Fano׳s antiresonance and crystal-field study of Cr3+ in metaphosphate glasses

Taktak, Olfa; Souissi, Hajer; Maalej, Olfa; Boulard, B.; Kammoun, S.

doi:10.1016/j.jlumin.2016.08.034

Cited by 21 publications

(8 citation statements)

References 42 publications

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“…The strongly oscillating conductance spectra are originated from the interference between the reflected wave from Fano defects and that propagating along the nanoribbon. Such Fano resonant and antiresonant spectra have been observed in optical, [ 30 ] plasmonic, [ 31 ] and transport [ 32 ] experiments.…”

Section: Discussionmentioning

confidence: 81%

Independent Channel Method for Nanoribbons with Dislocation and Fano Defects

Sánchez

Wang

2021

Physica Status Solidi (b)

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In 2D materials, the dislocation is a common structural defect at finite temperatures as its appearance reduces the free energy by rising entropy, whereas many clusters of atoms or molecules, called as Fano defects, can be adsorbed on their extensive surface. Herein, the electronic transport in a long square nanoribbon with planar dislocation and Fano defects is studied within the tight‐binding formalism including nearest‐ and next‐nearest‐neighbor hopping integrals. To this purpose, a new convolution method is developed to transform the nanoribbon into a set of independent channels, where a real‐space renormalization procedure is applied. Despite the almost unaltered densities of states, the ballistic transport of periodic nanoribbons is mostly destroyed by the introduction of such structural defects, except for several energies in the case of Fano defects, and dissimilar conductance spectra are found in these two analyzed cases.

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Section: Discussionmentioning

confidence: 81%

Independent Channel Method for Nanoribbons with Dislocation and Fano Defects

Sánchez

Wang

2021

Physica Status Solidi (b)

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“…Each 4 A 2 → 4 T 2 excitation band has a dip structure at approximately 700 nm owing to the Fano antiresonance phenomenon. 41) Although the peak wavelengths of excitation bands did not change with Cr concentration, the FWHMs tended to increase with increasing Cr concentration. Similar trends in the dependence of the shifting PL peak and broadening of the PLE bandwidth on the luminescent center concentration have often been reported for phosphor materials with multiple luminescent sites.…”

Section: Pl Propertiesmentioning

confidence: 89%

Broadband NIR luminescence of Cr³⁺-doped Mg₄Nb₂O₉ phosphors toward LED light source applications for NIR spectrometry

Nanai,

Satake,

Kitazawa

2024

Jpn. J. Appl. Phys.

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Herein, we report the photoluminescence (PL) properties of Cr3+-doped Mg4Nb2O9 phosphors for applications in NIR phosphor-converted LEDs. Trigonal Mg4Nb2O9 crystals with Cr3+ substitution at three sites were synthesized as the main phase using a solid-state reaction. X-ray photoelectron spectrometry and diffuse reflectance spectroscopy indicated that only trivalent chromium ions were present in the samples. Broadband NIR emission of Cr3+ suitable for combination with Si photodetectors was confirmed at approximately 850 nm. The maximum PL quantum yield (PLQY) was 0.62, and concentration quenching explained the Cr concentration dependence of the PLQY and PL decay time. Low-temperature PL measurements suggested that the PL spectrum comprised three distinct emission bands. The results of the phonon line simulation, low-temperature photoluminescence excitation measurements, and crystal-field parameter estimation clarified the correlation between these emission bands and the Cr3+ substitution sites.

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“…The 4 A 2 → 4 T 2 excitation band has the dip structure at 688 nm caused by Fano antiresonance due to the interaction between intra-t 2 3 levels ( 2 E and 2 T 1 ) and t e 2 level ( 4 T 2 ). 42) The Cr 4+ and Cr 6+ absorption bands were not recognized in the PLE spectra. Thus, the energy transfer from these chromium ions to Cr 3+ does not occur.…”

Section: Optical and Pl Propertiesmentioning

confidence: 97%

Synthesis and luminescence properties of Cr₂O₃-CaO-GeO₂ glass and glass ceramics for broadband NIR-LEDs

Nanai

Satake

Kitazawa

2023

Jpn. J. Appl. Phys.

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We report the fabrication of novel 0.1Cr2O3-25CaO-75GeO2 glass and glass ceramics with wideband NIR luminescence and the annealing temperature dependence of the photoluminescence (PL) properties for applications as NIR phosphors. The anisotropic growth of Ca2Ge7O16 nanocrystals in the annealing samples was confirmed. Annealing-induced variations in the body colors and diffuse reflectance spectra suggest that change in the valence of Cr ions and their coordination environments. Broadband luminescence of 700-1300 nm attributed to the 4T2 → 4A2 transition of Cr3+ was observed for the as-made glass. The peak wavelength is shifted from 860 to 780 nm, and line-shaped 2E → 4A2 emission appears due to the crystallization of Ca2Ge7O16 by heat treatment. The PL quantum efficiency reaches the maximum at 0.19 when the sample is annealed at 775ºC, and the dependence on annealing temperature can be understood by the change in the PL lifetimes and diffuse reflectance spectra.

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Fano׳s antiresonance and crystal-field study of Cr3+ in metaphosphate glasses

Cited by 21 publications

References 42 publications

Independent Channel Method for Nanoribbons with Dislocation and Fano Defects

Independent Channel Method for Nanoribbons with Dislocation and Fano Defects

Broadband NIR luminescence of Cr³⁺-doped Mg₄Nb₂O₉ phosphors toward LED light source applications for NIR spectrometry

Synthesis and luminescence properties of Cr₂O₃-CaO-GeO₂ glass and glass ceramics for broadband NIR-LEDs

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Fano׳s antiresonance and crystal-field study of Cr3+ in metaphosphate glasses

Cited by 21 publications

References 42 publications

Independent Channel Method for Nanoribbons with Dislocation and Fano Defects

Independent Channel Method for Nanoribbons with Dislocation and Fano Defects

Broadband NIR luminescence of Cr3+-doped Mg4Nb2O9 phosphors toward LED light source applications for NIR spectrometry

Synthesis and luminescence properties of Cr2O3-CaO-GeO2 glass and glass ceramics for broadband NIR-LEDs

Contact Info

Product

Resources

About

Broadband NIR luminescence of Cr³⁺-doped Mg₄Nb₂O₉ phosphors toward LED light source applications for NIR spectrometry

Synthesis and luminescence properties of Cr₂O₃-CaO-GeO₂ glass and glass ceramics for broadband NIR-LEDs