Phonon confinement effect on nanocrystalline LiCoO2 studied with Raman spectroscopy

M. Okubo; E. Hosono; T. Kudo; H. S. Zhou; I. Honma

doi:10.1016/j.jpcs.2008.08.009

Phonon confinement effect on nanocrystalline LiCoO₂ studied with Raman spectroscopy

M. Okubo, E. Hosono, T. Kudo, H. S. Zhou, I. Honma^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

12 Citations (Scopus)

Abstract

A systematic investigation on nanocrystalline LiCoO₂ has been carried out using Raman spectroscopy. We synthesized nanocrystalline LiCoO ₂ (ca. 20-50nm) through a combination of rapid thermal annealing at various annealing temperatures and a sol-gel method assisted with a triblock copolymer surfactant. Powder X-ray diffraction measurements revealed the formation of LiCoO₂. The crystallite size of LiCoO₂ from the Scherrer equation strongly depended on the annealing temperature. The crystallite size was confirmed by SEM and TEM measurements. Raman shifts of the A_1g and E_g modes for nanocrystalline LiCoO₂ exhibited a broadening and a frequency shift according to the crystallite size. While the frequency shift could be ascribed to a structural strain at the surface, the broadening was due to the phonon confinement effect produced by narrow crystal boundaries.

Original language	English
Pages (from-to)	2911-2915
Number of pages	5
Journal	Journal of Physics and Chemistry of Solids
Volume	69
Issue number	11
DOIs	https://doi.org/10.1016/j.jpcs.2008.08.009
Publication status	Published - 2008 Nov
Externally published	Yes

Keywords

Ceramics
Phonoms
Raman spectroscopy

ASJC Scopus subject areas

Chemistry(all)
Materials Science(all)
Condensed Matter Physics

Access to Document

10.1016/j.jpcs.2008.08.009

Cite this

@article{115c23ee2c48447194c795118255165c,

title = "Phonon confinement effect on nanocrystalline LiCoO2 studied with Raman spectroscopy",

abstract = "A systematic investigation on nanocrystalline LiCoO2 has been carried out using Raman spectroscopy. We synthesized nanocrystalline LiCoO 2 (ca. 20-50nm) through a combination of rapid thermal annealing at various annealing temperatures and a sol-gel method assisted with a triblock copolymer surfactant. Powder X-ray diffraction measurements revealed the formation of LiCoO2. The crystallite size of LiCoO2 from the Scherrer equation strongly depended on the annealing temperature. The crystallite size was confirmed by SEM and TEM measurements. Raman shifts of the A1g and Eg modes for nanocrystalline LiCoO2 exhibited a broadening and a frequency shift according to the crystallite size. While the frequency shift could be ascribed to a structural strain at the surface, the broadening was due to the phonon confinement effect produced by narrow crystal boundaries.",

keywords = "Ceramics, Phonoms, Raman spectroscopy",

author = "M. Okubo and E. Hosono and T. Kudo and Zhou, {H. S.} and I. Honma",

note = "Funding Information: This work was supported by the New Energy and Industrial Technology Development Organization Japan, under a grant for Research and Development of Nanodevices for Practical Utilization of Nanotechnology (Nanotech Challenge Project).",

year = "2008",

month = nov,

doi = "10.1016/j.jpcs.2008.08.009",

language = "English",

volume = "69",

pages = "2911--2915",

journal = "Journal of Physics and Chemistry of Solids",

issn = "0022-3697",

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TY - JOUR

T1 - Phonon confinement effect on nanocrystalline LiCoO2 studied with Raman spectroscopy

AU - Okubo, M.

AU - Hosono, E.

AU - Kudo, T.

AU - Zhou, H. S.

AU - Honma, I.

N1 - Funding Information: This work was supported by the New Energy and Industrial Technology Development Organization Japan, under a grant for Research and Development of Nanodevices for Practical Utilization of Nanotechnology (Nanotech Challenge Project).

PY - 2008/11

Y1 - 2008/11

N2 - A systematic investigation on nanocrystalline LiCoO2 has been carried out using Raman spectroscopy. We synthesized nanocrystalline LiCoO 2 (ca. 20-50nm) through a combination of rapid thermal annealing at various annealing temperatures and a sol-gel method assisted with a triblock copolymer surfactant. Powder X-ray diffraction measurements revealed the formation of LiCoO2. The crystallite size of LiCoO2 from the Scherrer equation strongly depended on the annealing temperature. The crystallite size was confirmed by SEM and TEM measurements. Raman shifts of the A1g and Eg modes for nanocrystalline LiCoO2 exhibited a broadening and a frequency shift according to the crystallite size. While the frequency shift could be ascribed to a structural strain at the surface, the broadening was due to the phonon confinement effect produced by narrow crystal boundaries.

AB - A systematic investigation on nanocrystalline LiCoO2 has been carried out using Raman spectroscopy. We synthesized nanocrystalline LiCoO 2 (ca. 20-50nm) through a combination of rapid thermal annealing at various annealing temperatures and a sol-gel method assisted with a triblock copolymer surfactant. Powder X-ray diffraction measurements revealed the formation of LiCoO2. The crystallite size of LiCoO2 from the Scherrer equation strongly depended on the annealing temperature. The crystallite size was confirmed by SEM and TEM measurements. Raman shifts of the A1g and Eg modes for nanocrystalline LiCoO2 exhibited a broadening and a frequency shift according to the crystallite size. While the frequency shift could be ascribed to a structural strain at the surface, the broadening was due to the phonon confinement effect produced by narrow crystal boundaries.

KW - Ceramics

KW - Phonoms

KW - Raman spectroscopy

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