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Title: High-fraction brookite films from amorphous precursors

Abstract

Structure-specific synthesis processes are of key importance to the growth of polymorphic functional compounds such as TiO 2, where material properties strongly depend on structure as well as chemistry. The robust growth of the brookite polymorph of TiO 2, a promising photocatalyst, has been difficult in both powder and thin-film forms due to the disparity of reported synthesis techniques, their highly specific nature, and lack of mechanistic understanding. In this work, we report the growth of high-fraction (~95%) brookite thin films prepared by annealing amorphous titania precursor films deposited by pulsed laser deposition. We characterize the crystallization process, eliminating the previously suggested roles of substrate templating and Na helper ions in driving brookite formation. Instead, we link phase selection directly to film thickness, offering a novel, generalizable route to brookite growth that does not rely on the presence of extraneous elements or particular lattice-matched substrates. In addition to providing a new synthesis route to brookite thin films, our results take a step towards resolving the problem of phase selection in TiO 2 growth, contributing to the further development of this promising functional material.

Authors:
 [1];  [2]; ORCiD logo [3];  [4];  [5];  [6]; ORCiD logo [7];  [5]; ORCiD logo [8];  [6];  [5];  [9];  [1]
  1. Oregon State Univ., Corvallis, OR (United States). Dept. of Physics
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States). Applied Energy Programs
  3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Materials Science and Engineering
  4. Colorado School of Mines, Golden, CO (United States). Dept. of Metallurgical and Materials Engineering
  5. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division; Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering
  7. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
  8. SLAC National Accelerator Lab., Menlo Park, CA (United States). Applied Energy Programs; SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
  9. Colorado School of Mines, Golden, CO (United States). Dept. of Metallurgical and Materials Engineering
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1409492
Report Number(s):
NREL/JA-5K00-70535
Journal ID: ISSN 2045-2322
Grant/Contract Number:
AC36-08GO28308; AC02-76SF00515; ACI-1548562; AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; brookite; thin films; precursors; Materials for energy and catalysis; Surfaces, interfaces and thin films

Citation Formats

Haggerty, James E. S., Schelhas, Laura T., Kitchaev, Daniil A., Mangum, John S., Garten, Lauren M., Sun, Wenhao, Stone, Kevin H., Perkins, John D., Toney, Michael F., Ceder, Gerbrand, Ginley, David S., Gorman, Brian P., and Tate, Janet. High-fraction brookite films from amorphous precursors. United States: N. p., 2017. Web. doi:10.1038/s41598-017-15364-y.
Haggerty, James E. S., Schelhas, Laura T., Kitchaev, Daniil A., Mangum, John S., Garten, Lauren M., Sun, Wenhao, Stone, Kevin H., Perkins, John D., Toney, Michael F., Ceder, Gerbrand, Ginley, David S., Gorman, Brian P., & Tate, Janet. High-fraction brookite films from amorphous precursors. United States. doi:10.1038/s41598-017-15364-y.
Haggerty, James E. S., Schelhas, Laura T., Kitchaev, Daniil A., Mangum, John S., Garten, Lauren M., Sun, Wenhao, Stone, Kevin H., Perkins, John D., Toney, Michael F., Ceder, Gerbrand, Ginley, David S., Gorman, Brian P., and Tate, Janet. 2017. "High-fraction brookite films from amorphous precursors". United States. doi:10.1038/s41598-017-15364-y. https://www.osti.gov/servlets/purl/1409492.
@article{osti_1409492,
title = {High-fraction brookite films from amorphous precursors},
author = {Haggerty, James E. S. and Schelhas, Laura T. and Kitchaev, Daniil A. and Mangum, John S. and Garten, Lauren M. and Sun, Wenhao and Stone, Kevin H. and Perkins, John D. and Toney, Michael F. and Ceder, Gerbrand and Ginley, David S. and Gorman, Brian P. and Tate, Janet},
abstractNote = {Structure-specific synthesis processes are of key importance to the growth of polymorphic functional compounds such as TiO2, where material properties strongly depend on structure as well as chemistry. The robust growth of the brookite polymorph of TiO2, a promising photocatalyst, has been difficult in both powder and thin-film forms due to the disparity of reported synthesis techniques, their highly specific nature, and lack of mechanistic understanding. In this work, we report the growth of high-fraction (~95%) brookite thin films prepared by annealing amorphous titania precursor films deposited by pulsed laser deposition. We characterize the crystallization process, eliminating the previously suggested roles of substrate templating and Na helper ions in driving brookite formation. Instead, we link phase selection directly to film thickness, offering a novel, generalizable route to brookite growth that does not rely on the presence of extraneous elements or particular lattice-matched substrates. In addition to providing a new synthesis route to brookite thin films, our results take a step towards resolving the problem of phase selection in TiO2 growth, contributing to the further development of this promising functional material.},
doi = {10.1038/s41598-017-15364-y},
journal = {Scientific Reports},
number = 1,
volume = 7,
place = {United States},
year = 2017,
month =
}

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  • Structure-specific synthesis processes are of key importance to the growth of polymorphic functional compounds such as TiO 2, where material properties strongly depend on structure as well as chemistry. The robust growth of the brookite polymorph of TiO 2, a promising photocatalyst, has been difficult in both powder and thin-film forms due to the disparity of reported synthesis techniques, their highly specific nature, and lack of mechanistic understanding. In this work, we report the growth of high-fraction (~95%) brookite thin films prepared by annealing amorphous titania precursor films deposited by pulsed laser deposition. We characterize the crystallization process, eliminating themore » previously suggested roles of substrate templating and Na helper ions in driving brookite formation. Instead, we link phase selection directly to film thickness, offering a novel, generalizable route to brookite growth that does not rely on the presence of extraneous elements or particular lattice-matched substrates. In addition to providing a new synthesis route to brookite thin films, our results take a step towards resolving the problem of phase selection in TiO 2 growth, contributing to the further development of this promising functional material.« less
  • Structure-specific synthesis processes are of key importance to the growth of polymorphic functional compounds such as TiO 2, where material properties strongly depend on structure as well as chemistry. The robust growth of the brookite polymorph of TiO 2, a promising photocatalyst, has been difficult in both powder and thin-film forms due to the disparity of reported synthesis techniques, their highly specific nature, and lack of mechanistic understanding. In this work, we report the growth of high-fraction (~95%) brookite thin films prepared by annealing amorphous titania precursor films deposited by pulsed laser deposition. We characterize the crystallization process, eliminating themore » previously suggested roles of substrate templating and Na helper ions in driving brookite formation. Instead, we link phase selection directly to film thickness, offering a novel, generalizable route to brookite growth that does not rely on the presence of extraneous elements or particular lattice-matched substrates. In addition to providing a new synthesis route to brookite thin films, our results take a step towards resolving the problem of phase selection in TiO 2 growth, contributing to the further development of this promising functional material.« less
  • Superconducting thin films of Y-Ba-Cu oxide have been prepared on yttria-stabilized zirconia substrates using metal trifluoroacetate spin-on precursors. The films exhibit an extremely sharp resistive transition with zero resistance at temperatures as high as 94 K. The superconducting phase is formed by a three-step process: (a) decomposition of the spun-on trifluoroacetate film to the fluorides, (b) conversion of the fluorides to oxides by reacting with water vapor, and (c) annealing followed by slow cooling in oxygen. The properties of the films depend on the amount of conversion of the fluorides by reaction with water. Films which show the presence ofmore » some unreacted barium fluoride have strong c-axis normal preferred orientation, with a sharp resistive transition. When all the barium fluoride is converted, the film is more randomly oriented and exhibits a broader transition to zero resistance.« less
  • Superconducting thin films of Ba{sub 2}YCu{sub 3}O{sub 7-{ital x}} were prepared on (100) SrTiO{sub 3} substrates by metalorganic deposition (MOD) of trifluoroacetate precursors. The best electrical transport properties were measured in films annealed at 750 {degree}C in a humid, low P{sub O{sub 2}} gas mixture followed by slow cooling in oxygen. These specimens had sharp resistive transitions with {ital T}{sub {ital c}} above 90 K and zero-field critical current densities in excess of 10{sup 6} A/cm{sup 2} at 77 K. Critical current densities of this magnitude have not previously been reported in films produced by MOD. The highest {ital J}{submore » {ital c}} obtained in films fired only in humid oxygen was 3{times}10{sup 5} A/cm{sup 2}. Annealing at high temperature in the low P{sub O{sub 2}} atmosphere also resulted in a smoother surface morphology than was observed in the oxygen-fired films. Use of the low P{sub O{sub 2}} furnace gas appeared to suppress the formation of {ital b}-axis normal oriented grains in the superconducting films and to strengthen {ital c}-axis normal texture. X-ray powder diffraction indicated the presence of {ital a}-axis normal textured material in the films, although it was not present as separate microstructural features which could be identified by scanning electron microscopy.« less