Synthesis of Tenoltrifluoroacetone Composite Doped with Terbium, Dysprosium and Europium Encapsulated in Silica Oxide Matrix

The synthesis of the thenoyltrifluoroacetone compound doped with terbium, dysprosium and europium encapsulated in a silica matrix (TTA:Tb:Dy:Eu@SiO 2 ) were performed by the sol-gel method. The precursors to obtain the vitreous phase (SiO 2 ) were: Tetraethylorthosilicate (TEOS, C 8 H 2 O 4 Si, 98%, Aldrich), and ethyl alcohol (CH 3 CH 2 OH, 99.5%, Meyer), distilled water and 0.05 ml of hydrochloric acid (HCl, Meyer). The sample with molar ratio 20:80 TTA:Tb:Dy:Eu@SiO 2 has the best emission intensity. Thermogravimetric analysis (TGA) shown that silica encapsulated samples decompose at lower temperatures than pure TTA:Tb:Dy:Eu luminescent material. Fourier Transform Infrared (IR-TF) shown the characteristic Si-O-Si bands that are presented at a wavelength of 1049, 853 and 440 cm −1 confirming that the luminescent material is encapsulated in a silica matrix, finally X-ray diffraction (XRD) shown that TTA:Tb:Dy:Eu@SiO 2 composite is amorphous.


Introduction
Luminescent materials are presented in a wide variety of materials such as inorganic crystals, glasses, ceramics and organic compounds [1] because the technological advance of luminescent materials has been growing since the applications that these have are diverse and are used in optoelectronics, medical appli-cations, textiles, and others applications. In this way, the study of organic binders doped with rare earth (such as β-diketones) is growing rapidly since it is possible to increase considerably the intensity of emission of compounds due to the so-called antenna effect [2].
Organic compounds of lanthanides have been widely reported to have desirable properties that show intense narrow-band emissions through efficient intermolecular energy transfer from the binding states to the central metal ions.
The luminescence spectra are greatly intensified by the completion of lanthanide ions with organic ligands. These lanthanide ions form a stable crystalline complex with heterocyclic ligands, such as bipyridyl (bipy) and phenanthroline (phen10) [3] [4] [5]. On the other hand some projects have been reported to obtain low-cost luminescent material, using a silica matrix. Orozco [6], reported the synthesis and characterization of the luminescent and structural properties of zinc sulphide (ZnS) powders, doped with the trivalent Europium ion (Eu 3+ ) and encapsulated in silicon dioxide (SiO 2 ), the luminescent properties of the powders were significantly improved when they were thermally treated, being the experiment nine with the ratio [1:2, 1:2, 8%, 800˚C] the one with the best result. Reyes et al. [7] obtained nanometric powders of BaTiO 3 :Eu 3+ composite materials encapsulated in a SiO 2 matrix they found that is possible to increase the intensity of light emission in the powders, when they are thermally treated at 200˚C for 24 h, according to the photoluminescence tests. Finally Y. Li et al. [8], synthesized TNaGdF 4 :Yb, Er nanoparticles were encapsulated in SiO 2 from the precursor TEOS by the sol-gel method. The light emission intensity of the SiO 2 encapsulation was 5 times higher compared to the NaGdF 4 :Yb nanoparticles. Therefore, it is demonstrated that the coating of ceramic and organic particles in SiO 2 improves the optical properties of the composite materials by increasing the light emission [9] [10] [11]. In this work, we improve this methodology in TTA:Tb:Dy:Eu organic powders.

Methodology
For the samples of the glass-ceramic materials, powders of TTA

Fourier Transform Infrared Spectroscopy (FT-IR)
The

Photoluminescence
Excited emission spectra at 380 nm were performed, as well as the excitation spectra. First, the excitation spectrum is made to determine which is the best wavelength to excite the samples and obtain the highest emission intensity. The results that were obtained for the highest emission were in a length λ = 380 nm, as can be seen in

Chromaticity Diagram
The chromaticity diagrams with their respective emission spectrum are shown

X-Ray Diffraction Spectroscopy (XRD)
The diffractograms presented in Figure 7 show the amorphous behavior of the material TTA:Eu:Dy:Tb@SiO 2 , as well as of TTA:Eu:Dy:Tb, with a crystal size in the order of nanometers. Likewise, a wide band can be observed that presents the composite Dy:Tb@SiO 2 in its different molar relations, where the shoulder grows with intensity in the samples that received thermal treatment at 88˚C, since when the temperature increases, the change of position of the peaks increases due to a possible change of phase. The uniform frames on the surface suggest that a homogeneous molecular base material was obtained by the strong covalent bond in the Si-O-Si networks that belong to a complex and large molecular system [9].

Thermogravimetric Analysis (TGA)
The thermogravimetric analysis of TTA:Eu:Dy:Tb shown in Figure 8 can be di-

Conclusions
The The highest intensity was found at λ = 614 nm where the characteristic transitions 5 D 0  7 F 2 of Eu 3+ appeared, confirming the color it emits is red-orange. The TGA analysis confirms a red-orange emission that tends to decrease with the silica concentration because the TTA:Tb:Dy:Eu@SiO 2 composite decomposes at a lower temperature than when having the TTA:Tb:Dy:Eu material without silica.