Dongmei Yang

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (62)361.7 Total impact

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    ABSTRACT: Oil-dispersible monodispersed NaCeF4, NaCeF4:Tb(3+) and NaCeF4:Yb(3+) nanoparticles were prepared through a thermal decomposition method. Phase purity, morphology and luminescence properties were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution TEM (HRTEM), and photoluminescence (PL) spectra, respectively. The starting amount of NaF is crucial for phase purity, and the reaction time had an effect on the morphology of the products. Products with rectangles, rods, and their mixtures could be obtained at different reaction times. Under UV excitation, energy transfer from Ce(3+) to lanthanide ions Tb(3+) and Yb(3+) could be observed in both NaCeF4:Tb(3+) and NaCeF4:Yb(3+). Energy transfer from Ce(3+) to Tb(3+) was proposed to be of a resonant type (ET) by luminescent dynamic studies with a theoretically calculated efficiency of up to 93%. Energy transfer from Ce(3+) to Yb(3+) was demonstrated to be a cooperative (CET) process, and the CET efficiency and total theoretical quantum efficiency were found to be 79% and 158%, respectively.
    Nanoscale 07/2014; 6(16). DOI:10.1039/c4nr02023e · 6.74 Impact Factor
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    ABSTRACT: Lanthanide ion (Ln(3+))-based upconversion nano/micromaterials that emit higher-energy visible light when excited by low-energy NIR light have aroused considerable attention in the forefront of materials science and biomedical fields, which stems from their unique optical and chemical properties including minimum photodamage to living organisms, low autofluorescence, high signal-to-noise ratio and detection sensitivity, and high penetration depth in biological or environmental samples. Thus, Ln(3+)-based upconversion materials are rising new stars and are quickly emerging as potential candidates to revolutionize novel biomedical applications. In this review article, we mainly focus on the recent progress in various chemical syntheses of Ln(3+)-based upconversion nanomaterials, with special emphasis on their application in stimuli-response controlled drug release and subsequent therapy. Functional groups that are introduced into the stimuli-responsive system can respond to external triggers, such as pH, temperature, light, and even magnetic fields, which can regulate the movement of the pharmaceutical cargo and release the drug at a desired time and in a desired area. This is crucial to boost drug efficacy in cancer treatment while minimizing the side effects of cytotoxic drugs. Many multifunctional (magnetic/upconversion luminescence and porous) composite materials based on Ln(3+) have been designed for controlled drug delivery and multimodal bioimaging. Finally, the challenges and future opportunities for Ln(3+)-based upconversion materials are discussed.
    Chemical Society Reviews 07/2014; 44(6). DOI:10.1039/c4cs00155a · 30.43 Impact Factor
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    ABSTRACT: We present the fabrication, upconversion‐luminescence cell imaging, and drug‐storage/release properties of upconversion‐luminescent core/mesoporous‐silica‐shell‐structured β‐NaYF4:Yb3+,Er3+@SiO2@mSiO2 composite nanospheres with a size of 80 nm. The biocompatibility test on L929 fibroblast cells using a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay reveals the low cytotoxicity of the system. The drug‐storage and in vitro release tests indicate that these multifunctional nanomaterials have controlled drug‐loading and ‐release properties for ibuprofen (IBU). Moreover, the upconversion (UC) emission intensity of IBU‐β‐NaYF4:Yb3+,Er3+@SiO2@mSiO2 composite nanospheres increases gradually along with the released amount of IBU. Additionally, upconversion luminescence images of β‐NaYF4:Yb3+,Er3+@SiO2@mSiO2 uptaken by cells show clear green emission under 980 nm infrared laser excitation. These findings make these material promising for applications in the bioimaging, drug delivery, and disease therapy fields on the basis of its upconversion‐luminescent and mesoporous properties. Biocompatibility in vitro, upconversion luminescence imaging, and capability of loading drug of multifunctional β‐NaYF4:Yb3+,Er3+@SiO2@mSiO2 nanospheres were investigated.
    European Journal of Inorganic Chemistry 04/2014; 2014(11). DOI:10.1002/ejic.201301460 · 2.97 Impact Factor
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    ABSTRACT: LaF3:Yb3+/Er3+ upconversion (UC) crystals with self-assembling microstructures have been synthesized via a simple one-pot ionothermal method. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy were used to characterize the samples. The samples crystallize in the pure hexagonal phase and self-assemble into the aligned arrays like a string of pearls. The effects of reaction temperature, reaction time, the volume ratio of ionic liquid (IL)/water in the mixed solvent and solvent composition on the size and morphology of the products have been studied in detail and a possible formation mechanism has also been proposed. The results indicate that the adoption of water-IL solvent mixture as reaction medium facilitates the particle morphology control. Furthermore, a bright yellowish-green emission can be obtained from the LaF3:Yb3+/Er3+ under 980 nm laser excitation. Such a material shows potential applications in color displays, light-emitting diodes, and optical storage.
    CrystEngComm 01/2014; 16(6):1056. DOI:10.1039/c3ce41854e · 3.86 Impact Factor
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    ABSTRACT: Incorporating the agents for magnetic resonance imaging (MRI), optical imaging and therapy in one nanostructured matrix to construct a multifunctional nanomedical platform has attracted great attention for simultaneous diagnostic and therapeutic applications. A facile methodology is reported on page 4150 by J. Lin and co-workers to construct a multifunctional nanocarrier composed of individual luminescent/magnetic β-NaYF4 :Yb(3+) , Er(3+) @β-NaGdF4 :Yb(3+) directly coated with mesoporous silica, followed by functionalization with poly(ethylene glycol), which can act as an effective platform for upconversion luminescence and magnetic resonance dual-modal imaging and in vivo anticancer drug delivery.
    Small 12/2013; 9(24):4149. DOI:10.1002/smll.201370154 · 7.51 Impact Factor
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    ABSTRACT: A new type of drug-delivery system (DDS) was constructed, in which the anti-cancer drug doxorubicin (DOX) was conjugated to the ultra-small sized (sub-10 nm) BaGdF5:Yb(3+)/Tm(3+) based upconversion nanoparticles (UCNPs). This multifunctional DDS simultaneously possesses drug delivery and optical/magnetic/X-ray computed tomography imaging capabilities. The DOX can be selectively released by cleavage of hydrazone bonds in acidic environment, which shows a pH-triggered drug release behavior. The MTT assay shows these DOX-conjugated UCNPs exhibit obvious cytotoxic effect on HeLa cells. Moreover, to improve the upconversion luminescence intensity, core-shell structured UCNPs were constructed. The in vitro upconversion luminescence images of these UCNPs uptaken by HeLa cells show bright emission with high contrast. In addition, these UCNPs were further explored for T1-weighted magnetic resonance (MR) and X-ray computed tomography (CT) imaging in vitro. Long-term in vivo toxicity studies indicated that mice intravenously injected with 10 mg/kg of UCNPs survived for 40 days without any apparent adverse effects to their health. The results indicate that this multifunctional drug-delivery system with optimized size, excellent optical/MR/CT trimodal imaging capabilities, and pH-triggered drug release property is expected to be a promising platform for simultaneous cancer therapy and bioimaging.
    Biomaterials 12/2013; DOI:10.1016/j.biomaterials.2013.11.018 · 8.31 Impact Factor
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    ABSTRACT: Controlling the anti-cancer drugs activity and release on demand is very significant in cancer therapy. The photo-activated platinum (IV) pro-drug is stable in dark and can be activated by the UV light. In this study, we develop a multifunctional drug delivery system combining upconversion luminescence (UCL) /magnetic resonance (MR)/computer tomography (CT) tri-modality imaging and NIR-activated platinum pro-drug delivery together. We use the core-shell structured upconversion nanoparticles to convert the absorbed NIR light into UV to activate trans-platinum (IV) pro-drug, trans, trans, trans-[Pt(N3)2(NH3)(py)(O2CCH2CH2COOH)2] (DPP). Compared with using the UV directly, the NIR has a higher tissue penetration depth and is less harmful to the health. Meanwhile, the upconversion nanoparticles can effectively deliver the platinum (IV) pro-drugs into the cells by endocytosis. The mice treated with pro-drug conjugated nanoparticles under near infrared (NIR) irradiation demonstrated better inhibition of tumor growth than that under direct UV irradiation. This multifunctional nanocomposite could be used as multi-modality bioimaging contrast agents and transducers by converting NIR light into UV for control of drugs activity in practical cancer therapy.
    Journal of the American Chemical Society 11/2013; 135(50). DOI:10.1021/ja410028q · 11.44 Impact Factor
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    ABSTRACT: Water-soluble Ln3+-doped β-NaGdF4 (Ln = Ce, Tb, Eu, Dy) nanocrystals were synthesized via a hydrothermal method followed by phase transferring. The nanocrystals crystallize in the hexagonal phase as β-NaGdF4. Tunable multicolor down-conversion emissions can be achieved from Ln3+-doped β-NaGdF4 nanocrystals under a single ultraviolet excitation. During the down-conversion emission, energy transfer process like Ce3+ → Gd3+ → (Gd3+)n → Ln3+ occurred, in which Gd3+ ions play an important intermediate role. The magnetic properties of the obtained nanocrystals were investigated in detail. The nanocrystals display paramagnetic and superparamagnetic properties with mass magnetic susceptibility values of 6.77 × 10−5 emu/g · Oe and 1.92 × 10−3 emu/g · Oe at 300 K and 2 K, respectively. The T1-weighted magnetic resonance image that measured in aqueous solutions with different Gd3+ concentrations reveals the contrast brightening increases with the concentration of Gd3+ ions. Such magnetic/luminescent dual-function material may have promising applications in multiple biolabels and magnetic resonance imaging.
    Materials Research Bulletin 08/2013; 48(8):2843–2849. DOI:10.1016/j.materresbull.2013.04.014 · 1.97 Impact Factor
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    ABSTRACT: Multifunctional nanocomposites integrating mesoporous and luminescence properties into a single entity are synthesized via a facile and effective approach. Oleic acid capped β-NaYF4:Ce(3+)/Tb(3+) nanoparticles (NPs) are transferred into aqueous solution by cetyltrimethylammonium bromide (CTAB) surfactants, and further encapsulated with uniform mesoporous silica shell followed by the surface modification with poly(ethylene glycol) (PEG), leading to the formation of water-dispersible and biocompatible core-shell structured β-NaYF4:Ce(3+)/Tb(3+)@mSiO2-PEG (denoted as NPs@mSiO2-PEG) nanospheres. The as-synthesized nanospheres show a typical mesoporous structure and a green emission under UV irradiation. Doxorubicin hydrochloride (DOX), a widely used anti-cancer drug, is used as a model drug to evaluate the loading and controlled release behaviors of the NPs@mSiO2-PEG in phosphoric acidic buffer solutions (PBS) at different pH values (pH = 7.4 and 5.0). The composite carriers provide a pH-sensitive drug release pattern and the drug releases faster under lower pH value. The endocytosis process of fluorescein isothiocyanate (FITC)-labelled nanospheres is characterized using flow cytometry and confocal laser scanning microscopy (CLSM) against A549 cells. The in vitro cytotoxic effect against A549 cells of the DOX-loaded carriers is investigated in detail. In addition, the extent of drug release can be monitored by the variation of photoluminescence (PL) intensity of β-NaYF4:Ce(3+)/Tb(3+). Considering the good biocompatibility and pH-dependent drug release pattern, such core-shell structured luminescent NPs@mSiO2-PEG nanospheres have potential applications in controlled drug delivery.
    Dalton Transactions 05/2013; 42(27). DOI:10.1039/c3dt50658d · 4.10 Impact Factor
  • Advanced Healthcare Materials 04/2013; 2(4). DOI:10.1002/adhm.201370019 · 4.88 Impact Factor
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    ABSTRACT: A folic acid targeted anticancer drug delivery system based on Pt (IV) complexes pro-drug conjugated up- conversion NaYF(4) :Yb(3+) /Er(3+) nanoparticles has been developed. The platinum (IV) complexes as pro-drugs can exhibit anti-cancer activities when the platinum (IV) complexes are reduced to platinum (II) in the intracellular environment. Meanwhile, the drug delivery system can be used as a luminescent probe for up-conversion cell imaging.
    04/2013; 2(4). DOI:10.1002/adhm.201200234
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    ABSTRACT: Pure Ca2Ba3(PO4)3Cl and rare earth ion (Eu2+/Ce3+/Dy3+/Tb3+) doped Ca2Ba3(PO4)3Cl phosphors with the apatite structure have been prepared via a Pechini-type sol-gel process. X-ray diffraction (XRD) and structure refinement, photoluminescence (PL) spectra, cathodoluminescence (CL) spectra, absolute quantum yield, as well as lifetimes were utilized to characterize samples. Under UV light excitation, the undoped Ca2Ba3(PO4)3Cl sample shows broad band photoluminescence centered near 480 nm after being reduced due to the defect structure. Eu2+ and Ce3+ ion doped Ca2Ba3(PO4)3Cl samples also show broad 5d → 4f transitions with cyan and blue colors and higher quantum yields (72% for Ca2Ba3(PO4)3Cl:0.04Eu2+; 67% for Ca2Ba3(PO4)3Cl:0.016Ce3+). For Dy3+ and Tb3+ doped Ca2Ba3(PO4)3Cl samples, they give strong line emissions coming from 4f → 4f transitions. Moreover, the Ce3+ ion can transfer its energy to the Tb3+ ion in the Ca2Ba3(PO4)3Cl host, and the energy transfer mechanism has been demonstrated to be a resonant type, via a dipole-quadrupole interaction. However, under the low voltage electron beam excitation, Tb3+ ion doped Ca2Ba3(PO4)3Cl samples present different luminescence properties compared with their PL spectra, which is ascribed to the different excitation mechanism. On the basis of the good PL and CL properties of the Ca2Ba3(PO4)3Cl:A (A = Ce3+/Eu2+/Tb3+/Dy3+), Ca2Ba3(PO4)3Cl might be promising for application in solid state lighting and field-emission displays.
    Inorganic Chemistry 03/2013; 52(6). DOI:10.1021/ic3025759 · 4.79 Impact Factor
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    ABSTRACT: Small (2-28 nm) NaREF(4) (rare earth (RE)=Nd-Lu, Y) nanoparticles (NPs) were prepared by an oil/water two-phase approach. Meanwhile, hydrophilic NPs can be obtained through a successful phase-transition process by introducing the amphiphilic surfactant sodium dodecylsulfate (SDS) into the same reaction system. Hollow-structured NaREF(4) (RE=Y, Yb, Lu) NPs can be fabricated in situ by electron-beam lithography on solid NPs. The MTT assay indicates that these hydrophilic NPs with hollow structures exhibit good biocompatibility. The as-prepared hollow-structured NPs can be used as anti-cancer drug carriers for drug storage/release investigations. Doxorubicin hydrochloride (DOX) was taken as model drug. The release of DOX from hollow α-NaLuF(4) :20 % Yb(3+) , 2 % Er(3+) exhibits a pH-sensitive release patterns. Confocal microscopy observations indicate that the NPs can be taken up by HeLa cells and show obvious anti-cancer efficacy. Furthermore, α-NaLuF(4) :20 % Yb(3+) , 2 % Er(3+) NPs show bright-red emission under IR excitation, making both the excitation and emission light fall within the "optical window" of biological tissues. The application of α-NaLuF(4) :20 % Yb(3+) , 2 % Er(3+) in the luminescence imaging of cells was also investigated, which shows a bright-red emission without background noise.
    Chemistry - A European Journal 02/2013; 19(8). DOI:10.1002/chem.201203634 · 5.70 Impact Factor
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    ABSTRACT: Hollow and porous structured GdVO4:Dy3+ spheres were fabricated via a facile self-sacrificing templated method. The large cavity allows them to be used as potential hosts for therapeutic drugs, and the porous feature of the shell allows guest molecules to easily pass through the void space and surrounding environment. The samples show strong yellow-green emission of Dy3+ (485 nm, 4F9/2→6H15/2; 575 nm, 4F9/2→6H13/2) under UV excitation. The emission intensity of GdVO4:Dy3+ was weakened after encapsulation of anti-cancer drug (doxorubicin hydrochloride, DOX) and gradually restored with the cumulative released time of DOX. These hollow spheres were nontoxic to HeLa cells, while DOX-loaded samples led to apparent cytotoxicity as a result of the sustained release of DOX. ICP measurement indicates that free toxic Gd ions can hardly dissolate from the matrix. The endocytosis process of DOX-loaded hollow spheres is observed using confocal laser scanning microscopy (CLSM). Furthermore, GdVO4:Dy3+ hollow spheres can be used for T1-weighted magnetic resonance (MR) imaging. These results implicate that the luminescent GdVO4:Dy3+ spheres with hollow and porous structure are promising platforms for drug storage/release and MR imaging.
    Langmuir 01/2013; 29(4). DOI:10.1021/la304551y · 4.38 Impact Factor
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    ABSTRACT: Upconversion luminescent β-NaYF4:Yb3+, Er3+ nanoparticles (UCNPs) were encapsulated with uniform mesoporous silica shells, which were further modified with poly(ethylene glycol) (PEG) and cancer-targeting ligand folic acid (FA), resulting in the formation of water-dispersible and biologically functionalized core–shell structured UCNPs@mSiO2 nanoparticles with an overall average size of around 80 nm. The obtained multifunctional nanocomposite spheres can be performed as an anti-cancer drug delivery carrier and applied for cell imaging. It is found that anti-cancer drug doxorubicin hydrochloride (DOX) can be absorbed into UCNPs@mSiO2-PEG/FA nanospheres and released in a pH-sensitive pattern. In vitro cell cytotoxicity tests on cancer cells verified that DOX-loaded UCNPs@mSiO2-PEG/FA nanospheres exhibited greater cytotoxicity with respect to free DOX and DOX-loaded UCNPs@mSiO2-PEG at the same concentrations, owing to the increase of cell uptake of anti-cancer drug delivery vehicles mediated by the FA receptor. Moreover, the upconversion luminescence image of UCNPs@mSiO2-PEG/FA taken up by cells shows green emission under 980 nm infrared laser excitation, making the UCNPs@mSiO2-PEG/FA nanocomposite spheres promising candidates as bioimaging agents. These findings highlight the promise of the highly versatile multifunctional nanoparticles for simultaneous imaging and therapeutic applications.
    01/2013; 1(2):213-223. DOI:10.1039/C2BM00087C
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    ABSTRACT: Uniform α-NaYF(4:)Yb(3+), Er(3+) nanospheres (∼130 nm) with mesoporous shell and hollow interior structure were synthesized by using Y(OH)CO(3):Yb(3+), Er(3+) nanospheres (NPs) as sacrificial templates via a surface-protected "etching" and hydrothermal ion-exchange process. In this process, polyethylenimine (PEI) ligands played a key role in formation of the hollow structured α-NaYF(4) nanospheres, i.e., they can effectively protect the surface of the Y(OH)CO(3) from rapid dissolution by H(+). Moreover, folic acid (FA), a commonly used cancer-targeting agent was conjugated on the surface of NPs based on the presence of free amine groups. The as-prepared FA-modified hollow NPs can be performed as anti-cancer drug carriers for the investigation of drug storage/release properties, which exhibit greater cytotoxicity than DOX-loaded α-NaYF(4) NPs due to the specific cell uptake by HeLa cells via FA receptor-mediate endocytosis. Furthermore, upconversion (UC) luminescence images of FA-modified α-NaYF(4):Yb(3+), Er(3+) NPs uptaken by cells shows bright green emission without background noise under 980 nm infrared laser excitation. Thus, these multifunctional nanospheres combining UC luminescent property and hollow and mesoporous structure have potential for simultaneous targeted anti-cancer drug delivery and cell imaging.
    Biomaterials 11/2012; 34(5). DOI:10.1016/j.biomaterials.2012.11.004 · 8.31 Impact Factor
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    ABSTRACT: In this study, multifunctional poly(acrylic acid) modified lanthanide-doped GdVO(4) nanocomposites [PAA@GdVO(4): Ln(3+) (Ln = Yb/Er, Yb/Ho, Yb/Tm)] were constructed by filling PAA hydrogel into GdVO(4) hollow spheres via photoinduced polymerization. The up-conversion (UC) emission colors (green, red and blue) can be tuned by changing the codopant compositions in the matrices. The composites have potential applications as bio-probes for cell imaging. Meanwhile, the hybrid spheres can act as T(1) contrast agents for magnetic resonance imaging (MRI) owing to the existence of Gd(3+) ions on the surface of composites. Due to the nature of PAA, DOX-loaded PAA@GdVO(4):Yb(3+)/Er(3+) system exhibits pH-dependent drug releasing kinetics. A lower pH offers a faster drug release rate. Such character makes the loaded DOX easily released at cancer cells. The cell uptake process of drug-loaded composites was observed by using confocal laser scanning microscopy (CLSM). The results indicate the potential application of the multifunctional composites as theragnostics (effective bimodal imaging probes and pH-responsive drug carriers).
    Nanoscale 11/2012; 5(1). DOI:10.1039/c2nr33130f · 6.74 Impact Factor
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    ABSTRACT: Photoluminescence (PL) and cathodoluminescence (CL) properties of Ln3+ (Ln = Tb, Dy, Eu, Tm, Ce) and Mn2+-activated KCaGd(PO4)2 (KCG) phosphors were investigated. Under UV excitation, KCG:Tb3+, KCG:Dy3+, KCG:Eu3+, KCG:Tm3+, and KCG:Mn2+ samples exhibit the characteristic emission of the activators, respectively. By altering doping activators and adjusting their relative doping concentrations in the KCG host, we obtained white emission in KCG:Tm3+, Tb3+, Eu3+, KCG:Tb3+, Mn2+, Eu3+, KCG:Tb3+, Eu3+, and KCG:Dy3+, Eu3+ samples under the excitation of 275 or 356 nm UV. Besides, there exist three energy transfer pairs in the KCG host, i.e., Ce3+ → Tb3+, Ce3+ → Dy3+, and Ce3+ → Mn2+. Upon excitation at 280 nm, the absolute quantum yield of the optimized KCG:Ce3+, Tb3+ is 90.6%. Under the low-voltage electron beam excitation, the CL properties of KCG:Ln3+/Mn2+ phosphors have been investigated in detail, and a variety of colors can be obtained in these samples. All of the results of this study reveal that the as-prepared KCG:Ln3+/Mn2+ phosphors have good luminescent intensity under UV and the low-voltage electron beam excitation, especially KCG:Ce3+, Tb3+ samples, making these materials have potential applications in white-light LEDs and field emission display devices.
    Journal of Materials Chemistry 10/2012; 22(45):23789-23798. DOI:10.1039/C2JM34991D · 6.63 Impact Factor
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    ABSTRACT: Ce(3+), Tb(3+) and Mn(2+)-activated KSrGd(PO(4))(2) phosphors with high absolute quantum efficiencies were first prepared by a Pechini-type sol-gel method. The photoluminescence and cathodoluminescence intensities of Tb(3+)/Mn(2+) can be enhanced by co-doped Ce(3+) ions into the KSrGd(PO(4))(2) host via the energy transfer process.
    Dalton Transactions 10/2012; 41(46). DOI:10.1039/c2dt31957h · 4.10 Impact Factor
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    ABSTRACT: A series of LaOF:Ln(3+) (Ln = Eu, Tb, Sm, Dy, Tm, and/or Ho) nanocrystals with good dispersion have been successfully prepared by the hydrothermal method followed a heat-treatment process. Under ultraviolet radiation and low-voltage electron beam excitation, the LaOF:Ln(3+) nanocrystals show the characteristic f-f emissions of Ln(3+) (Ln = Eu, Tb, Sm, Dy, Tm, or Ho) and give red, blue-green, orange, yellow, blue, and green emission, respectively. Moreover, there exists simultaneous luminescence of Tb(3+), Eu(3+), Sm(3+), Dy(3+), Tm(3+), or Ho(3+) individually when codoping them in the single-phase LaOF host (for example, LaOF:Tb(3+), Eu(3+)/Sm(3+); LaOF:Tm(3+), Dy(3+)/Ho(3+); LaOF:Tm(3+), Ho(3+), Eu(3+) systems), which is beneficial to tune the emission colors. Under low-voltage electron beam excitation, a variety of colors can be efficiently adjusted by varying the doping ions and the doping concentration, making these materials have potential applications in field-emission display devices. More importantly, the energy transfer from Tm(3+) to Ho(3+) in the LaOF:Tm(3+), Ho(3+) samples under UV excitation was first investigated and has been demonstrated to be a resonant type via a quadrupole-quadrupole mechanism. The critical distance (R(Tm-Ho)) is calculated to be 28.4 Å. In addition, the LaOF:Tb(3+) and LaOF:Tm(3+) phosphors exhibit green and blue luminescence with better chromaticity coordinates, color purity, and higher intensity compared with the commercial green phosphor ZnO:Zn and blue phosphor Y(2)SiO(5):Ce(3+) to some extent under low-voltage electron beam excitation.
    Inorganic Chemistry 09/2012; 51(20):11106-16. DOI:10.1021/ic301662c · 4.79 Impact Factor