Effect of crystal structure and dopant concentration on the luminescence of Cr3+ in Al2O3 nanocrystals

Patra, Amitava; Tallman, R. E.; Weinstein, B. A.

doi:10.1016/j.optmat.2004.10.002

Cited by 53 publications

(24 citation statements)

References 22 publications

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“…This means that the signal at g eff Z1.98 is characteristic for both q-and a-(Al,Cr) 2 O 3 . The correlation of the Cr-pairs (or clusters) formation in a-(Al,Cr) 2 O 3 and the dominant EPR feature in the vicinity of g ff Z1.98 is confirmed [28]. Table 2.…”

Section: Epr Spectroscopymentioning

confidence: 63%

Structural studies of Cr-doped mullite derived from single-phase precursors

Tkalčeć

Gržeta

Popović

et al. 2006

Journal of Physics and Chemistry of Solids

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Section: Epr Spectroscopymentioning

confidence: 63%

Structural studies of Cr-doped mullite derived from single-phase precursors

Tkalčeć

Gržeta

Popović

et al. 2006

Journal of Physics and Chemistry of Solids

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“…The lines vanish when the crystalline structure is damaged [22]. Their spectral position depends on Cr 3+ concentration and red shifts with its increase [21].…”

Section: Resultsmentioning

confidence: 96%

“…The spectral position of these lines sensitively depends on the environment. In particular, when the Al 2 O 3 crystalline structure changes the doublet exhibits a shift [18,[20][21][22]. The lines vanish when the crystalline structure is damaged [22].…”

Section: Resultsmentioning

confidence: 98%

Synthesis and photoluminescence properties of nanostructured mullite/α-Al2O3

et al. 2014

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Phase transformation of a-Al 2 O 3 to mullite was observed by correlated X-ray diffraction and low-temperature (7 K) time-and energyresolved photoluminescence methods. The aluminosilicate solids with different Si:Al ratios were prepared after thermal treatment (1400°C) of ultraporous alumina (UPA) monoliths impregnated with vapour of silica precursors at room temperature. The initial dispersion of Si is homogeneous on a size-scale of 5 nm raw UPA fibres, which grow in size during the thermal treatment stage up to $50-100 nm. Three phases were resolved in the considered SiO 2 /Al 2 O 3 system: silica, a-Al 2 O 3 and their interaction product 2:1 mullite (2Al 2 O 3 :SiO 2 ). The 2:1 mullite mass increases and a-Al 2 O 3 mass decreases with an increase of the initial silica content. At the SiO 2 content in the initial system above 20 mol.%, the phase transformation to 2:1 mullite is complete and no a-Al 2 O 3 was observed. No mullite phases with either lower or higher Si content were observed. The fundamental absorption onset energy 7.55 eV of 2:1 mullite was measured.

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“…band appears sometimes in doublet, for example, at 692.9 nm (R 2 -line) and 694. 3 nm (R 1 -line) [35]. The Cr 3?…”

Section: Discussionmentioning

confidence: 98%

Triboplasma Generation and Triboluminescence: Influence of Stationary Sliding Partner

Nakayama

2009

Tribol Lett

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In this work, the characteristics of triboplasma have been investigated from the point of view of how the kinds of the stationary partner influence the photon energy and the plasma distribution. The energy spectrum and twodimensional images of the emitted photons were measured during the sliding of a diamond pin with a tip radius of 1.5 and 3 mm on the three kinds of disk made of Al 2 O 3 , MgO, and SiO 2 in dry sliding in air. The results showed that all the three kinds of solid tested had narrow bands of airdischarge plasma in the ultraviolet region, demonstrating that the triboplasma generation does not depend on the kinds of insulating solids. Triboplasma was distributed having a ring with one or two tails in all the three kinds of solid Al 2 O 3 , MgO, and SiO 2 . The mechanisms of UV, visible, and IR photon emissions are discussed. The UV photons are emitted from the ionized plasma gas produced by discharging of air, while the visible photons are emitted from the defect and impurity centers excited by the triboplasma-photons, triboplasma-electrons, and frictional temperature rise together with the photons from the plasma itself. A 696-nm narrow band appeared only with Al 2 O 3 , and it was attributed to the Cr 3? ions excited by the UV photons and electrons from the triboplasma. The IR photons should be emitted from the sliding contact by the thermal emissions consisting of thermoluminescence and blackbody radiation, as well as from the triboplasma. The visible photon emission was strongest at the pair points facing across the frictional track in Al 2 O 3 and MgO. To explain the photon emission at the pair points, a new model has been proposed, in which the visible photons are emitted from the surface defect and/or impurity centers excited by the back electrons accelerated with the inverse electric field caused by the negatively charged patches produced by the electron bombardment to the diamond surface. The negative charges on the frictional track repelled the back electrons, so that the back-electrons attack just outside the frictional track.

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Effect of crystal structure and dopant concentration on the luminescence of Cr3+ in Al2O3 nanocrystals

Cited by 53 publications

References 22 publications

Structural studies of Cr-doped mullite derived from single-phase precursors

Structural studies of Cr-doped mullite derived from single-phase precursors

Synthesis and photoluminescence properties of nanostructured mullite/α-Al2O3

Triboplasma Generation and Triboluminescence: Influence of Stationary Sliding Partner

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