Dependence of cross-relaxation on temperature and concentration from the 1D2 level of Pr3+ in YPO4

Collins, John; Geen, M.; Bettinelli, Marco; Bartolo, Baldassare Di

doi:10.1016/j.jlumin.2012.04.027

Cited by 40 publications

(16 citation statements)

References 19 publications

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“…They reported that the 1 D 2 ‐system is radiative only in low Pr 3+ concentrations. As the concentration increases, the luminescence is quenched . The two peaks at 614 and 618 nm are attributed to the 3 P 0 → 3 H 6 transition, reaching their highest intensity at 3% Pr 3+ …”

Section: Resultsmentioning

confidence: 99%

Deep Ultraviolet Emitting Scintillators for Biomedical Applications: The Hard Way of Downsizing LuPO₄:Pr³⁺

Espinoza

Volhard

Kätker

et al. 2018

Part & Part Syst Charact

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Pr3+‐doped LuPO4 emits UV radiation between 225 and 280 nm, where DNA shows strong absorption bands. Therefore, a systematic study of the luminescence of Pr3+ doped LuPO4 is performed: Different doping concentrations, particles sizes, and excitation schemes (vacuum UV at 160 nm and X‐rays 50 kV, 2 mA, tungsten target) are compared. The emission spectra in the UV range depends on the excitation energy and the particle size. Microcrystalline particles (6 µm) comprising 1% Pr3+ display the highest emission intensity at 234 nm upon vacuum UV as well as X‐ray excitation. Sub‐microscale particles (20–50 nm) of LuPO4:Pr3+ (1%) show the same UV emission under X‐ray excitation as the larger particles but do not emit under vacuum UV excitation. Colloidal nanoscale particles (5 nm) do not show emission in the UV‐C range. Based on the high‐density and strong X‐ray absorption of LuPO4, the implementation of Pr3+ doped LuPO4 particles of suitable size (20–50 nm) could improve the well‐established radiation therapy. Owing to the strong absorption and low penetration depth of UV‐C radiation in biological tissue, Pr3+‐doped LuPO4 particles located directly in cancerous tumors could allow for additional treatment with cell‐damaging UV‐C radiation.

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Section: Resultsmentioning

confidence: 99%

Deep Ultraviolet Emitting Scintillators for Biomedical Applications: The Hard Way of Downsizing LuPO₄:Pr³⁺

Espinoza

Volhard

Kätker

et al. 2018

Part & Part Syst Charact

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“…Several studies have observed that the emission of the 1 D 2 → 3 H 4 transition of Pr 3+ disappears upon increasing the Pr 3+ concentration . In this case, the Pr 3+ concentration was kept at 1% in all samples.…”

Section: Resultsmentioning

confidence: 97%

“…However, a reduced intensity of the peaks observed at around 600 nm can be clearly recognized (inset). These peaks have been attributed to the 1 D 2 → 3 H 4 and 3 P 0 → 3 H 6 transitions of the Pr 3+ ion …”

Section: Resultsmentioning

confidence: 99%

Characterization of Micro‐ and Nanoscale LuPO₄:Pr³⁺,Nd³⁺ with Strong UV‐C Emission to Reduce X‐Ray Doses in Radiation Therapy

Espinoza

Müller

Jenneboer

et al. 2019

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UV‐C emitting nanoscale scintillators can be used to sensitize cancer cells selectively against X‐rays during radiation therapy, due to the lethal DNA lesions caused by UV‐C photons. Unfortunately, nanoscale particles (NPs) show decreased UV‐C emission intensity. In this paper, the influence of different Nd3+ concentrations on the UV‐C emission of micro‐ and nanoscale LuPO4:Pr3+ is investigated upon X‐ray irradiation and vacuum UV excitation (160 nm). Co‐doped LuPO4 results in increased UV‐C emission independent of excitation source due to energy transfer from Nd3+ to Pr3+. The highest UV‐C emission intensity is observed for LuPO4:Pr3+,Nd3+(1%,2.5%) upon X‐ray irradiation. Finally, LuPO4 NPs co‐doped with different dopant concentrations are synthesized, and the biological efficacy of the combined approach (X‐rays and UV‐C) is assessed using the colony formation assay. Cell culture experiments confirm increased cell death compared to X‐rays alone due to the formation of UV‐specific DNA damages, supporting the feasibility of this approach.

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“…The decay curve of the 614 nm Eu 3+ emission was not a single exponential but nonexponential. Therefore average decay times were determined using the same method of Collins et al…”

Section: The Energy‐transfer Efficiencymentioning

confidence: 99%

Emission from Mo‐O charge‐transfer state and Yb³⁺ emission in Eu³⁺‐doped and nondoped molybdates under UV excitation

Qiao

Tsuboi

2017

J Am Ceram Soc

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Molybdates of Li + and Yb 3+ are studied to investigate the luminescence under UV excitation. LiYb(MoO 4 ) 2 and Eu 3+ -doped LiYb 1x Eux(MoO 4 ) 2 (x=001-1.0) phosphors were synthesized by solid state reaction under mixing of Eu 2 O 3 , Yb 2 O 3 , Li 2 CO 3 and MoO 2 in air atmosphere. Two broad absorption bands centered at 333 and 236 nm are observed in LiYb(MoO 4 ) 2 compound. They are attributed to the 1 A 1 ? 1 T 1 and 1 T 2 transitions due to the O 2À ?Mo 6+ electron transfers in MoO 4 tetrahedron. An emission band with a peak at about 440 nm is found, which is attributed to the 3 T 1 ? 1 A 1 transition of MoO 4 . Appearance of near-infrared (NIR) Yb 3+ emission observed under UV excitation is understood by the MoO 4 ?Yb 3+ Foerster-Type energy transfer due to spectral overlap between the low-energy tail of the broad 440 nm emission band and the high-energy tail of the broad Yb 3+ absorption band and due to short Yb 3+ -MoO 4 distance. Yb 3+ emission observed in LiYb 1Àx Eu x (MoO 4 ) 2 by Eu 3+ excitation is understood by the Eu 3+ ?Yb 3+ energy transfer by cross-relaxation (CR) process between the 5 D 0 ? 7 F 6 Eu 3+ transition and the 2 F 7/2 ? 2 F 5/2 Yb 3+ transition. The CR efficiency shows maximum efficiency of 0.24 at x=0.15 of higher acceptor Yb 3+ concentration than donor Eu 3+ concentration. Three Yb 3+ emission bands with peaks at 994, 1002, and 1023 nm are observed, depending on the excitation wavelength. This is explained by less-shielded 4f electrons of Yb 3+ by the 5s 2 5p 6 outermost electron shells, which are also responsible for unusual broadband Yb 3+ absorption and emission. From appearance of NIR Yb 3+ emission under excitation by not only UV light but also red light, these compounds are expected to be suitable for efficient photovoltaic application to Si-based solar cells. K E Y W O R D S europium, fluorescence, optical materials/properties, phosphors, ytterbium, photoluminescence

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Dependence of cross-relaxation on temperature and concentration from the 1D2 level of Pr3+ in YPO4

Cited by 40 publications

References 19 publications

Deep Ultraviolet Emitting Scintillators for Biomedical Applications: The Hard Way of Downsizing LuPO₄:Pr³⁺

Deep Ultraviolet Emitting Scintillators for Biomedical Applications: The Hard Way of Downsizing LuPO₄:Pr³⁺

Characterization of Micro‐ and Nanoscale LuPO₄:Pr³⁺,Nd³⁺ with Strong UV‐C Emission to Reduce X‐Ray Doses in Radiation Therapy

Emission from Mo‐O charge‐transfer state and Yb³⁺ emission in Eu³⁺‐doped and nondoped molybdates under UV excitation

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Dependence of cross-relaxation on temperature and concentration from the 1D2 level of Pr3+ in YPO4

Cited by 40 publications

References 19 publications

Deep Ultraviolet Emitting Scintillators for Biomedical Applications: The Hard Way of Downsizing LuPO4:Pr3+

Deep Ultraviolet Emitting Scintillators for Biomedical Applications: The Hard Way of Downsizing LuPO4:Pr3+

Characterization of Micro‐ and Nanoscale LuPO4:Pr3+,Nd3+ with Strong UV‐C Emission to Reduce X‐Ray Doses in Radiation Therapy

Emission from Mo‐O charge‐transfer state and Yb3+ emission in Eu3+‐doped and nondoped molybdates under UV excitation

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Product

Resources

About

Deep Ultraviolet Emitting Scintillators for Biomedical Applications: The Hard Way of Downsizing LuPO₄:Pr³⁺

Deep Ultraviolet Emitting Scintillators for Biomedical Applications: The Hard Way of Downsizing LuPO₄:Pr³⁺

Characterization of Micro‐ and Nanoscale LuPO₄:Pr³⁺,Nd³⁺ with Strong UV‐C Emission to Reduce X‐Ray Doses in Radiation Therapy

Emission from Mo‐O charge‐transfer state and Yb³⁺ emission in Eu³⁺‐doped and nondoped molybdates under UV excitation