Fabrication of Ormocer Containing Eu^(3+) Ion and Their Optical Spectra

Eu 3+ ions were incorporated in sol and gel by a sol gel processing using 3 glycidoxypropyltrimethoxysilane (CH 2OCHCH 2O(CH 2) 3Si(OCH 3) 3, GPTMS) and ethyl silicate (TEOS) as precursors. The basic chemical physical properties such as DTA curve, FT IR spectra and specific surface area were recorded. The characteristics of their optical spectra were measured and investigated. The results indicate that the emission intensity of Eu 3+ ion in ormocer is much higher and the global line width is wider than those in SiO 2 gel. The relationship between the composition and structure of gels and the fluorescence intensity and width were discussed. The obtained ormocer shows good mechanical strength, which can be cut and polished in machine without broken.

Controllable synthesis of Eu3+ ions doped Zn（OH）F and ZnO micro-structures:Phase,morphology and luminescence property

Eu3+ions doped Zn(OH)F and ZnO micro-structures with specific morphologies were synthesized by a simple hydrothermal method only through altering the addition amount of NH4F and hexamethylenetetramine(HMT).The phase structure,morphology and luminescence properties of the as-prepared samples were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),photoluminescence(PL)spectra and lifetime.The results indicate that the obtained Zn(OH)F:Eu^3+samples possess net-like and dandelion-like morphologies,which have an identical orthorhombic phase structure.It is found that the addition amount of raw materials such as NH4F and HMT plays a critical role for the formation of Zn(OH)F:Eu^3+.If the addition amounts of NH4F or HMT are reduced by half,the hexagonal ZnO:Eu^3+sample with peanut-like morphology can be obtained.Under the excitation of UV light,both the as-prepared Zn(OH)F:Eu^3+and ZnO:Eu^3+samples exhibit the characteristic emission of the doped Eu^3+.

Spectral Hole-Burning of Eu ^( 3+)∶Y_2SiO_5 Crystal at 579.62 nm

By using an Ar+ ion laser, a tunable Rh 6G dye laser(Linewidth: 0.5 cm -1) and a Coherent 899-21 dye laser as light sources and using a monochromator and a phase-locking amplifier, the optical properties of Eu 3+∶Y_2SiO_5 crystal were detected. Persistent spectral hole burning (PSHB) were also observed in 5D_0-7F_0 transition in the crystal at the temperature of 16 K. For 15 mW dye laser (Wavelength: 579.62 nm) burning the crystal for 0.1 s a spectral hole with about 80 MHz hole width were detected and the hole can been keep for longer than 10 h.

Eu ^(3+) Improving Drought Tolerance But Decreasing ODAP Level in Grass Pea (Lathyrus Sativus L.) Seedlings

Drought tolerance and toxicity variation of grass pea (Lathyrus Sativus L.) were studied in the presence and absence of earth element Eu 3+ under the pot-culture condition. The addition of exogenous Eu 3+ increases the survival days (SD) and lowered the stomatal sensitivity of grass pea seedlings under the decreasing soil moisture from -0.2 MPa to -1 MPa, suggesting that Eu 3+ can improve the ability of grass pea seedlings to tolerate drought. But in this case, Eu 3+ is found to significantly inhibit the increase in contents of plant toxicity β-N-oxalyl-L-a, β-diaminopropionic acid (ODAP) level in leaves. Therefore, the results demonstrate that Eu 3+ application is a potential agronomic approach to improve drought tolerance while lowering the toxicity level in grass pea productivity.

Sorption Characteristics of Rare Earth Element Eu ^(3+) onto Silica-Water Interfaces Studied by Fluorescence Spectroscopy

The sorption of Eu species onto nano-size silica-water interfaces was investigated using fluorescence spectroscopy for pH ranges of 1-8.5 and an initial Eu concentration (C Eu) of 2×10 -4 M. The sorption rate of Eu was initially low, but significantly increased at pH>4. The sorption density of Eu species on a silica surface was ～1.58×10 -7 mol/m2 when the dissolved Eu species were completely sorbed onto silica-water interfaces at pH=～5.8. The sorbed Eu species at pH<6 is aquo Eu 3+, which is sorbed onto silica-water interfaces as an outer-sphere complex at pH<5, but may be sorbed as an inner-sphere bidentate complex at 5<pH<6, due to the decrease of N H 2O to ～6 at pH=6. At pH=6-8.5, Eu(OH)+ 2, Eu(CO 3)+ and Eu(CO 3)- 2 formed in the solutions, and Eu(CO 3)+ is dominant at pH=～7.5. These ions may be sorbed onto silica-water interfaces as inner-sphere bidentate complexes.

A new oxyapatite red phosphor Eu^(3+)-doped Ca_(3)Y_(7)(BO_(4))(SiO_(4))_(5)O:Synthesis,structure and luminescence properties

A series of new oxyapatite red phosphors Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O doped with different concentrations of Eu^(3+)were successfully synthesized by high temperature solid state method.The X-ray diffraction(XRD)Rietveld refinement results show that the structure of the phosphor belongs to space group P6_(3)/m and Eu^(3+)ion replaces Y^(3+)ion.The emission spectrum consists of the characteristic emission peaks corresponding to Eu^(3+)under the excitation of 274 nm and the dominant emission peak is at 614 nm(^(5)D_(0)→^(7)F_(2) of Eu^(3+)).The concentration quenching effect occurs and the optimized Eu^(3+)concentration is 4.0 mol%.The energy level diagram for luminous mechanism is also given and the non-radiative energy transfer mechanism between Eu^(3+)is mainly exchange interaction.The CIE coordinate is close to the ideal red light and the color purity is higher than 99.79%.Moreover,the phosphor exhibits moderate thermal stability because the photoluminescence intensity at 423 K is still maintained at higher than 78.97%of that at room temperature.The internal quantum efficiency of Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O:4.0 mol%Eu^(3+)phosphor is 58.2%.A red light emitting diode(LED)device based on it can emit bright red light.The CCT values of the device are basically unchanged when driven by various bias current.The results show that Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O:Eu^(3+)is a new type of oxyapatite red fluorescent material with good comprehensive performances.

Sol-gel method and optical properties of Ca_(12)Al_(14)O_(32)F_2:Eu^(3+) red phosphors

Ca12Al14032F2.＇Eu3＋ red phosphors were prepared by the sol-gel method with CF3COOH as the fluorine source. X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectra, and photoluminescence spectra, as well as thermogravimetric and differential thermal analysis were utilized to characterize the samples. All the samples were single phase with a cubic structure. The as-obtained Ca12Al14Oa2F2：Eu3＋ red phosphors consisted of nanoparticles with sizes of approximately 40-100 nm. Under the excitation of UV light, CalEA114032F2：Eu3＋ exhibited the characteristic emissions of Eu3＋, and the effect of annealing temperature, an- nealing time, and CF3COOH and Eu3＋ concentrations on the luminescence intensity were discussed in detail.