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Co-crystallization of red emitting (NH4)3Sc(SO4)3: Eu3+ microfibers: structure--luminescence relationship for promising application in optical thermometry.
- Source :
- CrystEngComm; 7/14/2022, Vol. 24 Issue 26, p4819-4830, 12p
- Publication Year :
- 2022
-
Abstract
- The (NH<subscript>4</subscript>)3Sc(SO<subscript>4</subscript>)3:0.005Eu<superscript>3+</superscript> phosphor has been synthesized as rod-like microparticles by crystallization from an aqueous solution. Its crystal structure belongs to the monoclinic system, space group P2<subscript>1</subscript>1/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 <superscript>5</superscript>D<subscript>0</subscript> → <superscript>7</superscript>F<subscript>2</subscript> transitions in Eu<superscript>3+</superscript> ions. The absence of an inversion center in the sites occupied by Eu<superscript>3+</superscript> causes a high intensity of spectral lines at 602--642 nm associated with hypersensitive induced electric dipole <superscript>5</superscript>D<subscript>0</subscript> → <superscript>7</superscript>F<subscript>2</subscript> transitions. Heating of the (NH<subscript>4</subscript>)<subscript>3</subscript>Sc(SO<subscript>4</subscript>)<subscript>3</subscript>:0.005Eu<superscript>3+</superscript> sample to a temperature of 393 K is accompanied by considerable distortion of the Eu<superscript>3+</superscript> coordination by the phase transition, manifesting a gradual increase in the asymmetry ratio ( ) between the integral intensities of the lines at 602--642 nm (<superscript>5</superscript> D<subscript>4</subscript> → <superscript>7</superscript>F<subscript>2</subscript> transition) and at 581--602 nm (<superscript>5</superscript> D<subscript>0</subscript> → <superscript>7</superscript>F<subscript>1</subscript>). 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]
Details
- Language :
- English
- ISSN :
- 14668033
- Volume :
- 24
- Issue :
- 26
- Database :
- Complementary Index
- Journal :
- CrystEngComm
- Publication Type :
- Academic Journal
- Accession number :
- 157813906
- Full Text :
- https://doi.org/10.1039/d2ce00478j