Listar por autoría "1c125953-5585-42d8-958f-67fcefda714b"

Mostrando ítems 1-20 de 28

    • openAccess   A combined theoretical and experimental study of electronic structure and optical properties of β-ZnMoO4 microcrystals 

      Cavalcante, Laécio Santos; Moraes, E.; Almeida, M.A.P.; Dalmaschio, C.J.; Batista, N.C.; Varela, José A.; Longo, Elson; Siu Li, Maximo; Andres, Juan; Beltran, Armando Elsevier (2013)
      In this paper, a combined theoretical and experimental study on the electronic structure and photoluminescence (PL) properties of beta zinc molybdate ( -ZnMoO4) microcrystals synthesized by the hydrothermal method has ...

    • closedAccess   A description of the formation and growth processes of CaTiO3 mesocrystals: a joint experimental and theoretical approach 

      Moreira, Mario Lucio; Bordin, José Rafael; Andres, Juan; Varela, José A.; Longo, Elson Royal Society of Chemistry (2020)
      In this paper, we report on a combined experimental and theoretical study conducted in order to rationalize the formation and growth mechanism of CaTiO3 mesocrystals through the microwave-assisted hydrothermal synthesis ...

    • openAccess   A DFT Study of Structural and Electronic Properties of ZnS Polymorphs and its Pressure-Induced Phase Transitions 

      La Porta, Felipe A.; Gracia, Lourdes; Andres, Juan; Sambrano, Julio; Varela, José A.; Longo, Elson John Wiley & Sons (2014)
      A systematic first-principles investigation, by using the density functional formalism with the nonlocal B3LYP approximation including a long-range dispersion correction, has been performed to calculate the structural and ...

    • closedAccess   A Joint Experimental and Theoretical Study on the Nanomorphology of CaWO4 Crystals 

      Longo, V. M.; Gracia, Lourdes; Stroppa, Daniel G.; Cavalcante, Laécio Santos; Orlandi, Marcelo; Ramírez, Antonio J.; Leite, Edson R.; Andres, Juan; Beltran, Armando; Varela, José A.; Longo, Elson ACS (2011-08)
      By the joint use of experimental techniques such as field emission scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HR-TEM) and ab initio ...

    • closedAccess   A relationship between structural and electronic order–disorder effects and optical properties in crystalline TiO2 nanomaterials 

      Silva Junior, E.; La Porta, Felipe A.; Liu, M.S.; Andres, Juan; Varela, José A.; Longo, Elson Royal Society of Chemistry (2015)
      The focus of this paper is on the analysis of the structural and electronic order–disorder effects at long, medium and short ranges of titanium dioxide (TiO2) nanoparticles synthesized by the sol–gel process followed by ...

    • closedAccess   A theoretical study on the photoluminescence of SrTiO<sub>3</sub> 

      Gracia, Lourdes; Andres, Juan; Longo, V. M.; Varela, José A.; Longo, Elson Elsevier (2010)
      This Letter deals with the assignment of photoluminescence (PL) emission spectra of SrTiO<sub>3</sub>. Ideal and distorted structures of SrTiO <sub>3</sub> model systems have been selected to localize and characterize at ...

    • openAccess   Correlation between structural and electronic order-disorder effects and optical properties in ZnO nanocrystals 

      La Porta, Felipe A.; Andres, Juan; Vismara, M. V. G.; Graeff, C. F. O.; Sambrano, Julio; Li, Maximo Siu; Varela, José A.; Longo, Elson Royal Society of Chemistry (2014-10)
      The correlation between structural and electronic order–disorder effects in understanding the optical properties of flower-like ZnO nanocrystals synthesized by the microwave-assisted hydrothermal method at low temperatures ...

    • openAccess   Direct in situ observation of the electron-driven synthesis of Ag filaments on a-Ag2WO4 crystals 

      Longo, Elson; Cavalcante, Laécio Santos; Volanti, Diogo P.; Gouveia, Amanda; Longo, V. M.; Varela, José A.; Orlandi, Marcelo; Andres, Juan Nature Publishing group (2013)
      In this letter, we report, for the first time, the real-time in situ nucleation and growth of Ag filaments on α-Ag2WO4 crystals driven by an accelerated electron beam from an electronic microscope under high vacuum. We ...

    • openAccess   Effect of Pressure-Assisted Heat Treatment on Photoluminescence Emission of α-Bi2O3 Needles 

      Schmidt, Samara; Kubaski, Evaldo T.; Volanti, Diogo P.; Sequinel, Thiago; Bezzon, Vinicius Danilo N.; Beltran, Armando; Tebcherani, Sergio M.; Varela, José A. American Chemical Society (2015-10)
      Materials with high photoluminescence (PL) intensity can potentially be used in optical and electronic devices. Although the PL properties of bismuth(III) oxide with a monoclinic crystal structure (α-Bi2O3) have been ...

    • openAccess   Experimental and theoretical approach of nanocrystalline TiO2 with antifungal activity 

      Longo, V. M.; Picon, Francini C.; Zamperini, Camila; Albuquerque, Anderson R.; Sambrano, Julio; Vergani, Carlos; Machado Maciel, Ana Lúcia; Andres, Juan; Hernandes, Antônio C.; Varela, José A.; Longo, Elson Elsevier (2013-07-09)
      Using a solvothermal method for this research we synthesized nanocrystalline titanium dioxide (nc-TiO2) anatase particles with a mean diameter of 5.4 nm and evaluated their potential antifungal effect against planktonic ...

    • closedAccess   Hierarchical Assembly of CaMoO4 Nano-Octahedrons and Their Photoluminescence Properties 

      Longo, V. M.; Cavalcante, Laécio Santos; Paris, Elaine Cristina; Sczancoski, Júlio César; Pizani, Paulo Sergio; Siu Li, Maximo; Andres, Juan; Longo, Elson; Varela, José A. ACS (2011-03)
      Hierarchical assemblies of CaMoO4 (CM) nano-octahedrons were obtained by microwave-assisted hydrothermal synthesis at 120 °C for different times. These structures were structurally, morphologically and optically characterized ...

    • openAccess   Intercalation processes and diffusion paths of lithium ions in spinel-type structured Li1+xTi2O4: density functional theory study 

      Andres, Juan; Varela, José A.; Longo, Elson; Anicete-Santos, M.; Beltran, Armando; Gracia, Lourdes American Physical Society (2008)
      Intercalation processes and corresponding diffusion paths of Li ions into spinel-type structured Li1+xTi2O4 0 x 0.375 are systematically studied by means of periodic density functional theory calculations for different ...

    • openAccess   Microwave-hydrothermal synthesis of single-crystalline Co3O4 spinel nanocubes 

      Mulinari, Tatiana A.; La Porta, Felipe A.; Andres, Juan; Cilense, Mário; Varela, José A.; Longo, Elson The Royal Society of Chemistry (2013-07-29)
      An efficient microwave-hydrothermal (MAH) method has been developed for the synthesis of highly crystalline Co3O4 spinel nanocubes via beta-Co(OH)(2) without any surfactant assistance. The structure and surface chemical ...

    • openAccess   On the reversed crystal growth of BaZrO3 decaoctahedron: shape evolution and mechanism 

      Moreira, Mario Lucio; Andres, Juan; Mastelaro, Valmor Roberto; Varela, José A.; Longo, Elson Royal Society of Chemistry (2011)
      BaZrO3 (BZO) nanoparticles were nucleated, grown and subsequently self-assembled into a 3D decaoctahedronal architecture via a microwave-assisted hydrothermal (MAH) method. X-Ray diffraction (XRD), field emission scanning ...

    • closedAccess   Photoluminescence in quasi-amorphous Pb0.8X0.2Zr0.53Ti0.47O3 (X = Ca, Sr and Ba) powders: An optical and structural study 

      Longo, V. M.; Silva, M. S.; De Figueiredo, A. T.; Franco, R. W. A.; Vila, Carles; Cilense, Mário; Varela, José A.; Longo, Elson; Andres, Juan Elsevier (2009)
      Crystalline and quasi-amorphous PZT and PZT:X (X = Ca, Sr and Ba) powders were obtained by the polymeric precursor method. Electron paramagnetic resonance (EPR) and photoluminescence (PL) data suggest that the presence of ...

    • openAccess   Photoluminescence Properties of Nanocrystals 

      Cavalcante, Laécio Santos; Sczancoski, Júlio César; Varela, José A.; Longo, Elson; Andres, Juan; Rout, S. K. Hindawi Publishing Corporation (2012)
      Photoluminescence (PL) is an optical phenomenon exhibited by some semiconductor materials when excited by an electromagnetic radiation source. After the excitation and recombination processes, these kinds of materials are ...

    • closedAccess   Photoluminescent behavior of SrZrO<sub>3</sub>/SrTiO<sub>3</sub> multilayer thin films 

      Moreira, Mario Lucio; Andres, Juan; Longo, V. M.; Li, Maximo Siu; Varela, José A.; Longo, Elson Elsevier (2009)
      A detailed investigation was made into the origin of photoluminescence in an alternate multilayer system of SrZrO<sub>3</sub> (SZO) and SrTiO<sub>3</sub> (STO) thin films. XRD and room-temperature PL studies revealed a ...

    • closedAccess   Presence of excited electronic state in CaWO4 crystals provoked by a tetrahedral distortion: An experimental and theoretical investigation. 

      Beltran, Armando; Andres, Juan; Gracia, Lourdes; Longo, V. M.; Cavalcante, Laécio Santos; Avansi, Waldir; Li, Maximo Siu; Mastelaro, Valmor Roberto; Varela, José A.; Longo, Elson © American Institute of Physics (2011-08)
      By combining experimental techniques such as x-ray diffraction, Fourier transform Raman, ultraviolet-visible, x-ray absorption near edge structure, extended x-ray absorption fine structure spectroscopy, and theoretical ...

    • openAccess   Quantum mechanical modeling of excited electronic states and their relationship to cathodoluminescence of BaZrO3 

      Moreira, Mario Lucio; Andres, Juan; Gracia, Lourdes; Beltran, Armando; Montoro, Luciano A.; Varela, José A.; Longo, Elson American Institute of Physics (AIP Publishing LLC) (2013)
      First-principles calculations set the comprehension over performance of novel cathodoluminescence (CL) properties of BaZrO3 prepared through microwave-assisted hydrothermal. Ground (singlet, s*) and excited (singlet s** ...

    • closedAccess   Quantum Mechanics Insight into the Microwave Nucleation of SrTiO3 Nanospheres 

      Moreira, Mario Lucio; Longo, V. M.; Avansi, Waldir; Ferrer, Mateus M.; Andres, Juan; Mastelaro, Valmor Roberto; Varela, José A.; Longo, Elson American Chemical Society (2012)
      An extensive investigation of strontium titanate, SrTiO3 (STO), nanospheres synthesized via a microwave-assisted hydrothermal (MAH) method has been conducted to gain a better insight into thermodynamic, kinetic, and reaction ...