Papers by Inocencio Benenzuela
Información del artículo Nuevos materiales vitrocerámicos nanoestructurados para aplicaciones ópt... more Información del artículo Nuevos materiales vitrocerámicos nanoestructurados para aplicaciones ópticas.
The 84th Annual Meeting of the Society for American Archaeology, 2019
En este trabajo se realiza un estudio espectroscopico en vidrios fluorindatos dopados con tm3+, h... more En este trabajo se realiza un estudio espectroscopico en vidrios fluorindatos dopados con tm3+, ho3+, er3+ y yb3+.En primer lugar se realiza una revision de los modelos que estudian las propiedades opticas de los iones en solidos y se proponen nuevas aportaciones a aquellos modelos que analizan los procesos de transferencia de energia.Se estudian las propiedades opticas de los iones en muestras con un solo tipo de dopante y con baja concentracion (0.1 mol%), de tal forma que la interaccion entre ellos sea despreciable, dando en cada caso los espectros y los parametros caracteristicos de las transiciones opticas. En muestras con mayor concentracion de dopante la interaccion entre iones es apreciable y se manifiestan procesos de transferencia de energia que son analizados en base a los modelos propuestos. Tambien se estudian los procesos de transferencia de energia y 'upconversion' en muestras codopadas con iones yb3+ y con iones tm3+, ho3+ o er3+ como iones aceptores. Es de destacar los resultados obtenidos en matrices dopadas con iones yb3+ - er3+ en los que los procesos de transferencia y 'backtransfer' son muy eficientes. Ademas, se han realizado medidas de fluorescencia de estrechamiento de linea en iones yb3+ con el fin de analizar los procesos de transferencia de energia entre estos iones.
Revista de la Academia Canaria de Ciencias: = Folia Canariensis Academiae Scientiarum, 1991
Journal of Luminescence, 2016
In this work, the influence of the chlorine ions in the optical and structural properties of hafn... more In this work, the influence of the chlorine ions in the optical and structural properties of hafnium oxide (HfO 2) doped with europium (Eu 3+) and terbium (Tb 3+) are reported. The synthesis was conducted by hydrothermal route at a temperature of 200 °C, with a reaction time of 80 minutes and a concentration of 3 mol% of both dopants, in relation to hafnium in solution. In order to study the influence of acidity on the kinetics of reaction, the pH of the precursor solution was varied in the range of pH=4 to pH=12. X-ray powder diffraction patterns showed that the materials crystallized better under alkaline conditions with pH=11, noting a better crystallinity in the material doped with Eu 3+ showed a better crystallinity that Tb 3+ ions. The characteristic rhombohedral microstructure of HfO 2 in the 2 monoclinic phase was observed in alkaline media. Photoluminescent spectra showed the characteristic peaks of the emissions for both Eu an Tb dopants, where the intensity of the luminescent emission increases by decreasing the concentration of chlorine ions. On the other hand, it was found that radiative life kinetics of the dopant is related to the kinetics of crystallization, and therefore, to the acidity of the precursor solution.
Revista De La Academia Canaria De Ciencias Folia Canariensis Academiae Scientiarum, 1991
Dalton Transactions, 2015
The magnetic properties of two similar Er 3+ complexes have been investigated. [Er(tpm) 3 (bipy)]... more The magnetic properties of two similar Er 3+ complexes have been investigated. [Er(tpm) 3 (bipy)] (Htpm = 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione and bipy = 2,2'-bipyridine) displays thermally activated slow relaxation of magnetisation under a zero direct-current (DC) field. Under an applied H DC field of 1000 G, [Er(tpm) 3 (bipy)] exhibits two thermally activated processes with energy barriers of 9 and 40 K, while [Er(tfa) 3 (bipy)] (Htfa = 4,4,4-trifluoro-1-(2-furyl)-1,3-butanedione) shows only one activated process with a barrier of 15 K. Both compounds are luminescent in the solid state, emitting in the near IR region. † Electronic supplementary information (ESI) available: Vibrational characterization (FTIR and Raman), 1 H-NMR and 13 C-NMR spectroscopic data, TG/DTG/ DTA analysis, UV-Vis absorption and UV-Vis-NIR diffuse reflectance spectra, emission spectrum in the visible region, excitation spectrum, ligand-associated PL decay and static magnetic measurements for the [Er(tfa) 3 (bipy)] complex. Additional AC susceptibility measurements for both [Er(tfa) 3 (bipy)] and [Er(tpm) 3 (bipy)] samples. CCDC 1010428 for [Er(tfa) 3 (bipy)]. For ESI and crystallographic data in CIF or other electronic format see
This work highlights some physical properties on langbeinite K 2 Mg 2 (SO 4 ) 3 :Dy 3 þ sulfates ... more This work highlights some physical properties on langbeinite K 2 Mg 2 (SO 4 ) 3 :Dy 3 þ sulfates which were prepared by high temperature solid state reaction technique. X-ray powder diffraction confirmed the high purity of the obtained phases. These sulfates crystallize in the cubic phase with space group P2 1 3.
Single crystals of Nd 3 þ -doped Co-picromerite has been synthesized by the slow evaporation meth... more Single crystals of Nd 3 þ -doped Co-picromerite has been synthesized by the slow evaporation method. After two weeks on hold, the crystals obtained were characterized by different techniques, indeed X-ray powder diffraction (XRPD) shows that these compounds crystallize in the monoclinic system with space group P21/a. Complete dehydration of the double salt was obtained before reaching 200°C with a phase transition of KS around 570°C. The IR spectroscopic study confirms the vibrational modes of the sulfate groups and water molecules. Exciting at 473 nm, the emission peaks associated with the 4F 5/2 -4I 9/2 , 4F 3/ 2 -4I 9/2 and 4F 3/2 -4I 11/2 transitions were observed. The luminescence decay curve was analyzed in the frame of the Inokuti-Hirayama model in order to obtain the intrinsic lifetime and the energy transfer parameter among Nd 3 þ ions.
In this work, the influence of the chlorine ions in the optical and structural properties of hafn... more In this work, the influence of the chlorine ions in the optical and structural properties of hafnium oxide (HfO 2 ) doped with europium (Eu 3 þ ) and terbium (Tb 3 þ ) are reported. The synthesis was conducted by hydrothermal route at a temperature of 200°C, with a reaction time of 80 min and a concentration of 3 mol% of both dopants, in relation to hafnium in solution. In order to study the influence of acidity on the kinetics of reaction, the pH of the precursor solution was varied in the range of pH¼ 4 to pH¼12. Xray powder diffraction patterns showed that the materials crystallized better under alkaline conditions with pH ¼11, noting a better crystallinity in the material doped with Eu 3 þ showed a better crystallinity that Tb 3 þ ions. The characteristic rhombohedral microstructure of HfO 2 in the monoclinic phase was observed in alkaline media. Photoluminescent spectra showed the characteristic peaks of the emissions for both Eu an Tb dopants, where the intensity of the luminescent emission increases by decreasing the concentration of chlorine ions. On the other hand, it was found that radiative life kinetics of the dopant is related to the kinetics of crystallization, and therefore, to the acidity of the precursor solution.
Yb 3+ -doped langbeinite salts were prepared by the solid solution method. X-ray diffraction patt... more Yb 3+ -doped langbeinite salts were prepared by the solid solution method. X-ray diffraction patterns and vibrational spectroscopy confirmed that all obtained phases are highly pure, iso-structural and they crystallize in the cubic system with the space group P2 1 3. The emission luminescence comes from the 2 F 5/2 ? 2 F 7/2 transition of Yb 3+ ions. Moreover, intense blue cooperative emission was observed at 476 nm under excitation in the near infrared at 975 nm.
Porous perovskite Chemical looping combustion and calcium manganese A B S T R A C T New modified ... more Porous perovskite Chemical looping combustion and calcium manganese A B S T R A C T New modified calcium manganese (CM) perovskite structures applicable in chemical looping combustion were synthesized in this study. These modifications were applied by doping the A-site with lanthanum and strontium and B-site by iron and zirconium (CLMF, CLMZ, CSMF, and CSMZ). TGA, XRD, SEM and BET techniques have been used to characterize the prepared structures. According to the results obtained from TGA analysis, the oxygen capacity of the samples ranged between 1.2 for CLMZ and 1.75 for CSMF. All prepared samples showed to possess a porous surface and the perovskites phase formation was confirmed by XRD results. Iodometric titration experiments were also conducted for evaluating the manganese ion charge and its variability in association with different doping elements. Reactivity and oxygen uncoupling behaviors of the prepared samples were also evaluated using a fluidized bed chemical looping reactor using methane as the fuel at four different temperatures (800, 850, 900, 950 C).
We experimentally reporton optical binding of many glass particles in air that levitate in a sing... more We experimentally reporton optical binding of many glass particles in air that levitate in a single optical beam. A diversity of particle sizes and shapes interact at long range in a single Gaussian beam. Our system dynamics span from oscillatory to random and dimensionality ranges from 1 to 3D. The low loss for the center of mass motion of the beads could allow this system to serve as a standard many body testbed, similar to what is done today with atoms, but at the mesoscopic scale.
The use of the upconversion emission in Tm 3 þ doped glasses for solar applications has been anal... more The use of the upconversion emission in Tm 3 þ doped glasses for solar applications has been analyzed. The Tm 3 þ ions, that absorb photons from the near infrared range, perform an energy transfer upconversion process from the 3 F 4 intermediate energy level to the 3 H 4 excited state followed by the radiative emission of photons at 800 nm, which correspond to the 3 H 4 -3 H 6 electronic transition. These photons can be absorbed by a silicon solar cell and hence be used in the generation of photocurrent. From the analysis of the rate equations that describes the emission of the 800 nm photons, the dependence of the External Quantum Efficiency with the solar concentration value has been obtained.
Ytterbium-doped tungsten tellurite glasses have been prepared and studied their cooperative upcon... more Ytterbium-doped tungsten tellurite glasses have been prepared and studied their cooperative upconverted luminescence and radiative energy transfer properties. In a 3.0 mol% Yb 2 O 3 -doped glass, nearinfrared emission band is peaked at around 977 nm with a full width at half maximum of around 15 nm. This glass emits blue-green upconverted emission under 980 nm excitation due to cooperative processes involving two interacting Yb 3 þ ions. The upconverted emission band is centered at around 502 nm with a bandwidth of around 45 nm. Power dependence of cooperative emission intensity and the temporal evolutions of the near-infrared and blue-green emissions confirm the presence of cooperative luminescence. Photoluminescence and lifetimes have been measured by moving the laser excitation from one edge of the sample and found that radiative energy transfer is predominant in 3.0 mol% of Yb 2 O 3 -doped glass. The absorption coefficient obtained from absorption spectrum is in good agreement with that obtained by fitting the curve of luminescence intensity versus distance from the edge of the sample.
Please cite this article in press as: L. Labrador-Páez, et al., Temperature dependence of the whi... more Please cite this article in press as: L. Labrador-Páez, et al., Temperature dependence of the whispering gallery modes obtained in a glass microsphere codoped with Er 3+ -Yb 3+ ions, Sens. Actuators A: Phys. (2015), http://dx.a b s t r a c t A microsphere made from a Strontium Barium Niobate glass codoped with Er3+ and Yb3+ ions is proposed in order to be employed as an optical temperature sensor. By means of the fluorescence intensity ratio technique, the effect of temperature changes in the emission bands of the erbium thermalized levels is characterized. At the same time, the position in wavelength of the whispering gallery modes is altered as a consequence of temperature shifts. The analysis of temperature shifts enables to estimate that the temperature could be obtained with a resolution limit of about 0.01 K.
Single crystals of YAl 3 (BO 3 ) 4 doped with trivalent samarium were grown by the top-seeded hig... more Single crystals of YAl 3 (BO 3 ) 4 doped with trivalent samarium were grown by the top-seeded high temperature solution method and their absorption and emission spectra were investigated. Optical pumping into prominent absorption band around 405 nm feeds the 4 G 5/2 metastable level giving rise to intense visible luminescence distributed in several spectral lines with the most intense line around 600 nm characterized by a branching ratio of 0.42 and peak emission cross section of 0.25 Â 10 À 20 cm 2 . Optical amplification at 600 nm with a gain coefficient of 2.9 cm À 1 was achieved during a pump-and-probe experiment.
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Papers by Inocencio Benenzuela