Erbium Research Papers - Academia.edu (original) (raw)

In this study, erbia (Er2O3)-doped Bi2O3 ceramics were prepared from sol–gel derived nanocrystalline powders. The morphological properties were investigated by scanning electron microscopy. X-ray diffraction (XRD) analysis was carried out... more

In this study, erbia (Er2O3)-doped Bi2O3 ceramics were prepared from sol–gel derived nanocrystalline powders. The morphological properties were investigated by scanning electron microscopy. X-ray diffraction (XRD) analysis was carried out in order to characterize the phase and crystal structure of the powder samples. Temperature dependent electrical properties were determined by thermogravimetry/differential thermal analyzer (TG/DTA) and 4-point probe techniques. The stable fluorite face centered cubic δ-type phase was observed at room temperature from the XRD result, which was supported by the DTA and temperature dependent electrical conductivity measurements. Electrical conductivity results indicate that there is a transition approximately at 650 °C, which can be attributed to an order–disorder transition (ODT). The activation energy values obtained from the Arrhenius approach for heating and cooling process were presented. Two regimes, corresponding to high temperature region (HTR) and low temperature region (LTR), were observed. As a result of morphological changes during the ODT, the electrical conductivity modifies and the activation energies are different for studied sample at HTR and LTR.

In the present work we have synthesized the Er(3+)/Yb(3+) codoped barium titanate phosphor via co-precipitation method and studied its upconversion emission properties. The prepared BaTiO3 powder was found in cubic phase as a major... more

In the present work we have synthesized the Er(3+)/Yb(3+) codoped barium titanate phosphor via co-precipitation method and studied its upconversion emission properties. The prepared BaTiO3 powder was found in cubic phase as a major component and having good crystallinity revealed by the XRD analysis. Optical band gap of the cubic barium titanate was calculated using the diffuse reflectance absorption spectrum. Good green upconversion emission is observed from the samples when excited by 980 nm diode laser. The variation in upconversion emission intensity is studied with the increase in excitation power as well as temperature of the sample. It is found that the emission bands centred at 524 and 548 nm are thermally coupled and can act as a temperature sensor in the 300-480 K temperature range.

We present a simple method for preparing water dispersible NaGdF4: Yb3+, Er3+/silica/gold nanoparticles. The emission intensity and color of the upconverting cores are modulated by the plasmonic absorbance and field enhancement from the... more

We present a simple method for preparing water dispersible NaGdF4: Yb3+, Er3+/silica/gold nanoparticles. The emission intensity and color of the upconverting cores are modulated by the plasmonic absorbance and field enhancement from the gold nanoparticles. The applicability of hybrid NPs for multi-modal bioimaging probes is illustrated by in vitro confocal microscopy of living cancer cells.

The three new complexes Tp(Py)Ln(CH3CO2)2(H2O) (Ln = Eu (1), Gd(2), or Tb (3)) were prepared and characterized crystallographically. In the crystal lattices of these complexes, separate molecules are connected in infinite chains by... more

The three new complexes Tp(Py)Ln(CH3CO2)2(H2O) (Ln = Eu (1), Gd(2), or Tb (3)) were prepared and characterized crystallographically. In the crystal lattices of these complexes, separate molecules are connected in infinite chains by π-stacking interactions. Complexes 1 and 3 display intense photoluminescence and triboluminescence (red and green respectively), while compound 3 exhibits electroluminescence commencing at 9 V in an ITO/PVK/3/Al device (ITO = indium-tin oxide, PVK = poly(N-vinylcarbazole)). A series of Eu/Tb-doped Gd compounds was prepared by cocrystallization from mixtures of 1 and 2 or 2 and 3, respectively. It was shown that π-stacking interactions are involved in increasing the efficiency of energy transfer from the gadolinium complex to emitting [Tp(Py)Eu](2+) or [Tp(Py)Tb](2+) centers, and this energy transfer occurs through hundreds of molecules, resembling the process of energy harvesting in chloroplast stacks.

Five different samples of Sr-based Er-doped hydroxyapatites (HAps) in the dissimilar quantities like 0, 0.35, 0.70, 1.05 and 1.40 at% were produced via a wet chemical process. The prepared samples were investigated experimentally by... more

Five different samples of Sr-based Er-doped hydroxyapatites (HAps) in the dissimilar quantities like 0, 0.35, 0.70, 1.05 and 1.40 at% were produced via a wet chemical process. The prepared samples were investigated experimentally by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared (FTIR) spectroscopy, differential thermal analysis (DTA), and in vitro bio-compatibility tests. In addition, the density of states (DOS) and band structures were investigated theoretically. It was found that the presence of Er as a dopant affected the lattice parameters, while the EDX measurements confirmed that the presence of Er at various concentrations caused a Ca-deficiency because the addition of Er decreased the Calcium/Phosphorus molar ratio from 1.67 to 1.61. For all samples, the single-phase distribution of HAp was observed. The crystallinity percentage of the samples was found to be 89% or more according to two different methods. The calculations with respect to Scherrer and Williamson-Hall methods showed that the crystallite sizes of the samples were found to be in the ranges of 29-34 nm and 25-42 nm, respectively. DTA investigations revealed that all samples exhibited thermal stability in the temperature range of 25°C-1000°C. No remarkable morphological alterations were observed. Furthermore, the theoretical studies confirmed that the band structures narrowed with an increase in Er concentration.

This is a study on the design of variable gain-flattened erbium-doped fiber amplifier operating in L-band transmission window. Four amplifiers divided into five stages became the basis of the design with distributed pumping configuration.... more

This is a study on the design of variable gain-flattened erbium-doped fiber amplifier operating in L-band transmission window. Four amplifiers divided into five stages became the basis of the design with distributed pumping configuration. A dispersion compensating module was incorporated into the architecture as a way to combat dispersion. The amplifier was able to generate variable gain from 15 up to 30 dB under different input signal powers with a maximum output power of 23 dBm. Excellent gain flatness averaging around 0.8 dB was accomplished while four-wave mixing effect was significantly reduced.

Limited information is available regarding the adhesion to eroded dentin. This study aims to evaluate the effect of different surface treatments on eroded dentin morphology and on microtensile bond strength (μTBS) of adhesive systems to... more

Limited information is available regarding the adhesion to eroded dentin. This study aims to evaluate the effect of different surface treatments on eroded dentin morphology and on microtensile bond strength (μTBS) of adhesive systems to this substrate. Ninety-six extracted third molars were randomly divided into eight groups (n = 12) according to the type of surface treatment and the adhesive system: G1 = Control + Clearfil SE Bond [SE], G2 = Diamond bur [DB] + SE, G3 = Er:YAG laser (60 mJ, 2 Hz, 0.12 W, 19.3 J/ cm(2)) + SE, G4 = Er,Cr:YSGG laser (50 mJ, 30 Hz, 1.5 W, 4.5 J/ cm(2)) + SE, G5 = Control + Single Bond [SB], G6 = DB + SB, G7 = Er:YAG + SB, G8 = Er,Cr:YSGG + SB. The erosive cycling was performed by immersion in 0.05 M citric acid (pH 2.3, 10 min, 6x/day) and in supersaturated solution (pH 7.0, 1 h, between acid attacks), during 5 days. Blocks of composite were bonded to the samples according to the manufacturers' instructions. After 24 h-storage in distilled/deionized...

Boron-doped carbon nanotubes have been prepared by chemical vapour deposition of ethyl alcohol doped with B2O3 using a hot-filament system. Multi-wall carbon nanotubes of diameters in the range of 30 – 100 nm have been observed by field... more

Boron-doped carbon nanotubes have been prepared by chemical vapour deposition of ethyl alcohol doped with B2O3 using a hot-filament system. Multi-wall carbon nanotubes of diameters in the range of 30 – 100 nm have been observed by field emission scanning electron microscopy (FESEM). Raman measurements indicated that the degree of C-C sp2 order decreased with boron doping. Lowest threshold fields

A new route was recently proposed to modify some spectroscopic properties of rare-earth ions in silica-based fibers. We had shown the incorporation of erbium ions in amorphous dielectric nanoparticles, grown in fiber preforms. Here we... more

A new route was recently proposed to modify some spectroscopic properties of rare-earth ions in silica-based fibers. We had shown the incorporation of erbium ions in amorphous dielectric nanoparticles, grown in fiber preforms. Here we present the achieved stabilization of nanometric erbium-doped dielectric nanoparticles within the core of silica fibers. We present the nanoparticle dimensional characterization in fiber samples. We also show the spectroscopic characterization of erbium in preform samples with similar nanoparticle size and composition. This new route could have important potentials in improving rare-earth-doped fiber amplifiers and laser sources.

To evaluate the efficacy of Erbium doped glass fiber laser in patients undergoing nasal septal cartilage reshaping. A prospective study was conducted in patients undergoing laser nasal septal cartilage reshaping. Microsurgical sponges... more

To evaluate the efficacy of Erbium doped glass fiber laser in patients undergoing nasal septal cartilage reshaping. A prospective study was conducted in patients undergoing laser nasal septal cartilage reshaping. Microsurgical sponges soaked in a tetracaine solution plus adrenaline were applied in each side of the nose for ten minutes before the procedure. The cartilage of nasal septum was straightened and fixed in the median position using a modified nasal speculum. An optothermomechanical contactor with transparent indenter and thermocouple sensor was placed on septal regions of maximum mechanical stress. Patients were asked to evaluate the severity of pain during the procedure on a visual analog scale. A rhinomanometric evaluation was conducted preoperatively and postoperatively. All patients were asked to evaluate the improvement of their symptoms. All patients' data and potential complications were entered in a database and were statistically assessed. Our series consisted ...

Upconversion nanoparticles (UCNPs), which are generated by doping with rare earth (RE) metals, are increasingly used for bioimaging because of the advantages they hold over conventional fluorophores. However, because pristine RE... more

Upconversion nanoparticles (UCNPs), which are generated by doping with rare earth (RE) metals, are increasingly used for bioimaging because of the advantages they hold over conventional fluorophores. However, because pristine RE nanoparticles (NPs) are unstable in acidic physiological fluids (e.g., lysosomes), leading to intracellular phosphate complexation with the possibility of lysosomal injury, it is important to ensure that UCNPs are safely designed. In this study, we used commercially available NaYF4:Er/Yb UCNPs to study their stability in lysosomes and simulated lysosomal fluid. We demonstrate that phosphate complexation leads to REPO4 deposition on the particle surfaces and morphological transformation. This leads to a decline in upconversion fluorescence efficiency as well as inducing pro-inflammatory effects at the cellular level and in the intact lung. In order to preserve the imaging properties of the UCNPs as well as improve their safety, we experimented with a series o...

L-band gain improvement through usage of secondary pumping sources in the form of broadband noise (amplified spontaneous emission, ASE) is conducted. For an L-band amplifier system employing ASE to improve gain, pumping the system... more

L-band gain improvement through usage of secondary pumping sources in the form of broadband noise (amplified spontaneous emission, ASE) is conducted. For an L-band amplifier system employing ASE to improve gain, pumping the system counter-directionally with ASE while the 980-nm pump is being used in a co-propagating configuration would yield the best overall performance in terms of gain and noise figure. For high power applications, the 980-nm and ASE sources must be counter-directionally pumped to the direction of the L-band signal. Gain improvement of 1570-nm signal in between 6 and 8.5 dB is attained at 12 mW of 980-nm pump laser.

An efficient Brillouin/erbium fiber laser, which operates in the 1600-nm (L-band) region, is demonstrated for potential applications in future dense-wavelength division multiplexing communication systems. The laser configuration consists... more

An efficient Brillouin/erbium fiber laser, which operates in the 1600-nm (L-band) region, is demonstrated for potential applications in future dense-wavelength division multiplexing communication systems. The laser configuration consists of an L-band EDFA (to enable L-band amplification) where two 3-dB couplers take a portion of the generated BEFL signal and re-inject it into the single-mode fiber in order to seed a cascaded BEFL line in the same direction as the first BEFL line. An efficient BEFL can be obtained by recycling backward a 1550-nm-band amplified spontaneous emission as a secondary pump source for the unpumped EDF in the L-band EDFA section. As a result, the lasing threshold is reduced and slope efficiency is improved. A stable and strong laser comb of up to five lines with 10-GHz spacing has been obtained with a Brillouin pump of 4.8 mW and a 980-nm pump of 92 mW. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 506–508, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10650

We demonstrate the effect of inversion population ratio mediated by 980 nm pumping band on the gain spectra of a gain-flattened Erbium-doped fiber amplifier. The gain equalizing filter was designed at 977 nm and the amplifier was built in... more

We demonstrate the effect of inversion population ratio mediated by 980 nm pumping band on the gain spectra of a gain-flattened Erbium-doped fiber amplifier. The gain equalizing filter was designed at 977 nm and the amplifier was built in the four-stage arrangement. In the pumping structure, the 1480 nm lasers were maintained in the final gain block while the 980 nm band lasers were utilized in the first three blocks. These laser sources were arranged at several combinations of 977 and 980 nm wavelengths. Within these 3 nm spectrum, an absorption cross-section difference around 0.32 × 10-25 m2 contributed to a dispensable gain variation up to 3-dB. These inequalities were the results of variations in population inversion induced by the pump wavelength discrepancy. The findings show the importance of designing a filter at the specific absorption wavelength to allow the operation of consistent gain level.

Two novel mononuclear neodymium alkoxides [Nd{OC-(C 14 H 11 S 2 )} 3 (thf) 3 ]·thf (9) and [Nd{OC(C 16 H 13 S)} 3 (thf) 3 ]·thf (10) have been prepared by the reaction between Nd[N(SiMe 3 ) 2 ] 3 and the tertiary alcohols HO-C(C 14 H 11 S... more

Two novel mononuclear neodymium alkoxides [Nd{OC-(C 14 H 11 S 2 )} 3 (thf) 3 ]·thf (9) and [Nd{OC(C 16 H 13 S)} 3 (thf) 3 ]·thf (10) have been prepared by the reaction between Nd[N(SiMe 3 ) 2 ] 3 and the tertiary alcohols HO-C(C 14 H 11 S 2 ) (3) and HO-C(C 16 H 13 S) (4). The geometry around the neodymium metal is almost octahedral with a facial ligand arrangement similar to [Nd{OC(C 8 H 5 S 2 ) 3 } 3 (thf) 3 ]·4thf (5), [Nd(OC-(C 4 H 3 S) 3 } 3 (thf) 3 ]·thf (7) and Er[OC(C 4 H 3 S) 3 ] 3 (thf) 3 (8) (X-ray diffraction on single crystals). The cyclic voltammograms of a series of neodymium and erbium alkoxides indicate that the electrochemical properties are essentially dominated by the organic ligands. In comparison to the carbinols HOC(C 8 H 5 S 2 ) 3 (1), HO-C(C 4 H 3 S) 3 (2), HO-C(C 14 H 11 S 2 ) (3) or HO-C(C 16 H 13 S) (4), the oxidation peak potentials of the thienyl units for the neodymium alkoxides [Nd{OC(C 8 H 5 S 2 ) 3 } 3 -(thf) 3 ]·4thf (5), [Nd{OC(C 4 H 3 S) 3 } 3 (thf) 3 ]·thf (7), [Nd{OC-(C 14 H 11 S z )} 3 (thf) 3 ]·thf (9) and [Nd{OC(C 16 H 13 S)} 3 (thf) 3 ]·thf (10) are marginally shifted towards higher values by 0.03-0.10V, whereas for Er[OC(C 8 H 5 S 2 ) 3 ] 3 (thf) (6) and Er-[OC(C 4 H 3 S) 3 ] 3 (thf) 3 (8) a decrease of these potentials is noticed. Repetitive cyclic voltammetry does not generate polymeric films for 7-10, as found for the free organic ligands 2-4. Contrarily, the mononuclear precursors [Nd{OC(C 8 H 5 S 2 ) 3 } 3 -(thf) 3 ]·4thf (5) and Er[OC(C 8 H 5 S 2 ) 3 ] 3 (thf) (6) are electro-oxidized and electro-active polymer films are obtained and characterized. To investigate the positions of the excited states of the ligands, emission spectra of the carbinols 1-4 have been recorded. The luminescence studies of the neodymium alkoxides reveal an energy transfer from the ligand to the metal centre with a remarkable Nd emission efficiency upon ligand excitation in the case of 5.

Rational combination of different functional lanthanide materials within a single nanocrystal presents a feasible way to develop a multifunctional nanoplatform for various biomedical applications. The conventional methods of synthesizing... more

Rational combination of different functional lanthanide materials within a single nanocrystal presents a feasible way to develop a multifunctional nanoplatform for various biomedical applications. The conventional methods of synthesizing and integrating two kinds of material together generally involve laborious procedures, whilst codoping different functional ions inside a single lanthanide nanocrystal usually results in a decrease in both its fluorescence and its magnetic resonance relaxivity. Here, we present a seed-mediated synthetic route to prepare core-shell structured NaY F(4):Y b, Er/NaGdF(4) nanocrystals. Epitaxial growth of a gadolinium layer on an upconversion lanthanide seed not only improves its upconversion fluorescence, but also creates a paramagnetic shell with high magnetic resonance relaxivity. The prepared nanocrystals are uniform in size, stable in water and easy for conjugation after modification, which may have the potential to serve as a versatile imaging tool for smart detection or diagnosis in future biomedical engineering.