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Christopher R. Bowen - One of the best experts on this subject based on the ideXlab platform.

  • Freeze cast porous Barium Titanate for enhanced piezoelectric energy harvesting
    Journal of Physics D: Applied Physics, 2018
    Co-Authors: James Roscow, Yan Zhang, Marcin J. Kraśny, R. W. C. Lewis, John Taylor, Christopher R. Bowen
    Abstract:

    Energy harvesting is an important developing technology for a new generation of self-powered sensor networks. This paper demonstrates the significant improvement in the piezoelectric energy harvesting performance of Barium Titanate by forming highly aligned porosity using freeze casting. Firstly, a finite element model demonstrating the effect of pore morphology and angle with respect to poling field on the poling behaviour of porous ferroelectrics was developed. A second model was then developed to understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvesting properties. To compare with model predictions, porous Barium Titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric strain coefficients, d 33. The freeze cast Barium Titanate with 45 vol.% porosity had a d 33 = 134.5 pC N−1 compared to d 33 = 144.5 pC N−1 for dense Barium Titanate. The d 33 coefficients of the freeze cast materials were also higher than materials with uniformly distributed spherical porosity due to improved poling of the aligned microstructures, as predicted by the models. Both model and experimental data indicated that introducing porosity provides a large reduction in the permittivity () of Barium Titanate, which leads to a substantial increase in energy harvesting figure of merit, , with a maximum of 3.79 pm2 N−1 for Barium Titanate with 45 vol.% porosity, compared to only 1.40 pm2 N−1 for dense Barium Titanate. Dense and porous Barium Titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous Barium Titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that predicted by the energy harvesting figures of merit.

  • Freeze cast porous Barium Titanate for enhanced piezoelectric energy harvesting
    Journal of Physics D: Applied Physics, 2018
    Co-Authors: James Roscow, Yan Zhang, Marcin J. Kraśny, R. W. C. Lewis, John Taylor, Christopher R. Bowen
    Abstract:

    Energy harvesting is an important developing technology for a new generation of self-powered sensor networks. This paper demonstrates the significant improvement in the piezoelectric energy harvesting performance of Barium Titanate by forming highly aligned porosity using freeze casting. Firstly, a finite element model demonstrating the effect of pore morphology and angle with respect to poling field on the poling behaviour of porous ferroelectrics was developed. A second model was then developed to understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvesting properties. To compare with model predictions, porous Barium Titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric strain coefficients, d 33. Both model and experimental data indicated that introducing porosity provides a large reduction in the permittivity () of Barium Titanate, which leads to a substantial increase in energy harvesting figure of merit, , with a maximum of 3.79 pm2 N-1 for Barium Titanate with 45 vol.% porosity, compared to only 1.40 pm2 N-1 for dense Barium Titanate. Dense and porous Barium Titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous Barium Titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that predicted by the energy harvesting figures of merit.

Jegor Miladinović - One of the best experts on this subject based on the ideXlab platform.

  • Structural evolution of nanostructured Barium Titanate thin film sol–gel derived
    Journal of Sol-Gel Science and Technology, 2008
    Co-Authors: L. Radonjić, M. Todorović, Jegor Miladinović
    Abstract:

    Ferroelectric nanostructured Barium Titanate (BT) thin films derived by a modified sol–gel process were formed by a deep coating method on Si (100) substrate. In this work was investigated the influence of different types and amounts of water (free water directly added in process and crystalline water from Barium precursors) and of different Barium precursors (hydroxide and acetate) on the gel-structure evolution and the Barium Titanate thin film crystallization. The IR-spectroscopy and X-ray diffraction analysis were used for sample characterization. Experimental results show that crystalline water from Barium hydroxide octahydrate stabilizes the cubic phase of Barium Titanate. Barium Titanate crystallizes in the tetragonal form in thin films when sols were prepared with free water and Ba-acetate or Ba-hydroxide monohydrate as precursors. The type of Ba-precursor used in preparation of sols effects the rate of crystallization of the BT in thin films, making it slower in the case when as precursor was used Ba-acetate than Ba-hydroxides. The prepared BT-thin films demonstrated good adhesion towards substrate and were smooth and uniform.

  • Structural evolution of nanostructured Barium Titanate thin film sol–gel derived
    Journal of Sol-Gel Science and Technology, 2008
    Co-Authors: L. Radonjić, M. Todorović, Jegor Miladinović
    Abstract:

    Ferroelectric nanostructured Barium Titanate (BT) thin films derived by a modified sol–gel process were formed by a deep coating method on Si (100) substrate. In this work was investigated the influence of different types and amounts of water (free water directly added in process and crystalline water from Barium precursors) and of different Barium precursors (hydroxide and acetate) on the gel-structure evolution and the Barium Titanate thin film crystallization. The IR-spectroscopy and X-ray diffraction analysis were used for sample characterization. Experimental results show that crystalline water from Barium hydroxide octahydrate stabilizes the cubic phase of Barium Titanate. Barium Titanate crystallizes in the tetragonal form in thin films when sols were prepared with free water and Ba-acetate or Ba-hydroxide monohydrate as precursors. The type of Ba-precursor used in preparation of sols effects the rate of crystallization of the BT in thin films, making it slower in the case when as precursor was used Ba-acetate than Ba-hydroxides. The prepared BT-thin films demonstrated good adhesion towards substrate and were smooth and uniform.

James Roscow - One of the best experts on this subject based on the ideXlab platform.

  • Freeze cast porous Barium Titanate for enhanced piezoelectric energy harvesting
    Journal of Physics D: Applied Physics, 2018
    Co-Authors: James Roscow, Yan Zhang, Marcin J. Kraśny, R. W. C. Lewis, John Taylor, Christopher R. Bowen
    Abstract:

    Energy harvesting is an important developing technology for a new generation of self-powered sensor networks. This paper demonstrates the significant improvement in the piezoelectric energy harvesting performance of Barium Titanate by forming highly aligned porosity using freeze casting. Firstly, a finite element model demonstrating the effect of pore morphology and angle with respect to poling field on the poling behaviour of porous ferroelectrics was developed. A second model was then developed to understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvesting properties. To compare with model predictions, porous Barium Titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric strain coefficients, d 33. The freeze cast Barium Titanate with 45 vol.% porosity had a d 33 = 134.5 pC N−1 compared to d 33 = 144.5 pC N−1 for dense Barium Titanate. The d 33 coefficients of the freeze cast materials were also higher than materials with uniformly distributed spherical porosity due to improved poling of the aligned microstructures, as predicted by the models. Both model and experimental data indicated that introducing porosity provides a large reduction in the permittivity () of Barium Titanate, which leads to a substantial increase in energy harvesting figure of merit, , with a maximum of 3.79 pm2 N−1 for Barium Titanate with 45 vol.% porosity, compared to only 1.40 pm2 N−1 for dense Barium Titanate. Dense and porous Barium Titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous Barium Titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that predicted by the energy harvesting figures of merit.

  • Freeze cast porous Barium Titanate for enhanced piezoelectric energy harvesting
    Journal of Physics D: Applied Physics, 2018
    Co-Authors: James Roscow, Yan Zhang, Marcin J. Kraśny, R. W. C. Lewis, John Taylor, Christopher R. Bowen
    Abstract:

    Energy harvesting is an important developing technology for a new generation of self-powered sensor networks. This paper demonstrates the significant improvement in the piezoelectric energy harvesting performance of Barium Titanate by forming highly aligned porosity using freeze casting. Firstly, a finite element model demonstrating the effect of pore morphology and angle with respect to poling field on the poling behaviour of porous ferroelectrics was developed. A second model was then developed to understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvesting properties. To compare with model predictions, porous Barium Titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric strain coefficients, d 33. Both model and experimental data indicated that introducing porosity provides a large reduction in the permittivity () of Barium Titanate, which leads to a substantial increase in energy harvesting figure of merit, , with a maximum of 3.79 pm2 N-1 for Barium Titanate with 45 vol.% porosity, compared to only 1.40 pm2 N-1 for dense Barium Titanate. Dense and porous Barium Titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous Barium Titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that predicted by the energy harvesting figures of merit.

L. Radonjić - One of the best experts on this subject based on the ideXlab platform.

  • Structural evolution of nanostructured Barium Titanate thin film sol–gel derived
    Journal of Sol-Gel Science and Technology, 2008
    Co-Authors: L. Radonjić, M. Todorović, Jegor Miladinović
    Abstract:

    Ferroelectric nanostructured Barium Titanate (BT) thin films derived by a modified sol–gel process were formed by a deep coating method on Si (100) substrate. In this work was investigated the influence of different types and amounts of water (free water directly added in process and crystalline water from Barium precursors) and of different Barium precursors (hydroxide and acetate) on the gel-structure evolution and the Barium Titanate thin film crystallization. The IR-spectroscopy and X-ray diffraction analysis were used for sample characterization. Experimental results show that crystalline water from Barium hydroxide octahydrate stabilizes the cubic phase of Barium Titanate. Barium Titanate crystallizes in the tetragonal form in thin films when sols were prepared with free water and Ba-acetate or Ba-hydroxide monohydrate as precursors. The type of Ba-precursor used in preparation of sols effects the rate of crystallization of the BT in thin films, making it slower in the case when as precursor was used Ba-acetate than Ba-hydroxides. The prepared BT-thin films demonstrated good adhesion towards substrate and were smooth and uniform.

  • Structural evolution of nanostructured Barium Titanate thin film sol–gel derived
    Journal of Sol-Gel Science and Technology, 2008
    Co-Authors: L. Radonjić, M. Todorović, Jegor Miladinović
    Abstract:

    Ferroelectric nanostructured Barium Titanate (BT) thin films derived by a modified sol–gel process were formed by a deep coating method on Si (100) substrate. In this work was investigated the influence of different types and amounts of water (free water directly added in process and crystalline water from Barium precursors) and of different Barium precursors (hydroxide and acetate) on the gel-structure evolution and the Barium Titanate thin film crystallization. The IR-spectroscopy and X-ray diffraction analysis were used for sample characterization. Experimental results show that crystalline water from Barium hydroxide octahydrate stabilizes the cubic phase of Barium Titanate. Barium Titanate crystallizes in the tetragonal form in thin films when sols were prepared with free water and Ba-acetate or Ba-hydroxide monohydrate as precursors. The type of Ba-precursor used in preparation of sols effects the rate of crystallization of the BT in thin films, making it slower in the case when as precursor was used Ba-acetate than Ba-hydroxides. The prepared BT-thin films demonstrated good adhesion towards substrate and were smooth and uniform.

Harry A. Atwater - One of the best experts on this subject based on the ideXlab platform.

  • Electrooptic Modulation in Thin Film Barium Titanate Plasmonic Interferometers
    Nano letters, 2008
    Co-Authors: Matthew J. Dicken, Luke A. Sweatlock, Domenico Pacifici, Henri J. Lezec, Kaushik Bhattacharya, Harry A. Atwater
    Abstract:

    We demonstrate control of the surface plasmon polariton wavevector in an active metal−dielectric plasmonic interferometer by utilizing electrooptic Barium Titanate as the dielectric layer. Arrays of subwavelength interferometers were fabricated from pairs of parallel slits milled in silver on Barium Titanate thin films. Plasmon-mediated transmission of incident light through the subwavelength slits is modulated by an external voltage applied across the Barium Titanate thin film. Transmitted light modulation is ascribed to two effects, electrically induced domain switching and electrooptic modulation of the Barium Titanate index.