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Atomic scale verification of oxide-ion vacancy distribution near a single grain boundary in YSZ.

An J, Park JS, Koh AL, Lee HB, Jung HJ, Schoonman J, Sinclair R, Gür TM, Prinz FB - Sci Rep (2013)

Bottom Line: We show significant oxygen deficiency due to segregation of oxide-ion vacancies near the grain-boundary core with half-width < 0.6 nm.Oxide-ion density distribution near a grain boundary simulated by molecular dynamics corroborated well with experimental results.Such column-by-column quantification of defect concentration in functional materials can provide new insights that may lead to engineered grain boundaries designed for specific functionalities.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA [2].

ABSTRACT
This study presents atomic scale characterization of grain boundary defect structure in a functional oxide with implications for a wide range of electrochemical and electronic behavior. Indeed, grain boundary engineering can alter transport and kinetic properties by several orders of magnitude. Here we report experimental observation and determination of oxide-ion vacancy concentration near the Σ13 (510)/[001] symmetric tilt grain-boundary of YSZ bicrystal using aberration-corrected TEM operated under negative spherical aberration coefficient imaging condition. We show significant oxygen deficiency due to segregation of oxide-ion vacancies near the grain-boundary core with half-width < 0.6 nm. Electron energy loss spectroscopy measurements with scanning TEM indicated increased oxide-ion vacancy concentration at the grain boundary core. Oxide-ion density distribution near a grain boundary simulated by molecular dynamics corroborated well with experimental results. Such column-by-column quantification of defect concentration in functional materials can provide new insights that may lead to engineered grain boundaries designed for specific functionalities.

No MeSH data available.


Related in: MedlinePlus

(a) Normalized intensity (experimental) and normalized peak ion density (simulated) of cation columns (both normalized by average cation column ion density of 225). (b) Normalized intensity and normalized peak ion density of anion columns (both normalized by average anion column ion density of 175). (c) O/Zr intensity ratio plot and O/Zr ion density ratio plot. 6 columns were counted for each data point. The error bar size is 1-standard deviation.
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f4: (a) Normalized intensity (experimental) and normalized peak ion density (simulated) of cation columns (both normalized by average cation column ion density of 225). (b) Normalized intensity and normalized peak ion density of anion columns (both normalized by average anion column ion density of 175). (c) O/Zr intensity ratio plot and O/Zr ion density ratio plot. 6 columns were counted for each data point. The error bar size is 1-standard deviation.

Mentions: Ionic densities of individual columns are extracted from the simulation results, normalized by the average ion density of the > 1.5 nm region, and converted into 1-D ion density plots. The results are shown by the dotted-lines in Figures 4(a) (for cations) and 4(b) (for anions). Experimentally measured column intensities normalized by average intensity of > 1.5 nm in TEM image are shown in solid-lines in Figures 4(a) and 4(b). The trends in both sets show again that the cation and anion densities decrease in the vicinity of the center of the GB core (the first and second data points). This demonstrates qualitative agreement between the experimental results and computational predictions. A sharp drop in the oxide-ion density observed in Figure 4(b) corresponds to the segregation of the vacancies in the GB core region. The intensity ratio and the ionic density ratio between anion and cation columns are shown in Figure 4(c). The general trends in the experimental data and the computational results also agree with each other in this plot.


Atomic scale verification of oxide-ion vacancy distribution near a single grain boundary in YSZ.

An J, Park JS, Koh AL, Lee HB, Jung HJ, Schoonman J, Sinclair R, Gür TM, Prinz FB - Sci Rep (2013)

(a) Normalized intensity (experimental) and normalized peak ion density (simulated) of cation columns (both normalized by average cation column ion density of 225). (b) Normalized intensity and normalized peak ion density of anion columns (both normalized by average anion column ion density of 175). (c) O/Zr intensity ratio plot and O/Zr ion density ratio plot. 6 columns were counted for each data point. The error bar size is 1-standard deviation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3775093&req=5

f4: (a) Normalized intensity (experimental) and normalized peak ion density (simulated) of cation columns (both normalized by average cation column ion density of 225). (b) Normalized intensity and normalized peak ion density of anion columns (both normalized by average anion column ion density of 175). (c) O/Zr intensity ratio plot and O/Zr ion density ratio plot. 6 columns were counted for each data point. The error bar size is 1-standard deviation.
Mentions: Ionic densities of individual columns are extracted from the simulation results, normalized by the average ion density of the > 1.5 nm region, and converted into 1-D ion density plots. The results are shown by the dotted-lines in Figures 4(a) (for cations) and 4(b) (for anions). Experimentally measured column intensities normalized by average intensity of > 1.5 nm in TEM image are shown in solid-lines in Figures 4(a) and 4(b). The trends in both sets show again that the cation and anion densities decrease in the vicinity of the center of the GB core (the first and second data points). This demonstrates qualitative agreement between the experimental results and computational predictions. A sharp drop in the oxide-ion density observed in Figure 4(b) corresponds to the segregation of the vacancies in the GB core region. The intensity ratio and the ionic density ratio between anion and cation columns are shown in Figure 4(c). The general trends in the experimental data and the computational results also agree with each other in this plot.

Bottom Line: We show significant oxygen deficiency due to segregation of oxide-ion vacancies near the grain-boundary core with half-width < 0.6 nm.Oxide-ion density distribution near a grain boundary simulated by molecular dynamics corroborated well with experimental results.Such column-by-column quantification of defect concentration in functional materials can provide new insights that may lead to engineered grain boundaries designed for specific functionalities.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA [2].

ABSTRACT
This study presents atomic scale characterization of grain boundary defect structure in a functional oxide with implications for a wide range of electrochemical and electronic behavior. Indeed, grain boundary engineering can alter transport and kinetic properties by several orders of magnitude. Here we report experimental observation and determination of oxide-ion vacancy concentration near the Σ13 (510)/[001] symmetric tilt grain-boundary of YSZ bicrystal using aberration-corrected TEM operated under negative spherical aberration coefficient imaging condition. We show significant oxygen deficiency due to segregation of oxide-ion vacancies near the grain-boundary core with half-width < 0.6 nm. Electron energy loss spectroscopy measurements with scanning TEM indicated increased oxide-ion vacancy concentration at the grain boundary core. Oxide-ion density distribution near a grain boundary simulated by molecular dynamics corroborated well with experimental results. Such column-by-column quantification of defect concentration in functional materials can provide new insights that may lead to engineered grain boundaries designed for specific functionalities.

No MeSH data available.


Related in: MedlinePlus