Optimization of synthesis and compositional parameters of magnesium germanate and fluoro-germanate thermographic phosphors

Ali, Amjad; Khanzada, Laraib S.; Hashemi, Amir; Polzer, Carsten; Osvet, Andres; Brabec, Christoph J.; Batentschuk, Miroslaw

doi:10.1016/j.jallcom.2017.10.259

Cited by 10 publications

(6 citation statements)

References 28 publications

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“…125 On the other hand, the range for the "oxide" phosphors in Fig. 36b is very wide, from ∼ 640 nm (Mg 4 GeO 6 :Mn 4+ ), 193 via ∼ 675 nm (Ba 2 YNbO 6 :Mn 4+ ), 83 to ∼ 715 nm (LaAlO 3 :Mn 4+ ). 194 As expected, the range for the "oxyfluoride" phosphors falls between those for the fluoride and oxide phosphors, i.e., from ∼ 620 nm (Na 2 WO 2 F 4 :Mn 4+ ) 34 to ∼ 685 nm (Sr 2 ScO 3 F:Mn 4+ ).…”

Section: Displaying Device and Indoor Plant Cultivation Applicationsmentioning

confidence: 98%

“…Such red-emitting phosphors can, therefore, be used in w-LED lamps, leading to a significant reduction in the efficacy gap between warm and cool w-LED lamps employing down-conversion red-emitting Mn 4+ -activated phosphors. 71,125 IV (oxide), 83,193,194 and V (oxyfluoride). 34,195 The vertical arrows in each figure show the positions of the E( 2 E g ) ZPL emission energy (ZPL).…”

Section: Displaying Device and Indoor Plant Cultivation Applicationsmentioning

confidence: 99%

“…Room-temperature PL spectra for (a) some Mn 4+ -activated fluoride, (b) oxide, and (c) oxyfluoride phosphors. Note that the phosphors selected here have the lowest and highest ZPL emission energies in each group of Tables II (fluoride),71,125 IV (oxide),83,193,194 and V (oxyfluoride) 34,195. The vertical arrows in each figure show the positions of the E( 2 E g ) ZPL emission energy (ZPL).…”

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confidence: 99%

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Review—Mn⁴⁺-Activated Red and Deep Red-Emitting Phosphors

Adachi

2019

ECS J. Solid State Sci. Technol.

133

285

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Mn4+-activated phosphors are a new class of non-rare earth phosphors and are alternative to commercial Eu2+-activated nitride/oxynitride phosphors with growing interest in various applications. In this review article, the structural and photoluminescence (PL) properties of various Mn4+-activated phosphors have been discussed. The host materials considered here can be roughly classified into five groups; fluorides, oxides, oxyfluorides, and two fluorine compounds. Phosphors of each group can also be classified into totally eleven subgroups from their different PL spectral features, e.g., whether an appearance of the zero-phonon line (ZPL) emission peak or not. The ZPL emission and absorption energies of the Mn4+ ions have been determined from the PL and PL excitation spectra using the Franck−Condon analysis method within the configurational-coordinate (CC) model. These results are used to obtain reliable phosphor parameters, i.e., the crystal-field (Dq) and Racah parameters (B and C), of the Mn4+ ions in the various host materials. The PL intensity vs temperature data, together with those of the luminescence lifetimes, are modeled on the basis of the CC model, and an excellent agreement has been achieved if not only the optical phonon but also the acoustic phonon contribution is taken into consideration in the conventional thermal quenching model. Effects of the hydrostatic pressure and dopant concentration on the PL spectral features are also discussed. Finally, key properties of the Mn4+-activated phosphors are discussed for use of such red and deep red-emitting phosphor systems in warm w-LED and indoor plant cultivation applications.

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Section: Displaying Device and Indoor Plant Cultivation Applicationsmentioning

confidence: 98%

Section: Displaying Device and Indoor Plant Cultivation Applicationsmentioning

confidence: 99%

mentioning

confidence: 99%

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Review—Mn⁴⁺-Activated Red and Deep Red-Emitting Phosphors

Adachi

2019

ECS J. Solid State Sci. Technol.

133

285

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“…Above a certain temperature, phonon relaxation will dominate over radiative relaxation and there will be no more emission (the phosphor is quenched). Phosphors suitable for thermographic use have a monotonic temperature dependence beyond a simple decrease in intensity, and temperature can be determined either from a change of time constant of the phosphor decay [19] or from changes in the emitted spectrum [20].…”

Section: Phosphor Thermometrymentioning

confidence: 99%

Toward Gamma Ray Immune Fibre-Optic Phosphor Thermometry for Nuclear Decommissioning

et al. 2022

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Temperature measurement of stored nuclear waste is important for long-term monitoring. Conventional sensors can degrade in ionizing radiation from induced transmutations and their frequent replacement is inconvenient. A thermometer based on suitable phosphors can overcome some problems, but the optical signal needs to be transmitted through an optical fibre and processed remotely away from the dangerous area. This requires that the optical fibre itself be suitably resistant to radiation-induced damage. Here, we report transmission measurements through a type of hollow-core fibre based on anti-resonance and with transmission windows at wavelengths suitable for use with the thermographic phosphor magnesium fluorogermanate whilst subjected to gamma radiation. Its performance is compared to commercially available standard fibres (single mode and radiation hard fibres) at dose rates equivalent to decades of use in a storage facility. Transmission was unchanged for the anti-resonant fibre at the phosphor emission wavelength and it was successfully incorporated into a fibre thermometer that worked from $${20}\,^{\circ }\hbox {C}$$ 20 ∘ C to $$200\,^{\circ }\hbox {C}$$ 200 ∘ C . Performance at the phosphor excitation wavelength needs to be improved by modification to the hollow-core fibre design, but we show that a hybrid of single mode and anti-resonant fibres can already be made into a thermometer with suitable gamma immunity.

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“…Some phosphors show multiple spectral features [10], and the relative intensity of these can depend on temperature. As a result, spectral measurement can be used to determine the phosphor temperature.…”

Section: Principle Of Phosphor Thermometrymentioning

confidence: 99%

Design, construction and traceable calibration of a phosphor-based fibre-optic thermometer from 0 °C to 650 °C

Lowe

Sutton

Sposito

et al. 2021

Meas. Sci. Technol.

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Measurement traceability, in which there is a documented chain of calibration links from a measurement back to a primary realisation of a unit, is vital for achieving the smallest uncertainty in metrology. A sensor that can provide a traceable link in harsh environments may be advantageous even if its uncertainty is larger than that of typical calibrated devices. A phosphor-based thermometer that has optical rather than electrical connections has been built and then calibrated in terms of the International Temperature Scale of 1990. Its standard uncertainty ranges from 0.5 °C at 0 °C to 2 °C at 650 °C. While this uncertainty cannot match what is possible with thermocouples or resistance thermometers, the optical basis of the sensor means it can be used in situations where electrical connections are precluded.

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Optimization of synthesis and compositional parameters of magnesium germanate and fluoro-germanate thermographic phosphors

Cited by 10 publications

References 28 publications

Review—Mn⁴⁺-Activated Red and Deep Red-Emitting Phosphors

Review—Mn⁴⁺-Activated Red and Deep Red-Emitting Phosphors

Toward Gamma Ray Immune Fibre-Optic Phosphor Thermometry for Nuclear Decommissioning

Design, construction and traceable calibration of a phosphor-based fibre-optic thermometer from 0 °C to 650 °C

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Optimization of synthesis and compositional parameters of magnesium germanate and fluoro-germanate thermographic phosphors

Cited by 10 publications

References 28 publications

Review—Mn4+-Activated Red and Deep Red-Emitting Phosphors

Review—Mn4+-Activated Red and Deep Red-Emitting Phosphors

Toward Gamma Ray Immune Fibre-Optic Phosphor Thermometry for Nuclear Decommissioning

Design, construction and traceable calibration of a phosphor-based fibre-optic thermometer from 0 °C to 650 °C

Contact Info

Product

Resources

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Review—Mn⁴⁺-Activated Red and Deep Red-Emitting Phosphors

Review—Mn⁴⁺-Activated Red and Deep Red-Emitting Phosphors