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This article is cited in 1 scientific paper (total in 1 paper)
XVII International Theophilov Symposium, Yekaterinburg, September 23-28, 2018
Optical properties
Spectral properties and thermal quenching of Mn$^{4+}$ luminescence in silicate garnet hosts CaY$_{2}$MgMAlSi$_{2}$O$_{12}$ ($M$ = Al, Ga, Sc)
M. Kirma, M. Ojaa, J. Kozlovaa, H. Mändara, S. Vielhauera, T. Jansenb, T. Jüstelb, N. M. Khaidukovc, V. N. Makhovd a Institute of Physics, University of Tartu, Tartu, Estonia
b Münster University of Applied Sciences, Steinfurt, Germany
c Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow
d P. N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow
Abstract:
Multi-component silicate garnet ceramics CaY$_{2}$MgMAlSi$_{2}$O$_{12}$ comprising different cations $M$ = Al, Ga or Sc in octahedral sites doped with Mn$^{4+}$ ions have been synthesized and studied as novel red-emitting phosphors aiming at warm white $pc$-LED applications. All synthesized phosphors exhibit Mn$^{4+}$ luminescence in rather deep red region, the shortest-wavelength spectrum of Mn$^{4+}$ luminescence (peak wavelength at 668 nm) being obtained for the host with the largest cation $M^{3+}$ = Sc$^{3+}$ in the octahedral site. The effect of increasing the energy of the emitting Mn$^{4+}$ ${}^{2}E$ level with the size of the host cation in octahedral sites is supposed to be the result of decrease of the covalence of the "Mn$^{4+}$-ligand" bonding with increase of the interionic Mn$^{4+}$–O$^{2-}$ distance. All studied phosphors demonstrate rather poor thermal stability of Mn$^{4+}$ photoluminescence with a thermal quenching temperature $T_{1/2}$ below 200 K, the lowest value being observed for the host with $M$ = Sc. As expected, the decrease of the energy of the O$^{2-}$–Mn$^{4+}$ charge-transfer state is observed with the increase of the $M^{3+}$ cation radius, i. e. with the increase of the O$^{2-}$–Mn$^{4+}$ interionic distance. The thermal quenching temperature of Mn$^{4+}$ luminescence in the studied phosphors correlates with the energy of the O$^{2-}$–Mn$^{4+}$ charge transfer state which is supposed to serve as a quenching state for Mn$^{4+}$ luminescence.
Citation:
M. Kirm, M. Oja, J. Kozlova, H. Mändar, S. Vielhauer, T. Jansen, T. Jüstel, N. M. Khaidukov, V. N. Makhov, “Spectral properties and thermal quenching of Mn$^{4+}$ luminescence in silicate garnet hosts CaY$_{2}$MgMAlSi$_{2}$O$_{12}$ ($M$ = Al, Ga, Sc)”, Fizika Tverdogo Tela, 61:5 (2019), 952; Phys. Solid State, 61:5 (2019), 853–859
Linking options:
https://www.mathnet.ru/eng/ftt8832 https://www.mathnet.ru/eng/ftt/v61/i5/p952
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