High-Pressure Low-Temperature Optical Studies of BaWO4:Ce,Na Crystals.
Inorg Chem
; 58(9): 5617-5629, 2019 May 06.
Article
in En
| MEDLINE
| ID: mdl-30998007
ABSTRACT
We report detailed optical studies of BaWO4Ce and BaWO4Ce,Na single crystals. The material does not emit any luminescence at ambient pressure under near-UV (325 nm) excitation. Efficient green light is emitted only at high pressure (HP) and low temperature (LT). The luminescence is of excitonic character, since the lowest Ce3+ 5d level is degenerate with the conduction band also under hydrostatic pressures. To explain these phenomena, absorption measurements were made together with powder X-ray diffraction (XRD) and confocal micro-Raman and Fourier transform infrared (FTIR) spectroscopy. Raman experiments confirm the existence of a metastable phase, induced by certain nonhydrostatic conditions, before the reversible transition at a high-pressure range above 9 GPa, where efficient photoluminescence (PL) occurs. Although the phase transition is reversible, it proceeds with a prominent hysteresis observed in luminescence and Raman experiments. FTIR focuses on the existence of Ce3+ multisites observed during LT measurements.
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01-internacional
Database:
MEDLINE
Language:
En
Journal:
Inorg Chem
Year:
2019
Document type:
Article
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