Перевод заглавия: Структурный фазовый переход и люминесцентные свойства ортосиликата Ca2-xSrxSiO4:Ce3+
Рубрики:
LIGHT-EMITTING-DIODES
DICALCIUM SILICATE
CRYSTAL-STRUCTURE
SOLID-SOLUTION
BOND-VALENCE
Ce3+
Eu2+
β-Ca2SiO4
GREEN
TEMPERATURE
LIGHT-EMITTING-DIODES
DICALCIUM SILICATE
CRYSTAL-STRUCTURE
SOLID-SOLUTION
BOND-VALENCE
Ce3+
Eu2+
β-Ca2SiO4
GREEN
TEMPERATURE
Аннотация: The orthosilicate phosphors demonstrate great potential in the field of solid-state lighting, and the understanding of the structure-property relationships depending on their versatile polymorphs and chemical compositions is highly desirable. Here we report the structural phase transformation of Ca2-xSrxSiO4:Ce3+ phosphor by Sr2+ substituting for Ca2+ within 0 ≤ x 2. The crystal structures of Ca2-xSrxSiO4:Ce3+ are divided into two groups, namely, β phase (0 ≤ x 0.15) and α′ phase (0.18 ≤ x 2), and the phase transition (β → α′) mechanism originated from the controlled chemical compositions is revealed. Our findings verified that the phase transition Pnma (α′-phase) ↔ P21/n (β-phase) can be ascribed to the second-order type, and Sr2+ ions in Ca2-xSrxSiO4 preferentially occupy the seven-coordinated Ca2+ sites rather than the eight-coordinated sites with increasing Sr2+ content, which was reflected from the Rietveld refinements and further clarified through the difference of the Ca-O bond length in the two polymorphs of Ca2SiO4. The emission peaks of Ce3+ shift from 417 to 433 nm in the composition range of 0 ≤ x ≤ 0.8, and the difference in the decay curves can also verify the phase transformation process. Thermal quenching properties of selected Ca2-xSrxSiO4:Ce3+ samples were evaluated, and the results show that the integral emission intensities at 200 °C maintain 90% of that at room temperature suggesting superior properties for the application as white light-emitting diodes (w-LEDs) phosphors. © 2015 American Chemical Society.
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Держатели документа:
School of Materials Sciences and Engineering, University of Science and Technology Beijing, Beijing, China
Laboratory of Crystal Physics, Kirensky Institute of Physics, SB RAS, Krasnoyarsk, Russian Federation
Department of Physics, Far Eastern State Transport University, Khabarovsk, Russian Federation
Доп.точки доступа:
Chen, M.; Xia, Z.; Molokeev, M. S.; Молокеев, Максим Сергеевич; Liu, Q.
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