Photoluminescence spectra of thenardite Na2SO4 activated with rare-earth ions, Ce3+, Sm3+, Tb3+, Dy3+ and Tm3+

Chabazite-Ca deposited on dacite laccolith from Osódi Hill, Dunabogdány, Hungary, exhibited bluishwhite luminescence under ultraviolet (UV) light. The photoluminescence (PL) and optical excitation spectra of chabazite-Ca were obtained at 300 K. The PL spectrum under 300-nm excitation consists of (1) a Ce 3? band with a peak at 340 nm, (2) a broad main band with a peak at 453 nm and (3) five narrow bands at 592, 616, 650, 700 and 734 nm due to Eu 3? . The main band is spread over the entire visible-wavelength region. The excitation spectrum obtained by monitoring green luminescence at 520 nm consists of a band at wavelengths shorter than 200 nm and an extremely broad band with a peak at 385 nm. The extremely broad band is spread over not only the UV region but also the blue region. The features of PL and excitation spectra suggest that the origin of bluish-white luminescence is luminescent organic matter incorporated into chabazite-Ca crystals during growth.

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“…(Caldiño et al 1989), 335 and 356 nm in Na 2 SO 4 :Ce 3? (Aierken et al 2011) and 345 and 370 nm in CaCO 3 :Ce 3? (Chapoulie et al 1995).…”

Section: Discussionmentioning

confidence: 98%

Luminescence spectra of chabazite-Ca, a zeolite mineral

2012

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“…Mixed sulfates such as K 2 Ca 2 (SO 4 ) 3 and LiNaSO 4 have been of much interest to researchers [17][18][19][20]. Till to the date, only few works were reported on the luminescence studies of doped/codoped sodium sulfate [21][22][23]. Correcher et al observed the spectra of infraredstimulated luminescence (IRSL), radioluminescence (RL) and TL studies in the range of 200-800 nm on phase transitions of Na 2 SO 4 [24].…”

Section: Introductionmentioning

confidence: 99%

Influence of Li+ and Dy3+ on structural and thermoluminescence studies of sodium sulfate

Vidya

Lakshminarasappa

2014

Appl. Phys. A

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Na 2 SO 4 , Na 2 SO 4 : Dy 3? , LiNaSO 4 and LiNaSO 4 : Dy 3? nanoparticles successfully synthesized by slow evaporation technique followed by calcination at 400 o C. The resultant products were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared and UVVis spectroscopy. The average crystallite size was calculated using Debye-Scherrer's formula and WilliamsonHall's (W-H) plots. The optical energy band gap (E g ) was estimated from Wood and Tauc's relation, which varies from 3.70 to 4.45 eV. The variation in band gap values attributed to large degree of structural defects. Thermoluminescence studies were investigated using c-irradiation in the dose range 0.5-5 kGy at a heating rate of 5 K s -1 . The samples Na 2 SO 4 and LiNaSO 4 showed a well-resolved glow peak at *180 and *170°C, respectively. The prominent glow peak at *175°C along with shouldered peak at *60°C was observed for Na 2 SO 4 : Dy 3? . LiNaSO 4 : Dy 3? showed prominent glow peak at *100°C and a small shoulder peak at *180°C. The addition of isovalent (Li ? ) quenches the TL intensity, whereas the hypervalent (Dy 3? ) increases the intensity of Na 2 SO 4 . The variations of TL intensity for all the phosphors follow linear behavior up to 5 kGy and were useful in radiation dosimetry. The kinetic parameters (E, b and s) were estimated from the glow peak shape method.

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“…Correcher et al, (2004) observed the spectra of infrared -stimulated luminescence (IRSL), radioluminescence (RL) and TL of thenardite but failed to identify the origin of the luminescence center related to the IRSL, RL and TL spectra of thenardite. Sidike et al (2009) studied the PL excitation and decay curves of natural, heat -treated and γ-irradiated thenardite from Ai -Diang salt lake and concluded that crystal defects were responsible for observed luminescence. Reliable studies on the PL and TL properties of thenardite were very few to till date, to the best of our knowledge.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization and Thermoluminescence Studies of LiNaSO4: Eu3+ nanophosphor

Vidya¹,

Lakshminarasappa²

2014

JLA

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Na2SO4, LiNaSO4 and LiNaSO4: Eu 3+ nanophosphors were successfully synthesized by slow evaporation technique followed by calcination at 400° C. The resultant products were characterized by using powder Xray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), UV -Vis, scanning electron microscope (SEM) and transmission electron microscope (TEM). Doping with Li + ion stabilized the thenardite phase (Phase V) while, codoping with Eu 3+ promoted the phase transformation from stable thenardite to metastable mirabilite (Phase III) crystal structure. The average crystallite size was calculated by using Debye -Scherrer's formula and Williamson -Hall (W -H) plots. The optical energy band gap (Eg) of Na2SO4, LiNaSO4 and LiNaSO4: Eu 3+ were estimated from Wood and Tauc's relation which varies from 4.2 -4.33 eV. Thermoluminescence (TL) studies were investigated by using γ -irradiation in the dose range 0.5 -5 kGy at a heating rate of 5 °C s -1 . A well resolved glow peaks at ~ 180 °C, ~ 150 °C and ~115 °C were recorded for Na2SO4, LiNaSO4 and LiNaSO4: Eu 3+ nanophosphors respectively. It was observed that isovalent doping of Li + served as quencher, while codoping of hypervalent Eu 3+ acted as activator to enhance the TL intensity of glow peak. In the present study, the extent of TL fading of LiNaSO4: Eu 3+ was 31 % compared to LiNaSO4 (52 %) and Na2SO4 (59 %). So, LiNaSO4: Eu 3+ phosphor might also have potential use in dosimetry. The kinetic parameters namely activation energy (E), frequency factor (s) and order of kinetics (b) was estimated and the results were discussed.

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Photoluminescence spectra of thenardite Na2SO4 activated with rare-earth ions, Ce3+, Sm3+, Tb3+, Dy3+ and Tm3+

Cited by 13 publications

References 28 publications

Luminescence spectra of chabazite-Ca, a zeolite mineral

Luminescence spectra of chabazite-Ca, a zeolite mineral

Influence of Li+ and Dy3+ on structural and thermoluminescence studies of sodium sulfate

Synthesis, Characterization and Thermoluminescence Studies of LiNaSO4: Eu3+ nanophosphor

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