ESR and luminescent properties of anion-deficient α-Al2O3 single crystals after high-dose irradiation by a pulsed electron beam

Ananchenko, D.V.; Nikiforov, S. V.; Konev, S. F.; Ramazanova, G. R.

doi:10.1016/j.optmat.2019.02.013

Cited by 10 publications

(5 citation statements)

References 25 publications

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“…On the other hand, in electron paramagnetic resonance (EPR) spectroscopy, the defective meso‐Al 2 O 3 shows a remarkable symmetric absorption peak (Figure 2c) at around 326.7 mT. The g‐factor of the EPR absorption line was calculated to be 2.011, indexing to electrons captured by oxygen vacancies [19] . In X‐ray photoelectron spectroscopy (XPS) curves (Figure S5), the Al 2p peak of meso‐Al 2 O 3 shifts from 74.3 eV to 74.7 eV, further suggesting the presence of oxygen vacancies in defective meso‐Al 2 O 3 .…”

Section: Resultsmentioning

confidence: 99%

Solar‐Driven Overproduction of Biofuels in Microorganisms

et al. 2022

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Microbial cell factories reinvigorate current industries by producing complex fine chemicals at low costs. Reduced nicotinamide adenine dinucleotide phosphate (NADPH) is the main reducing power to drive the biosynthetic pathways in microorganisms. However, insufficient intrinsic NADPH limits the productivity of microorganisms. Here, we report that supplying microorganisms with long-lived electrons from persistent phosphor mesoporous Al 2 O 3 (meso-Al 2 O 3 ) can elevate the NADPH level to facilitate efficient fine chemical production. The defects in meso-Al 2 O 3 were demonstrated to be highly efficient in prolonging electrons' lifetime. The long-lived electrons in meso-Al 2 O 3 can pass the material-microorganism interface and power the biosynthetic pathways of E. coli to produce jet fuel farnesene. This work represents a reliable strategy to design photo-biosynthesis systems to improve the productivity of microorganisms with solar energy.

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Section: Resultsmentioning

confidence: 99%

Solar‐Driven Overproduction of Biofuels in Microorganisms

et al. 2022

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“…[ 18,19 ] In the last few decades, many proven efforts have been spent to study the optical properties and structural defect inhomogeneities caused by both the growth procedure and the radiation‐induced point and extended defects in Gd 3 Ga 5 O 12 single crystals. [ 3,5,14,20–27 ] It should be noted here that, in contrast to well‐studied oxide materials, such as MgO, CaO, Al 2 O 3 , MgAl 2 O 4 , etc., [ 28–45 ] the existing understanding of the nature of radiation defects and appropriate radiation‐induced processes in Gd 3 Ga 5 O 12 is still insufficient.…”

Section: Introductionmentioning

confidence: 99%

“…[18,19] In the last few decades, many proven efforts have been spent to study the optical properties and structural defect inhomogeneities caused by both the growth procedure and the radiation-induced point and extended defects in Gd 3 Ga 5 O 12 single crystals. [3,5,14,[20][21][22][23][24][25][26][27] It should be noted here that, in contrast to well-studied oxide materials, such as MgO, CaO, Al 2 O 3 , MgAl 2 O 4 , etc., [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] the existing understanding of the nature of radiation defects and appropriate radiation-induced processes in Gd 3 Ga 5 O 12 is still insufficient. This is mainly due to the lack of experimental data, which, in turn, is associated with the low efficiency of point defect formation in Gd 3 Ga 5 O 12 single crystals.…”

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confidence: 99%

Optical, Structural, and Mechanical Properties of Gd₃Ga₅O₁₂ Single Crystals Irradiated with ⁸⁴Kr⁺ Ions

Karipbayev

Kumarbekov

Manika

et al. 2022

Physica Status Solidi (b)

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Herein, the optical absorption, X‐ray diffraction (XRD) analysis data, and mechanical properties along the ion path are analyzed for gadolinium gallium garnet (Gd3Ga5O12 or GGG) single crystals irradiated with fast 84Kr ions to fluences of 1013–1014 ion cm−2. It is found that the optical absorption spectra of Czochralski‐grown unirradiated GGG crystal consist of relatively narrow lines in the UV spectral range associated with the 4f–4f transitions in Gd3+ ions. Transitions from the 6S7/2 ground state to the 6P, 6J, and 6D states in the Gd3+ cation are visible. An additional absorption band is also observed at 350 nm, which is associated with an uncontrolled Ca impurity. In irradiated GGG single crystals, a shift of the fundamental absorption edge by ≈30 nm to the long‐wavelength part of the spectrum is observed. The observed changes are caused by structural disturbances caused by depletion of the surface layer and an increase in the number of displaced atoms accompanied by an increase in the crystal lattice parameter. XRD analysis shows the presence of size effects and deformation of interplanar distances due to the displacement of atoms from the sites of the crystal lattice with subsequent migration. Hardness measurements show ion‐induced softening, which may be due to ion‐induced amorphization.

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“…An ordinary F-center consists of one electron captured by a halogen vacancy [1,2,5]. Such F (Farbe) centers in alkali halides and alkaline-earth halides and oxides have been studied for many decades [1,2,[5][6][7][8][9][10][11][12]. Thus, F-centers are defects in ionic crystals in which an anion is replaced by one or more trapped electrons.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, F-centers are defects in ionic crystals in which an anion is replaced by one or more trapped electrons. These vacancy-trapped electrons, confined and screened by the surrounding crystal lattice, thus form gap states with unique optical, electrical and magnetic properties [7][8][9][10][11][12][13][14][15][16] that are relevant to different optoelectronic devices. How efficient the formation is of point defects, including F-centers, is also the determining factor of the material radiation resistance in nuclear applications [17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Tendencies in ABO3 Perovskite and SrF2, BaF2 and CaF2 Bulk and Surface F-Center Ab Initio Computations at High Symmetry Cubic Structure

et al. 2021

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We computed the atomic shift sizes of the closest adjacent atoms adjoining the (001) surface F-center at ABO3 perovskites. They are significantly larger than the atomic shift sizes of the closest adjacent atoms adjoining the bulk F-center. In the ABO3 perovskite matrixes, the electron charge is significantly stronger confined in the interior of the bulk oxygen vacancy than in the interior of the (001) surface oxygen vacancy. The formation energy of the oxygen vacancy on the (001) surface is smaller than in the bulk. This microscopic energy distinction stimulates the oxygen vacancy segregation from the perovskite bulk to their (001) surfaces. The (001) surface F-center created defect level is nearer to the (001) surface conduction band (CB) bottom as the bulk F-center created defect level. On the contrary, the SrF2, BaF2 and CaF2 bulk and surface F-center charge is almost perfectly confined to the interior of the fluorine vacancy. The shift sizes of atoms adjoining the bulk and surface F-centers in SrF2, CaF2 and BaF2 matrixes are microscopic as compared to the case of ABO3 perovskites.

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ESR and luminescent properties of anion-deficient α-Al2O3 single crystals after high-dose irradiation by a pulsed electron beam

Cited by 10 publications

References 25 publications

Solar‐Driven Overproduction of Biofuels in Microorganisms

Solar‐Driven Overproduction of Biofuels in Microorganisms

Optical, Structural, and Mechanical Properties of Gd₃Ga₅O₁₂ Single Crystals Irradiated with ⁸⁴Kr⁺ Ions

Tendencies in ABO3 Perovskite and SrF2, BaF2 and CaF2 Bulk and Surface F-Center Ab Initio Computations at High Symmetry Cubic Structure

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ESR and luminescent properties of anion-deficient α-Al2O3 single crystals after high-dose irradiation by a pulsed electron beam

Cited by 10 publications

References 25 publications

Solar‐Driven Overproduction of Biofuels in Microorganisms

Solar‐Driven Overproduction of Biofuels in Microorganisms

Optical, Structural, and Mechanical Properties of Gd3Ga5O12 Single Crystals Irradiated with 84Kr+ Ions

Tendencies in ABO3 Perovskite and SrF2, BaF2 and CaF2 Bulk and Surface F-Center Ab Initio Computations at High Symmetry Cubic Structure

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Optical, Structural, and Mechanical Properties of Gd₃Ga₅O₁₂ Single Crystals Irradiated with ⁸⁴Kr⁺ Ions