Luminescence depolarization mechanisms for color centers with the luminescence peak at 670 nm in gamma-irradiated LiF:Mg crystals

Иванов, Н. А.; Penzina, E. E.; Zilov, S. A.

doi:10.1134/1.1446583

Cited by 3 publications

(3 citation statements)

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“…Similar studies on Yb 2 + have been conducted by Xie et al [34]. The 548 nm emission in our case arises from excited levels of Yb 2 + ion as reported earlier [25,35]. The lifetime of levels responsible for the 442 and 548 nm bands are measured to be 230 and 270 ms at 20 K temperature indicating their distinctly different origins.…”

Section: Down Conversion Fluorescence Studiessupporting

confidence: 66%

“…The resulting color center may be responsible for the broad emission seen in the upconversion. Such emission from color centers has been reported in many materials by several workers [19,20,[25][26][27][28][29][30]. The dependence of the intensities on the calcination temperature is different for the 488 and the 508 nm bands (inset of Fig.…”

Section: Upconversion Luminescence Studiesmentioning

confidence: 89%

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Up and down conversion fluorescence studies on combustion synthesized Yb3+/Yb2+: MO-Al2O3 (M=Ca, Sr and Ba) phosphors

Verma

Rai²,

Kumar

et al. 2010

Journal of Luminescence

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Section: Down Conversion Fluorescence Studiessupporting

confidence: 66%

Section: Upconversion Luminescence Studiesmentioning

confidence: 89%

Up and down conversion fluorescence studies on combustion synthesized Yb3+/Yb2+: MO-Al2O3 (M=Ca, Sr and Ba) phosphors

Verma

Rai²,

Kumar

et al. 2010

Journal of Luminescence

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“…More defects are induced and can become luminescent centers. The defect-center-induced emission has been reported in various conventional materials. ,− For example, Rai and colleagues observed a blue-green emission band contributed by the defect centers due to the valence changes from trivalence to bivalence for ytterbium . Simultaneously, with the increase of Ca 2+ -ion doping concentration, the intensity of the IB emission increases first and then decreases, as shown in Figure S4.…”

Section: Resultsmentioning

confidence: 78%

Giant Enhancement in Upconversion Luminescence of β-Ba₂ScAlO₅:Yb³⁺/Er³⁺ Phosphor by the Intermediate Band through Ca²⁺ Doping

Bian

Wang

et al. 2022

Chem. Mater.

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Luminescence intensity is a critical issue for upconversion oxides with high phonon energy. Herein, an effective enhancement in red upconversion luminescence (UCL) is implemented via an intermediate band (IB) in the Ba2ScAlO5:Yb3+/Er3+ phosphor after Ca2+ doping. The downshifting luminescence spectra under the irradiation of a 320 nm laser verify the existence of the IB. The physical mechanism is that the valence band (VB) → IB transition increases the absorption of the excitation energy and provides plentiful electrons from the host to Er3+. Therefore, the red and green emission intensities are increased by 45.2 and 7.5 times, respectively. The dependence of luminescent intensity on power and an effective fluorescence lifetime of Ca2+-doped Ba2ScAlO5:Yb3+/Er3 also confirm the proposed energy transfer mechanism. Based on the excellent red emission, the temperature-dependent luminescent properties of the title material are explored in the temperature range from 298 to 358 K. The linear relationship between the luminescence and the temperature and the high sensitivity suggest the promising potential in biomedical temperature-sensing applications. This work paves a new way for enhancing UCL and will arouse extensive interest in noncontact temperature-sensing applications with a single red upconversion emission.

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Intense White Luminescence from Combustion Synthesized Ca12Al14O33: Yb3+/Yb2+ Single Phase Phosphor

Joshi

Kumar

2010

J Fluoresc

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The Ca(12)Al(14)O(33):Yb(3+)/Yb(2+) single phase nano-phosphor has been synthesized through combustion route and its luminescence and lifetime studies have been carried out up to 20 K using 976 and 266 nm excitations. The samples heated in open atmosphere have shown the presence of Yb in Yb(3+) and Yb(2+) states. The 976 nm excitation results a cooperative upconversion emission at 486 nm due to the Yb(3+) state and a broad band in the blue region and has been assigned to arise from the defect centers. The 266 nm excitation on the other hand results a broad emission band even from as-synthesized phosphor without doping of Yb, the width of which increases in presence of Yb due to the emission from Yb(2+) ions formed in heated samples. The white emission covers almost whole visible region with bandwidth 190 nm. The ions in Yb(2+) state has been found to increase with the increase in heating temperature up to 1,273 K. A back conversion of Yb(2+) to Yb(3+) has been observed for higher temperatures. Effect of boric and phosphoric acids as flux on the emission properties of Yb(3+) and Yb(2+) states have been examined and discussed. Quantum yield of emission has also been determined for different samples.

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Luminescence depolarization mechanisms for color centers with the luminescence peak at 670 nm in gamma-irradiated LiF:Mg crystals

Cited by 3 publications

References 1 publication

Up and down conversion fluorescence studies on combustion synthesized Yb3+/Yb2+: MO-Al2O3 (M=Ca, Sr and Ba) phosphors

Up and down conversion fluorescence studies on combustion synthesized Yb3+/Yb2+: MO-Al2O3 (M=Ca, Sr and Ba) phosphors

Giant Enhancement in Upconversion Luminescence of β-Ba₂ScAlO₅:Yb³⁺/Er³⁺ Phosphor by the Intermediate Band through Ca²⁺ Doping

Intense White Luminescence from Combustion Synthesized Ca12Al14O33: Yb3+/Yb2+ Single Phase Phosphor

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Luminescence depolarization mechanisms for color centers with the luminescence peak at 670 nm in gamma-irradiated LiF:Mg crystals

Cited by 3 publications

References 1 publication

Up and down conversion fluorescence studies on combustion synthesized Yb3+/Yb2+: MO-Al2O3 (M=Ca, Sr and Ba) phosphors

Up and down conversion fluorescence studies on combustion synthesized Yb3+/Yb2+: MO-Al2O3 (M=Ca, Sr and Ba) phosphors

Giant Enhancement in Upconversion Luminescence of β-Ba2ScAlO5:Yb3+/Er3+ Phosphor by the Intermediate Band through Ca2+ Doping

Intense White Luminescence from Combustion Synthesized Ca12Al14O33: Yb3+/Yb2+ Single Phase Phosphor

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Giant Enhancement in Upconversion Luminescence of β-Ba₂ScAlO₅:Yb³⁺/Er³⁺ Phosphor by the Intermediate Band through Ca²⁺ Doping