors
TW200813193A (en) Core/shell phosphor precursors and phosphors
JP6095726B2 (ja) サブミクロン希土類ホウ酸塩、その製造方法及び蛍光体としての使用
Su et al. Generation of tunable wavelength lights in core-shell CaWO 4 microspheres via co-doping with Na+ and Ln 3+(Ln= Tb, Sm, Dy, Eu)
KR101316955B1 (ko) 서브마이크론 바륨 및 마그네슘 알루미네이트, 그의 제조 방법 및 인광체로서의 용도
Ferhi et al. Hydrothermal synthesis and luminescence properties of nanospherical SiO2@ LaPO4: Eu3+ (5%) composite
Dembski et al. Luminescent silicate core–shell nanoparticles: Synthesis, functionalization, optical, and structural properties
Xu et al. Monodisperse and core-shell structured SiO2@ Lu2O3: Ln3+ (Ln= Eu, Tb, Dy, Sm, Er, Ho, and Tm) spherical particles: A facile synthesis and luminescent properties
Chang et al. Fabrication of novel luminor Y2O3: Eu3+@ SiO2@ YVO4: Eu3+ with core/shell heteronanostructure
Wawrzynczyk et al. Optimisation of ligand exchange towards stable water suspensions of crystalline NaYF4: Er3+, Yb3+ nanoluminophors
US8017036B1 (en) Single step gas phase flame synthesis method to produce sub-10 nanometer sized rare earth doped nanoparticles
US20160122640A1 (en) Silicon Precursors for Sunthesizing Multi-Elemental Inorganic Silicon-Containing Materials and Methods of Synthesizing Same
Tan et al. Monodisperse and core–shell structured NaYF4: Ln@ SiO2 (Ln= Yb/Er, Yb/Tm) microspheres: synthesis and characterization
CN115768853B (zh) 氮化物荧光体及其制造方法
CN118414405A (zh) 基于微射流反应器的纳米磷光体合成
Taghavinia et al. Europium-doped yttrium silicate nanoparticles embedded in a porous SiO2 matrix
JP2009138081A (ja) 微粒子分散溶液、当該微粒子分散溶液の製造方法、及びＬｎＯＸ−ＬｎＸ３複合体粒子の製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08835658

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 08835658

Country of ref document: EP

Kind code of ref document: A1