F-centre luminescence in nanocrystalline CeO<sub>2</sub>

Aškrabić, Sonja; Dohčević‐Mitrović, Z.; Araújo, V. D.; Ioniţă, Gabriela; Lima, M. M. de; Cantarero, A.

doi:10.1088/0022-3727/46/49/495306

Cited by 76 publications

(54 citation statements)

References 51 publications

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“…According to the equation 17 where E D is a constant, the optical bandgap energy of the CeO 2 film is derived to be ∼3.62 eV, which is consistent with the experimentally and theoretically derived values reported previously. 9,[17][18][19] It should be noted that the optical bandgap energy of the 450 • C-annealed CeO 2 film is almost the same. The inset of Fig.…”

Section: Resultsmentioning

confidence: 93%

“…For CeO 2 , the optical gap between Ce 4f 0 band and O 2p valence band is ∼3.6 eV. 7,9 The oxygen vacancies with none, one and two trapped electrons introduce the ground and excited energy levels denoted as F ++ , F + , F 0 , F + * and F 0 * , respectively. While, the Ce 3+ ions induce a so-called Ce 4f 1 band lying above the O 2p valence band.…”

Section: Resultsmentioning

confidence: 99%

“…While, the Ce 3+ ions induce a so-called Ce 4f 1 band lying above the O 2p valence band. 9 In general, the oxygen vacancies tend to trap electrons and the Ce 3+ ions act as the hole traps. 15 At sufficiently high forward bias voltages, the holes accumulated nearby the CeO 2 /p + -Si interface are driven into Ce 4f 1 band.…”

Section: Resultsmentioning

confidence: 99%

“…[5][6][7] Recently, CeO 2 acting as a luminescent material has attracted considerable attention because of its low phonon cutoff energy, high optical transparency and facile formation of oxygen vacancies. [8][9][10] Morshed et al 11 and Choi et al 12 investigated photoluminescence (PL) from the CeO 2 films on silicon and they believed that the emission bands peaking at 400 and 358 nm were resulted from the newly formed phases of Ce 6 O 11 and Ce 2 Si 2 O 7 , respectively. Verma et al believed that the PL bands of the CeO 2 films centered at 425 and 486 nm, respectively, are relevant to the oxygen vacancies and the co-existing Ce 3+ ions further enhanced such PL.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, they proposed the energy levels of the aforementioned oxygen vacancies in the bandgap of CeO 2 . 9 In contrast with the diverse research efforts expended on the PL from CeO 2 , the realization of electroluminescence (EL) from CeO 2 -based devices has not been reported so far.…”

Section: Introductionmentioning

confidence: 99%

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Ultraviolet-visible electroluminescence from metal-oxide-semiconductor devices with CeO2 films on silicon

Zhu

Wang

et al. 2015

AIP Advances

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We report on ultraviolet-visible (UV-Vis) electroluminescence (EL) from metal-oxide-semiconductor (MOS) devices with the CeO2 films annealed at low temperatures. At the same injection current, the UV-Vis EL from the MOS device with the 550 °C-annealed CeO2 film is much stronger than that from the counterpart with the 450 °C-annealed CeO2 film. This is due to that the 550 °C-annealed CeO2 film contains more Ce3+ ions and oxygen vacancies. It is tentatively proposed that the recombination of the electrons in multiple oxygen-vacancy–related energy levels with the holes in Ce 4f1 energy band pertaining to Ce3+ ions leads to the UV-Vis EL.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ultraviolet-visible electroluminescence from metal-oxide-semiconductor devices with CeO2 films on silicon

Zhu

Wang

et al. 2015

AIP Advances

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Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions

Zheng

Mofarah

Cazorla

et al. 2021

Adv Funct Materials

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Critical catalysis studies often lack elucidation of the mechanistic role of defect equilibria in solid solubility and charge compensation. This approach is applied to interpret the physicochemical properties and catalytic performance of a free-standing 2D-3D CeO 2−x scaffold, which is comprised of holey 2D nanosheets, and its heterojunctions with MoO 3−x and RuO 2 . The band gap alignment and structural defects are engineered using density functional theory (DFT) simulations and atomic characterization. Further, the heterojunctions are used in hydrogen evolution reaction (HER) and catalytic ozonation applications, and the impacts of the metal oxide heteroatoms are analyzed. A key outcome is that the principal regulator of the ozonation performance is not oxygen vacancies but the concentration of Ce 3+ and Ce vacancies. Cation vacancy defects are measured to be as high as 8.1 at% for Ru-CeO 2−x . The homogeneous distribution of chemisorbed, Mo-oxide, heterojunction nanoparticles on the CeO 2−x holey nanosheets facilitates intervalence charge transfer, resulting in the dominant effect and resultant ≈50% decrease in overpotential for HER. The heterojunctions are tested for aqueous-catalytic ozonation of salicylic acid, revealing excellent catalytic performance from Mo doping despite the adverse impact of Ce vacancies. The present study highlights the use of defect engineering to leverage experimental and DFT results for band alignment.

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Tiered Electron Anions in Multiple Voids of LaScSi and Their Applications to Ammonia Synthesis

et al. 2017

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Electrides-compounds in which electrons localized in interstitial spaces periodically serve as anions-have attracted broad attention for their exotic properties, such as extraordinary electron-donating ability. In our efforts to expand this small family of phases, LaScSi emerges as a promising candidate. Its electron count is 2e f.u. in excess of that expected from the Zintl concept, while its structure offers interstitial spaces that can accommodate these extra electrons. Herein, this potential is explored through density functional theory (DFT) calculations and property measurements on LaScSi. DFT calculations (validated by heat capacity and electrical transport measurements) reveal electron density peaks at two symmetry-distinct interstitial sites. Importantly, this electride-like character is combined with chemical stability in air and water, an advantage for catalysis. Ru-loaded LaScSi shows outstanding catalytic activity for ammonia synthesis, with a turnover frequency (0.1 s at 0.1 MPa, 400 °C) an order of magnitude higher than those of oxide-based Ru catalysts, e.g., Ru/MgO. As with other electrides, LaScSi's ability to reversibly store hydrogen prevents the hydrogen poisoning of Ru surfaces. The better performance of LaScSi, however, hints at the importance of the high concentration (>1.6 × 10 cm ) and tiered nature of its anionic electrons, which offers guidance toward new catalysts.

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F-centre luminescence in nanocrystalline CeO₂

Cited by 76 publications

References 51 publications

Ultraviolet-visible electroluminescence from metal-oxide-semiconductor devices with CeO2 films on silicon

Ultraviolet-visible electroluminescence from metal-oxide-semiconductor devices with CeO2 films on silicon

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions

Tiered Electron Anions in Multiple Voids of LaScSi and Their Applications to Ammonia Synthesis

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F-centre luminescence in nanocrystalline CeO2

Cited by 76 publications

References 51 publications

Ultraviolet-visible electroluminescence from metal-oxide-semiconductor devices with CeO2 films on silicon

Ultraviolet-visible electroluminescence from metal-oxide-semiconductor devices with CeO2 films on silicon

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO2−x‐Based Heterojunctions

Tiered Electron Anions in Multiple Voids of LaScSi and Their Applications to Ammonia Synthesis

Contact Info

Product

Resources

About

F-centre luminescence in nanocrystalline CeO₂

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions