| Autor: |
Pasechnik, Liliya A., Peshehonova, Alena O., Lipina, Olga A., Medyankina, Irina S., Enyashin, Andrey N., Chufarov, Alexander Yu., Tyutyunnik, Alexander P. |
| Předmět: |
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| Zdroj: |
CrystEngComm; 7/14/2022, Vol. 24 Issue 26, p4819-4830, 12p |
| Abstrakt: |
The (NH4)3Sc(SO4)3:0.005Eu3+ phosphor has been synthesized as rod-like microparticles by crystallization from an aqueous solution. Its crystal structure belongs to the monoclinic system, space group P211/C, = 4. An enantiotropic first-order phase transition from monoclinic to high-temperature rhombohedral structure (space group R3c) occurs at 350--355 K and compound decomposition begins only above 573 K. Under 248 nm excitation, the compound exhibits luminescence corresponding to the characteristic 5D0 → 7F2 transitions in Eu3+ ions. The absence of an inversion center in the sites occupied by Eu3+ causes a high intensity of spectral lines at 602--642 nm associated with hypersensitive induced electric dipole 5D0 → 7F2 transitions. Heating of the (NH4)3Sc(SO4)3:0.005Eu3+ sample to a temperature of 393 K is accompanied by considerable distortion of the Eu3+ coordination by the phase transition, manifesting a gradual increase in the asymmetry ratio ( ) between the integral intensities of the lines at 602--642 nm (5 D4 → 7F2 transition) and at 581--602 nm (5 D0 → 7F1). When the heating is suppressed, the level returns to the original value, confirming the reversibility of the structural transformation. A good reproducibility of the obtained values has been revealed during 4-fold thermal cycling. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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