Eu3+ doped tellurite glass ceramics containing SrF2 nanocrystals: Preparation, structure and luminescence properties

Walas, Michalina; Lewandowski, Tomasz; Synak, Anna; Łapiński, Marcin; Sadowski, W.; Kościelska, Barbara

doi:10.1016/j.jallcom.2016.11.301

Cited by 38 publications

(19 citation statements)

References 38 publications

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“…SrF2@NC catalysts, the binding energy of Sr 3d5/2 is 134 eV, which agrees well with the Sr in SrF2 [38,39]. With SrF2@C calcined at 700 °C, binding energy of Sr 3d5/2 shifts to 134.5 eV.…”

Section: Of 14supporting

confidence: 70%

Selectivity Dependence of 1,1-Difluoro-1-Chloroethane Dehydrohalogenation on the Metal–Support Interaction over SrF2 Catalyst

Liu

Mardochee

et al. 2020

Catalysts

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SrF2 promotes the dehydrochlorination (DeHCl) of 1,1-difluoro-1-chloroethane, which is the key process for the manufacture of VDF (vinylidene fluoride), one of the most typical fluorinated monomers. However, the selectivity is low as dehydrofluorination (DeHF) to VCF (vinylidene chlorofluoride) competes with the formation of VDF. In this study, SrF2@C (SrF2 embedded in carbon) and SrF2@NC (N-doped carbon) catalysts were fabricated following calcination in N2 with SrC2O4, PVDF (poly vinylidene fluoride) and urea as the precursors. The catalysts were characterized by XRD, SEM, TEM, and XPS. The results show that both the calcination temperature and N-doping play an important role in the conversion of HCFC-142b and the selectivity to VDF and VCF. Calcination at elevated temperatures enhances the Sr-C interaction. For SrF2@C, improved interaction facilitates withdrawing electrons from Sr by the carbon support. By contrast, the strong interaction of Sr with N-doped carbon supply electrons from N species to Sr. The electron deficiency of Sr is favorable for the adsorption of F with higher electronegativity and consequently, DeHF reaction forming VCF. The supply of electrons to Sr by the support improves the formation of VDF (DeHCl). The present work provides a potential strategy for the improvement of selectivity to the target product.

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“…SrF2@NC catalysts, the binding energy of Sr 3d5/2 is 134 eV, which agrees well with the Sr in SrF2 [38,39]. With SrF2@C calcined at 700 °C, binding energy of Sr 3d5/2 shifts to 134.5 eV.…”

Section: Of 14supporting

confidence: 70%

Selectivity Dependence of 1,1-Difluoro-1-Chloroethane Dehydrohalogenation on the Metal–Support Interaction over SrF2 Catalyst

Liu

Mardochee

et al. 2020

Catalysts

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“…The significant decrease in the R/O ratio after the heat treatment of both samples is proof of efficient incorporation of Eu 3+ ions in the SrF2 crystalline phase. As discussed in [3,[10][11][12][44][45][46][47] the electric dipole transition 5 D0 → 7 F2 becomes forbidden in centrosymmetric environment and thus in high symmetry crystal fields Eu 3+ luminescence is shifted to orange spectral region. In agreement with the XRD data, the decreased value of initial R/O ratio also suggests the increased crystallinity of the S2_PG sample.…”

Section: Pl Studiesmentioning

confidence: 91%

“…Previous photoluminescence studies have shown that in tellurite GC the initial trivalent Europium enters SrF2 crystallites in the 3+ state [10], whereas in oxyfluoride GC heat treatment and precipitation of SrF2 leads to reduction of europium ions to the 2+ state [20]. Sample preparation in reducing atmosphere can lead to abundance of Eu 2+ in the precursor glass resulting in broad blue emission, which is further intensified after crystallization of SrF2 particles in the matrix.…”

Section: Gcsmentioning

confidence: 99%

“…The intensity ratio of electric dipole ( 5 D0 → 7 F2) and magnetic dipole ( 5 D0 → 7 F1) allowed transitions also called as Red/Orange (R/O) ratio, on the other hand, strongly depends on the local site symmetry, thus, Eu 3+ ions may be used as optical probes to study the local structure around luminescence centres. [9] Shift of R/O ratio has been observed in GCs after annealing the precursor glasses when Eu 3+ enters BaCl2 [3], SrF2 [10], LaF3 [11], NaLuF4 [12] and other crystalline phases.…”

Section: Introductionmentioning

confidence: 99%

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Electron paramagnetic resonance and photoluminescence investigation of europium local structure in oxyfluoride glass ceramics containing SrF2 nanocrystals

et al. 2017

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Different compositions of europium doped aluminosilicate oxyfluoride glass ceramics prepared in air atmosphere have been studied by electron paramagnetic resonance (EPR) and optical spectroscopy methods. X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements show presence of homogenously distributed SrF2 nanocrystals after the heat treatment of the precursor glass. Efficient Eu 3+ incorporation in the high symmetry environment of glass ceramics is observed from the photoluminescence spectra. EPR spectra indicate Eu 3+ → Eu 2+ reduction upon precipitation of crystalline phases in the glass matrix. For composition abundant with Eu 2+ in the glassy state such behaviour is not detected. Local structure around europium ions is discussed based on differences in chemical compositions.

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“…In recent years, wide attention has been focused on the study of glasses containing both tellurium oxide and heavy metal fluorides [1,2] they combine the high resistance against atmospheric moisture, the chemical durability and the mechanical strength of the tellurite glasses [3] in addition to the large electronic band gap and the low optical losses of fluoride glasses [4][5][6][7][8][9] that makes them useful for a development of high power laser materials such as solid-state lasers and optical amplifiers upon doping with rare earth ions [10].…”

Section: Introductionmentioning

confidence: 99%

Coupling between surface plasmon resonance and Sm3+ ions induced enhancement of luminescence properties in fluoro-tellurite glasses

Mechergui¹,

Fares

Mohamed

et al. 2017

Journal of Luminescence

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Fluoro-tellurite glasses co-activated with Samarium (Sm 3+) ions and silver nanoparticles (Ag NPs) were prepared using melt quenching technique. The nucleation and growth of Ag NPs were controlled by thermal annealing process. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), UV-vis-NIR absorption spectroscopy, photoluminescence (PL) and PL lifetime spectroscopy were used to examine the annealing time dependence of the structural and luminescent properties. The amorphous nature of glasses has been confirmed by XRD spectra. The transmission electron microscopy images show the presence of silver NPs having an average diameter in the range of 20-40 nm. Selected area electron diffraction pattern (SAED), as well as EDX analysis spectrum confirm the presence of Ag NPs. Based on the absorption results, the intensity parameters Ω t (t=2, 4, 6), the radiative transition probability (A T), fluorescence branching ratio (β JJ') and radiative lifetimes (τ r) of Sm 3+ ions were calculated using Judd-Ofelt theory. The results suggest that Sm 3+ ions have been incorporated into Ag NPs, which intensified the electromagnetic field around Sm 3+ ions. The luminescence properties of Sm 3+ doped glasses were investigated. It was found that the presence of silver NPs nucleated and growth during the annealing process, improves the photoluminescence (PL) intensity and the PL lifetime relative to the transition from the 4 G 5/2 state to 6 H 5/2 , 6 H 7/2 , 6 H 9/2 and 6 H 11/2 states. Maximum enhancement is observed for the sample heat treated for 8 h. Such enhancement is mainly attributed to the local electric field created by the SPR of Ag NPs. whereas; the quenching is due to the energy transfer from Sm 3+ ions to the silver nanoparticles as well as to the non-plasmonic, molecule likes Ag-particles (ML-Ag). The present results indicate that the glass heat-treated for 8 h has good prospect for Laser emissions at 600 nm.

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Eu3+ doped tellurite glass ceramics containing SrF2 nanocrystals: Preparation, structure and luminescence properties

Cited by 38 publications

References 38 publications

Selectivity Dependence of 1,1-Difluoro-1-Chloroethane Dehydrohalogenation on the Metal–Support Interaction over SrF2 Catalyst

Selectivity Dependence of 1,1-Difluoro-1-Chloroethane Dehydrohalogenation on the Metal–Support Interaction over SrF2 Catalyst

Electron paramagnetic resonance and photoluminescence investigation of europium local structure in oxyfluoride glass ceramics containing SrF2 nanocrystals

Coupling between surface plasmon resonance and Sm3+ ions induced enhancement of luminescence properties in fluoro-tellurite glasses

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