Spectroscopic Studies of the Behavior of Eu3

Hindawi Publishing Corporation Journal of Spectroscopy Volume 2015, Article ID 478329, 7 pages http://dx.doi.org/10.1155/2015/478329 Research Article Spectroscopic Studies of the Behavior of Eu3+ on the Luminescence of Cadmium Tellurite Glasses I. V. García-Amaya,1 Ma. E. Zayas,2 J. Alvarado-Rivera,3 E. Álvarez,1 S. A. Gallardo-Heredia,4 G. A. Limón,5 R. Lozada-Morales,6 and J. Ma. Rincón7 1 Departamento de Fı́sica, Universidad de Sonora, 83000 Hermosillo, SON, Mexico Departamento de Investigación en Fı́sica, Universidad de Sonora, 83000 Hermosillo, SON, Mexico 3 Cátedras Conacyt, Departamento de Fı́sica, Universidad de Sonora, 83000 Hermosillo, SON, Mexico 4 Centro de Investigación y Estudios Avanzados del IPN, Unidad Saltillo, Avenida Industria Metalúrgica No. 1062, Parque Industrial Saltillo-Ramos Arizpe, 25900 Ramos Arizpe, COAH, Mexico 5 Departamento de Ciencias Quı́micas Biológicas y Agropecuarias, Unidad Regional Sur, 85880 Navojoa, SON, Mexico 6 Benemérita Universidad Autónoma de Puebla, Postgrado en Fı́sica Aplicada, Facultad de Ciencias Fı́sico-Matemáticas, Avenida San Claudio y Avenida 18 Sur, Colonia San Manuel, Ciudad Universitaria, 72570 Puebla, PUE, Mexico 7 The Glass-Ceramics Lab., Instituto Eduardo Torroja de Ciencias de la Construcción (CSIC), 28033 Madrid, Spain 2 Correspondence should be addressed to Ma. E. Zayas; Received 31 October 2014; Accepted 20 May 2015 Academic Editor: Carlos Andres Palacio Copyright © 2015 I. V. Garcı́a-Amaya et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The effect of europium doping on the photoluminescence of ZnO-CdO-TeO2 glasses is analyzed. TeO2 -based glasses are of high interest as hosts for laser glasses. The Eu-doped oxide glasses were prepared by the conventional melt-quenching method. Five different concentrations of europium nitrate hexahydrate that varied from 0.3 to 1.5 mol% were used. SEM observations revealed the formation of zinc aluminate spinel and disperse droplets of liquid-liquid phase separation in the glasses. X-Ray diffraction reveals the amorphous structure of the fabricated glasses. FT-IR and Raman spectra show the presence of TeO4 and TeO3+1 /TeO3 units that conform with the glass matrix. Raman spectra evidenced a band located at 1556 cm−1 that can be related to interstitial molecular oxygen in the glass matrix. Photoluminescence of the glasses showed light emission due to the following europiumtransitions from its 5 D2 , 5 D1 , and 5 D0 levels to its 7 F𝐽 manifolds: 5 D2 → 7 F0 (468 nm), 5 D2 → 7 F2 (490 nm), 5 D2 → 7 F3 (511 nm), 5 D1 → 7 F1 (536 nm), 5 D1 → 7 F2 (554 nm), 5 D0 → 7 F0 (579.5 nm), 5 D0 → 7 F1 (592 nm), 5 D0 → 7 F2 (613 nm), 5 D0 → 7 F3 (652 nm), and 5 7 D0 → F4 (490 nm). The estimated decay time, 𝜏, was 0.4 ms for all the glasses. 1. Introduction In general, glasses are good materials as host for luminescent trivalent rare earth ions; they show a wide transparency range and low propagation losses, so they can be used in different types of modern devices such as long optical displays, lasting phosphors, and solid-state lasers [1]. Tellurite glasses are interesting and useful host for luminescent trivalent lanthanide ions, showing maximum vibrational frequencies smaller than those of many other oxide glasses [2, 3]. This characteristic favors and increases the luminescence quantum efficiency from excited states of optically active ions. On the other hand, they are chemically stable and highly homogeneous, with low phonon frequency and high linear refractive index. TeO2 -based glasses are promising materials for their use in nonlinear susceptibility [4, 5] and for the development of fiber and integrated optic amplifiers. In addition, these glasses are potential hosts for infrared emitting rare earth elements and can be used as lasers covering all the telecommunication bands [1, 6]. Luminescence properties and potential applications of Eu3+ have been reported in many types of host materials, for example, silicate, borates, phosphates, vanadates, molybdates, and tungstanates [7–13]. One of the more attractive applications of Eu3+ is regarding 2 Journal of Spectroscopy Table 1: Original batch composition for ZnO-CdO-TeO2 . Label ZnO (% mol) CdO (% mol) TeO2 (% mol) Eu(NO3 )3 ⋅6H2 O (% mol) V1 V2 V3 V4 V5 17 17 17 17 17 32 32 32 32 32 51 51 51 51 51 0.3 0.6 0.9 1.2 1.5 the phenomenon of persistent spectral hole burning [14, 15]. The present investigation is part of a wide research about the study of the ZnO-CdO-TeO2 system doped with rare earth ions. One study has been published earlier in which the structural characterization and optical (PL) and thermal analysis of the matrix containing Eu3+ ion was reported [16]. This research shows the influence of varying the Eu3+ ions content on the photoluminescence properties of a single composition of a ZnO-CdO-TeO2 glass. It is worth to mention that the Eu3+ ions have an effect in the short length ordering of the glass structure. 2. Materials and Methods The glasses were fabricated using zinc oxide (ZnO, Fluka Analytical), cadmium oxide (CdO, 99.5%), tellurium dioxide (TeO2 ≥ 99%), and europium nitrate hexahydrate (Eu (NO3 )3 ⋅6H2 O, 99.99%) from Sigma Aldrich. In Table 1 the nominal composition of the mixtures is presented. The powders were weighted in an OHAUS analytical weighing scale, model GA110 with a precision of 0.0001 g. A series of five glasses doped with Eu3+ ions were obtained varying the concentration of the europium ions. The content of metallic oxides of the glass matrix was fixed and only the concentration of europium nitrate hexahydrate was varied from 0.3 to 1.5% mol (Table 1). The glasses were manufactured by the melt-quenching method in high alumina crucibles at 1000∘ C in a Thermolyne 48000 furnace with a dwell time of 30 minutes. After quenching, the glasses were annealed at 350∘ C for 30 minutes. 2.1. Structural Characterization. X-ray diffraction (XRD) analysis was performed in a Philips 3040 using the Cu K𝛼 line. The glassy material was crushed and milled at a particle size under 30 𝜇m for XRD measurements. Scanning electron microscopic (SEM) was carried out in a Philips XL 30ESEM. The samples were prepared as follows: fresh fractured glass pieces were chemically etched (2 vol% hydrofluoric acid for 10 s) to obtain clean surfaces and then were silver coated for SEM/EDS analysis. The elemental composition distribution of the present phases in the glass was determined by spot analysis by Energy Dispersive X-ray Spectrometry (EDS). Infrared (IR) spectra of the glasses were obtained using a Perkin-Elmer 1600 series FT-IR spectrometer in the range of 4000–400 cm−1 at intervals of 4 cm−1 . Micro-Raman spectroscopy analysis was performed on all samples using a micro-Raman X’plora equipment BX41TF OLYMPUS Table 2: Final co (...truncated)