Study on the Film-Forming Mechanism of Polymer-Metal Oxide Composite Ink Systems Containing Different Polymer Molecules.

A printable, flexible display panel is an important trend in the field of information display, which requires better mechanical and electrical properties of device materials. Polymer-metal oxide composite materials are promising in the functional layer of a thin-film transistor (TFT) and can be sufficiently fabricated by polymer-metal salt solution systems through the sol-gel process. For the development of polymer-metal oxide composite ink, it is necessary to study the film-forming mechanism of the composite film during solidification, which is an important reference in ink component design. However, the evolution of the composite structure is quite complex, which brings a challenge to characterization and analyzation. We applied a series of characterization methods to study the film-forming process of composite ink from sol to gel and to solid, and an emerging testing technology, nano-infrared spectroscopy (nano-IR), was applied to characterize the gel film. The research conclusion showed that the type of functional group can significantly affect the morphology of the initial particle and can finally determine the microstructure of the composite film. The study provides references for the development of composite ink as well as the characterization method for ink and film with complex composition.

Energy Transfer from Ce3+ to Tb3+ /Dy3+ /Mn2+ in Ca9 Ga(PO4 )7 Phosphors: Synthesis, Structure and Tunable Multicolor Luminescent Properties.

A series of Ca9 Ga(PO4 )7 :Ce3+ /Tb3+ /Dy3+ /Mn2+ phosphors with tunable color, in which Ce3+ acts as the sensitizer, was synthesized. Energy transfer (ET) from Ce3+ to Tb3+ /Dy3+ /Mn2+ was investigated in detail. Tb3+ /Dy3+ /Mn2+ single-doped Ca9 Ga(PO4 )7 can exhibit green, yellow, and red emission, respectively. Incorporating Ce3+ into a Tb3+ /Dy3+ /Mn2+ single-doped Ca9 Ga(PO4 )7 phosphor can remarkably promote the luminous efficiency of the Tb3+ /Dy3+ /Mn2+ ions. This enhancement originates from an efficient ET from Ce3+ to Tb3+ /Dy3+ /Mn2+ . The ET was validated by luminescence spectra, decay dynamics, and schematic energy levels. Moreover, the intensity ratio of red emission of Mn2+ to violet emission of Ce3+ was analyzed based on energy-transfer and lifetime measurements. In Ce3+ -Tb3+ , Ce3+ -Dy3+ , and Ce3+ -Mn2+ doped Ca9 Ga(PO4 )7 , the emitting color changed from violet to green, yellow, and red, respectively, which indicates the potential use of this new tunable phosphor in UV light-emitting diodes.

Fluorometric aptamer based assay for ochratoxin A based on the use of exonuclease III.

This study describes an aptamer based assay for the mycotoxin ochratoxin A (OTA). The method is based on the use of an OTA-specific aptamer, exonuclease (Exo) III, SYBR Gold as a fluorescent probe, and a complementary strand that specifically combines with the aptamer. In the presence of OTA, the aptamer and OTA hybridize, thereby resulting in the formation of ssDNA, which is not digested by Exo III. Intense fluorescence is observed after addition of SYBR Gold (best measured at excitation/emission wavelengths of 495/540 nm). Fluorescence increases linearly with the log of the OTA concentration in the range from 8 to 1000 ng·mL-1. The detection limit is 4.7 ng·mL-1. The assay was applied to the determination of OTA in diluted [2%(v/v)] red wine, and recoveries and RSDs ranged between 93.5% and 113.8%, and between 3.2% and 5.7%, respectively. Graphical abstract In the presence of ochratoxin A (OTA), specific combinations of aptamer and OTA may occur and result in DNA double strands being untied, which avoids being digested by Exo III. Intense fluorescence is observed after SYBR Gold addition.

Gram-Scale Synthesis of Hydrophilic PEI-Coated AgInS2 Quantum Dots and Its Application in Hydrogen Peroxide/Glucose Detection and Cell Imaging.

Assisted with polyethylenimine, 4.0 L of water-soluble AgInS2 quantum dots (AIS QDs) were successfully synthesized in an electric pressure cooker. As-prepared QDs exhibit yellow emission with a photoluminescence (PL) quantum yield up to 32%. The QDs also show excellent water/buffer stability. The highly luminescent AIS QDs are used to explore their dual-functional behavior: detection of hydrogen peroxide (H2O2)/glucose and cell imaging. The amino-functionalized AIS QDs show high sensitivity and specificity for H2O2 and glucose with detection limits of 0.42 and 0.90 µM, respectively. A linear correlation was established between PL intensity and concentration of H2O2 in the ranges of 0.5-10 µM and 10-300 µM, while the linear ranges were 1-10 µM and 10-1000 µM for detection of glucose. The AIS QDs reveal negligible cytotoxicity on HeLa cells. Furthermore, the luminescence of AIS QDs gives the function of optical imaging.

Homogeneous Synthesis and Electroluminescence Device of Highly Luminescent CsPbBr3 Perovskite Nanocrystals.

Highly luminescent CsPbBr3 perovskite nanocrystals (PNCs) are homogeneously synthesized by mixing toluene solutions of PbBr2 and cesium oleate at room temperature in open air. We found that PbBr2 can be easily dissolved in nonpolar toluene in the presence of tetraoctylammonium bromide, which allows us to homogeneously prepare CsPbBr3 perovskite quantum dots and prevents the use of harmful polar organic solvents, such as N,N-dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. Additionally, this method can be extended to synthesize highly luminescent CH3NH3PbBr3 perovskite quantum dots. An electroluminescence device with a maximal luminance of 110 cd/m2 has been fabricated by using high-quality CsPbBr3 PNCs as the emitting layer.

Fluorometric aptamer assay for ochratoxin A based on the use of single walled carbon nanohorns and exonuclease III-aided amplification.

The authors describe an aptamer based assay for the food mycotoxin ochratoxin A (OTA). It is based on the use of exonuclease III (Exo III) which assists in signal amplification, and of single-walled carbon nanohorns (SWCNHs) which act as quenchers of fluorescence. The detection scheme employs a hairpin probe (HP) and a signal probe (SP) labeled with carboxyfluorescein (FAM) at its 5'-end. The fluorescence of intact SPs (best measured at excitation/emission wavelengths of 495/518 nm) is quenched by SWCNHs. The HP contains the OTA-specific aptamer sequence and is partially complementary to the SP. After addition of OTA, the aptamer binds OTA and thus exposes a single-stranded sequence that can hybridize with the SP. Exo III digests the SP to liberate the free fluorophore labels. The damaged SPs no longer are adsorbed by the SWCNHs so that fluorescence is no longer quenched. The method has a detection range that is linear from 10 nM to 1000 nM (with a correlation coefficient of 0.997). The limit of detection (LOD), calculated on the basis of a signal to noise ratio of 3, is 4.2 nM. The procedure was validated by the quantitation of OTA in spiked real samples and were found to be free of interference by the sample matrix. Recoveries ranged from 93.8 to 113.0% in beer and from 92.0 to115.9% in red wine. Graphical abstract After adding ochratoxin A (OTA), the aptamer region in hairpin probe (HP) combined with OTA and thus exposed a single-stranded sequence to hybridize with signal probe (SP). Exonuclease III (Exo III) digested SP to liberate the free fluorophore (FAM).

High color rendering index warm white light emitting diodes fabricated from AgInS2/ZnS quantum dot/PVA flexible hybrid films.

Flexible luminescent materials, with the advantages of foldability and crack resistance, have attracted extensive interest owing to their broad application in collapsible optoelectronic devices. In this work, highly luminescent water-soluble green and red AgInS2/ZnS core/shell quantum dots (QDs) are synthesized in an electric pressure cooker. Luminescent and flexible films are fabricated by combining QDs with polyvinyl alcohol (PVA), and the green and red QD/PVA films show a high photoluminescence quantum yield (PLQY) of about 55% and 64% upon 460 nm excitation, respectively. Finally, the green and red QD/PVA films are successfully applied on top of a conventional blue InGaN chip for remote-type warm-white LEDs. As-fabricated warm-white LEDs exhibit a higher color rendering index (CRI) of about 90.2 and a correlated color temperature (CCT) of 3698 K.

Morphology control and multicolor up-conversion luminescence of GdOF:Yb3+/Er3+, Tm3+, Ho3+ nano/submicrocrystals.

In this paper, well defined GdOF:Yb(3+)/Er(3+), Tm(3+), Ho(3+) nano/submicrocrystals with multiform morphologies were prepared via the urea-based precipitation method without using any surfactants. The morphologies of the GdOF products, including spindles and spheres with different sizes (30-550 nm), could be easily modulated by changing the fluorine sources, and the possible formation mechanism has been presented. XRD, FT-IR, SEM, TEM, as well as up-conversion (UC) photoluminescence spectra were used to characterize the prepared samples. Under 980 nm NIR excitation, the relative emission intensities and emission colors of Yb(3+)/Er(3+), Yb(3+)/Tm(3+) and Yb(3+)/Ho(3+) doped GdOF could be precisely adjusted over a wide range by tuning the Yb(3+) doping concentration. The strategies for color tuning of UC emission proposed in the current system may be helpful to achieve efficient multicolor luminescence under 980 nm laser excitation. In addition, the corresponding UC mechanisms in the co-doping GdOF systems were analyzed in detail based on the emission spectra and the plot of luminescence intensity to pump power.

Realize short-wave infrared luminescence in NaScP2O7:Cr3+,Yb3+ phosphor: Spectral and energy transfer.

Short-wave infrared emitting phosphors have extensive applications for spectroscopy technology. The near-infrared phosphor NaScP2O7:Cr3+ that we present in this work has a full width at half maximum (FWHM) of approximately 196 nm, which ranges from 700 to 1200 nm. To achieve efficient short-wave infrared, Yb3+ ions were co-doped. The NaScP2O7:Cr3+,Yb3+ material emitted infrared bands with peaks at 970 and 1003 nm upon excitation at450 nm. Benefitting from energy transfer (ET), the light in the 900-1200 nm from Yb3+ is effectively enhanced. Photoluminescence spectra, thermal quenching, and decay curves of Cr3+/Yb3+ single and codoped NaScP2O7 were investigated. An internal quantum yield of 29.6 % wasdemonstrated by the optimized phosphor NaScP2O7:Cr3+,Yb3+. Furthermore, The final fabrication of the short-wave infrared pc-LED was done through the combination of a blue-emitting chip and NaScP2O7:Cr3+,Yb3+ phosphor, thereby showing great promise for real implementations.

One-step synthesis of small-sized and water-soluble NaREF4 upconversion nanoparticles for in vitro cell imaging and drug delivery.

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.

Electrospun upconversion composite fibers as dual drugs delivery system with individual release properties.

Novel multifunctional poly(ε-caprolactone)-gelatin encapsulating upconversion core/shell silica nanoparticles (NPs) composite fibers as dual drugs delivery system (DDDS), with indomethacin (IMC) and doxorubicin (DOX) releasing in individual release properties, have been designed and fabricated via electrospinning process. Uniform and monodisperse upconversion (UC) luminescent NaYF4:Yb(3+), Er(3+) nanocrystals (UCNCs) were encapsulated with mesoporous silica shells, resulting in the formation of core/shell structured NaYF4:Yb(3+), Er(3+)@mSiO2 (UCNCs@mSiO2) NPs, which can be performed as DOX delivery carriers. These UCNCs@mSiO2 NPs loading DOX then were dispersed into the mixture of poly(ε-caprolactone) (PCL) and gelatin-based electrospinning solution containing IMC, followed by the preparation of dual drug-loaded composite fibers (DDDS) via electrospinning method. The drugs release profiles of the DDDS were measured, and the results indicated that the IMC and DOX released from the electrospun composite fibers showed distinct properties. The IMC in the composite fibers presented a fast release manner, while DOX showed a sustained release behavior. Moreover, the UC luminescent intensity ratios of (2)H(11/2)/(4)S(3/2)-(4)I(15/2) to (4)F(9/2)-(4)I(15/2) from Er(3+) vary with the amounts of DOX in the system, and thus drug release can be tracked and monitored by the luminescence resonance energy transfer (LRET) mechanism.

Multiwalled carbon nanotubes and NaYF4:Yb3+/Er3+ nanoparticle-doped bilayer hydrogel for concurrent NIR-triggered drug release and up-conversion luminescence tagging.

Bilayer thermosensitive P(NIPAm-co-AAm) hydrogel discs were prepared by a facile UV light initiation process from N-isopropylacrylamide (NIPAm) and acrylamide (AAm) monomers' cross-linking copolymerization. Poly(ethylene glycol) (PEG) as a pore-forming agent was added in order to form a porous structure and improve the water content in the hydrogel. Functional materials of NaYF4:Yb(3+)/Er(3+) nanoparticles and multiwalled carbon nanotubes (MWCNTs) were incorporated into different layers of the P(NIPAm-co-AAm) hydrogel for the purpose of up-conversion luminescence labeling and the NIR light antenna effect, respectively. Significantly improved drug release from composite hydrogels was achieved in response to 980 nm NIR light irradiation by using lysozyme as a macromolecular drug. The multifunctional hydrogel reported here provides a platform for simultaneous NIR luminescence labeling and NIR-driven drug release.

Fabrication of hollow and porous structured GdVO4:Dy3+ nanospheres as anticancer drug carrier and MRI contrast agent.

Hollow and porous structured GdVO(4):Dy(3+) 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 Dy(3+) (485 nm, (4)F(9/2) → (6)H(15/2); 575 nm, (4)F(9/2) → (6)H(13/2)) under UV excitation. The emission intensity of GdVO(4):Dy(3+) was weakened after encapsulation of anticancer 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, GdVO(4):Dy(3+) hollow spheres can be used for T(1)-weighted magnetic resonance (MR) imaging. These results implicate that the luminescent GdVO(4):Dy(3+) spheres with hollow and porous structure are promising platforms for drug storage/release and MR imaging.

Luminescence and energy transfer properties of Ca2Ba3(PO4)3Cl and Ca2Ba3(PO4)3Cl:A (A = Eu2+/Ce3+/Dy3+/Tb3+) under UV and low-voltage electron beam excitation.

Pure Ca2Ba3(PO4)3Cl and rare earth ion (Eu(2+)/Ce(3+)/Dy(3+)/Tb(3+)) 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. Eu(2+) and Ce(3+) 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:0.04Eu(2+); 67% for Ca2Ba3(PO4)3Cl:0.016Ce(3+)). For Dy(3+) and Tb(3+) doped Ca2Ba3(PO4)3Cl samples, they give strong line emissions coming from 4f → 4f transitions. Moreover, the Ce(3+) ion can transfer its energy to the Tb(3+) 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, Tb(3+) 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 = Ce(3+)/Eu(2+)/Tb(3+)/Dy(3+)), Ca2Ba3(PO4)3Cl might be promising for application in solid state lighting and field-emission displays.

Rapid, large-scale, morphology-controllable synthesis of YOF:Ln3+ (Ln = Tb, Eu, Tm, Dy, Ho, Sm) nano-/microstructures with multicolor-tunable emission properties.

YOF:Ln(3+) (Ln = Tb, Eu, Tm, Dy, Ho, Sm) nano-/microstructures with a variety of novel and well-defined morphologies, including nanospheres, nanorod bundles, and microspindles, have been prepared through a convenient modified urea-based homogeneous precipitation (UBHP) technique followed by a heat treatment. The sizes and morphologies of the YOF products could be easily modulated by changing the pH values and fluoride sources. XRD, TG-DTA, FT-IR, SEM, and TEM, as well as photoluminescence (PL) and cathodoluminescence (CL) spectra, were used to characterize the prepared samples. The YOF:Ln(3+) nanospheres show the characteristic f-f transitions of Ln(3+) (Ln = Tb, Eu, Tm, Dy, Ho, Sm) ions and give bright green, red, blue, yellow, blue-green, and yellow-orange emission, respectively, under UV light and low-voltage electron beam excitation. Furthermore, YOF:0.03Tb(3+) phosphors exhibit green luminescence with superior properties in comparison with the commercial phosphor ZnO:Zn to a degree, which is advantageous for improving display quality. Because of the simultaneous luminescence of Ln(3+) in the YOF host, the luminescence colors of YOF:Ln(3+) phosphors can be precisely adjusted by changing the doped Ln(3+) ions and corresponding concentrations, which makes these materials hold great promise for applications in field-emission displays.

Poly(acrylic acid)-modified Fe3O4 microspheres for magnetic-targeted and pH-triggered anticancer drug delivery.

Monodisperse poly(acrylic acid)-modified Fe(3)O(4) (PAA@Fe(3)O(4)) hybrid microspheres with dual responses (magnetic field and pH) were successfully fabricated. The PAA polymer was encapsulated into the inner cavity of Fe(3)O(4) hollow spheres by a vacuum-casting route and photo-initiated polymerization. TEM images show that the samples consist of monodisperse porous spheres with a diameter around 200 nm. The Fe(3)O(4) spheres, after modification with the PAA polymer, still possess enough space to hold guest molecules. We selected doxorubicin (DOX) as a model drug to investigate the drug loading and release behavior of as-prepared composites. The release of DOX molecules was strongly dependent on the pH value due to the unique property of PAA. The HeLa cell-uptake process of DOX-loaded PAA@Fe(3)O(4) was observed by confocal laser scanning microscopy (CLSM). After being incubated with HeLa cells under magnet magnetically guided conditions, the cytotoxtic effects of DOX-loaded PAA@Fe(3)O(4) increased. These results indicate that pH-responsive magnetic PAA@Fe(3)O(4) spheres have the potential to be used as anticancer drug carriers.

Hydrothermal derived LaOF:Ln3+ (Ln = Eu, Tb, Sm, Dy, Tm, and/or Ho) nanocrystals with multicolor-tunable emission properties.

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.

Ln(3+) (Ln = Eu, Dy, Sm, and Er) ion-doped YVO(4) nano/microcrystals with multiform morphologies: hydrothermal synthesis, growing mechanism, and luminescent properties.

YVO(4) nano/microcrystals with multiform morphologies, such as nanoparticles, microdoughnut, micropancake, pillar structure, and microflower, have been synthesized via a facile hydrothermal route. A series of controlled experiments indicate that the shape and size of as-prepared architectures can be tuned effectively by controlling the reaction conditions, such as reaction time, vanadium sources, different organic additives, and the molar ratio of organic additive trisodium citrate (Cit(3-)):Y(3+). It is found that Cit(3-) as a ligand and shape modifier has the dynamic effect by adjusting the growth rate of different facets under different experimental conditions, resulting in the formation of various geometries of the final products. The possible formation mechanisms for products with diverse architectures have been presented in detail. Additionally, we systematically investigate the luminescent properties of the YVO(4):Ln(3+) (Ln = Eu, Dy, Sm, and Er). Because of an efficient energy transfer from vanadate groups to dopants, YVO(4):Ln(3+) (Ln = Eu, Dy, Sm, and Er) phosphors showed their strong characteristic emission under ultraviolet excitation and low-voltage electron beam excitation. The ability to generate YVO(4) nano/microstructures with diverse shapes, multicolor emission, and higher quantum efficiency provides a great opportunity for systematically evaluating their luminescence properties, as well as fully exploring their applications in many types of color display fields.

Eu3+/Tb3+-doped La2O2CO3/La2O3 nano/microcrystals with multiform morphologies: facile synthesis, growth mechanism, and luminescence properties.

LaCO(3)OH nano/microcrystals with a variety of morphologies/sizes including nanoflakes, microflowers, nano/microrhombuses, two-double microhexagrams sandwichlike microspindles, and peach-nucleus-shaped microcrystals have been synthesized via a facile homogeneous precipitation route under mild conditions. A series of controlled experiments indicate that the pH values in the initial reaction systems, carbon sources, and simple ions (NH(4)(+) and Na(+)) were responsible for the shape determination of the LaCO(3)OH products. A possible formation mechanism for these products with diverse architectures has been presented. After annealing at suitable temperatures, LaCO(3)OH was easily converted to La(2)O(2)CO(3) and La(2)O(3) with the initial morphologies. A systematic study on the photoluminescence and cathodoluminescence properties of Eu(3+)- or Tb(3+)-doped La(2)O(2)CO(3)/La(2)O(3) samples has been performed in detail. The excitation and site-selective emission spectra were recorded to investigate the microstructure, site symmetry, and difference in the (5)D(0) → (7)F(2) transition of Eu(3+) ions in La(2)O(2)CO(3) and La(2)O(3) host lattices. In addition, the dependence of the luminescent intensity on the morphology for the as-prepared La(2)O(2)CO(3)/La(2)O(3):Ln(3+) (Ln = Eu, Tb) samples has been investigated. The ability of generating diverse morphologies and multiemitting colors for different rare-earth activator ion (Ln = Eu, Tb) doped La(2)O(2)CO(3)/La(2)O(3) nano/microstructures provides a great opportunity for the systematic evaluation of morphology-dependent luminescence properties, as well as the full exploration of their application in many types of color display fields.

Self-templated and self-assembled synthesis of nano/microstructures of Gd-based rare-earth compounds: morphology control, magnetic and luminescence properties.

Nearly monodisperse NaGdF(4) and GdF(3) nanowires/nanorods as well as GdBO(3) microplates/microflowers have been successfully prepared by a designed chemical conversion approach using Gd(OH)(3) nanowires/nanorods as precursors via a facile hydrothermal approach. The Gd(OH)(3) nanowires/nanorods precursors were prepared through a simple hydrothermal process, which then served as sacrificial templates for the fabrication of NaGdF(4) and GdF(3) nanowires/nanorods as well as GdBO(3) microplates/microflowers by a hydrothermal process. The possible formation mechanisms for the corresponding Gd(3+)-based various products are presented in detail. We have investigated the magnetic properties of the NaGdF(4), GdF(3), and GdBO(3) samples. The as-obtained Eu(3+) doped NaGdF(4), GdF(3), and GdBO(3) samples show the strong characteristic red emission of Eu(3+) under ultraviolet excitation. Moreover, the luminescence colors of the Eu(3+) and Tb(3+) co-doped GdBO(3) samples can be tuned from red, through orange, yellow and green-yellow, to green by simply adjusting the relative doping concentrations of the activator ions under a single wavelength excitation, which might find potential applications in the fields such as light display systems and optoelectronic devices. More importantly, this simple method is expected to allow the large-scale production of other complex rare-earth compounds with controllable morphologies and sizes, and exploration of the morphology and phase-dependent photoluminescence properties.