Spectral Properties and Thermal Quenching of Mn{sup 4+} Luminescence in Silicate Garnet Hosts CaY{sub 2}MgMAlSi{sub 2}O{sub 12} (M = Al, Ga, Sc)
- Institute of Physics, University of Tartu (Estonia)
- Münster University of Applied Sciences (Germany)
- Kurnakov Institute of General and Inorganic Chemistry (Russian Federation)
Multi-component silicate garnet ceramics CaY{sub 2}MgMAlSi{sub 2}O{sub 12} comprising different cations M = Al, Ga or Sc in octahedral sites doped with Mn{sup 4+} ions have been synthesized and studied as novel red-emitting phosphors aiming at warm white pc-LED applications. All synthesized phosphors exhibit Mn{sup 4+} luminescence in rather deep red region, the shortest-wavelength spectrum of Mn{sup 4+} luminescence (peak wavelength at 668 nm) being obtained for the host with the largest cation M{sup 3+} = Sc{sup 3+} in the octahedral site. The effect of increasing the energy of the emitting Mn{sup 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{sup 4+}-ligand” bonding with increase of the interionic Mn{sup 4+}–O{sup 2–} distance. All studied phosphors demonstrate rather poor thermal stability of Mn{sup 4+} photoluminescence with a thermal quenching temperature T{sub 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{sup 2–}–Mn{sup 4+} charge-transfer state is observed with the increase of the M{sup 3+} cation radius, i.e. with the increase of the O{sup 2–}–Mn{sup 4+} interionic distance. The thermal quenching temperature of Mn{sup 4+} luminescence in the studied phosphors correlates with the energy of the O{sup 2–}–Mn{sup 4+} charge transfer state which is supposed to serve as a quenching state for Mn{sup 4+} luminescence.
- OSTI ID:
- 22925270
- Journal Information:
- Physics of the Solid State, Vol. 61, Issue 5; Other Information: Copyright (c) 2019 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7834
- Country of Publication:
- United States
- Language:
- English
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