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Correlation among photoluminescence and the electronic and atomic structures of Sr2SiO4:xEu3+ phosphors: X-ray absorption and emission studies.
- Source :
- Scientific Reports; 7/29/2020, Vol. 10 Issue 1, p1-12, 12p
- Publication Year :
- 2020
-
Abstract
- A series of Eu<superscript>3+</superscript>-activated strontium silicate phosphors, Sr<subscript>2</subscript>SiO<subscript>4</subscript>:xEu<superscript>3+</superscript> (SSO:xEu<superscript>3+</superscript>, x = 1.0, 2.0 and 5.0%), were synthesized by a sol–gel method, and their crystalline structures, photoluminescence (PL) behaviors, electronic/atomic structures and bandgap properties were studied. The correlation among these characteristics was further established. X-ray powder diffraction analysis revealed the formation of mixed orthorhombic α'-SSO and monoclinic β-SSO phases of the SSO:xEu<superscript>3+</superscript> phosphors. When SSO:xEu<superscript>3+</superscript> phosphors are excited under ultraviolet (UV) light (λ = 250 nm, ~ 4.96 eV), they emit yellow (~ 590 nm), orange (~ 613 nm) and red (~ 652 and 703 nm) PL bands. These PL emissions typically correspond to 4f–4f electronic transitions that involve the multiple excited <superscript>5</superscript>D<subscript>0</subscript> → <superscript>7</superscript>F<subscript>J</subscript> levels (J = 1, 2, 3 and 4) of Eu<superscript>3+</superscript> activators in the host matrix. This mechanism of PL in the SSO:xEu<superscript>3+</superscript> phosphors is strongly related to the local electronic/atomic structures of the Eu<superscript>3+</superscript>–O<superscript>2−</superscript> associations and the bandgap of the host lattice, as verified by Sr K-edge and Eu L<subscript>3</subscript>-edge X-ray absorption near-edge structure (XANES)/extended X-ray absorption fine structure, O K-edge XANES and K<subscript>α</subscript> X-ray emission spectroscopy. In the synthesis of SSO:xEu<superscript>3+</superscript> phosphors, interstitial Eu<subscript>2</subscript>O<subscript>3</subscript>-like structures are observed in the host matrix that act as donors, providing electrons that are nonradiatively transferred from the Eu 5d and/or O 2p–Eu 4f/5d states (mostly the O 2p–Eu 5d states) to the <superscript>5</superscript>D<subscript>0</subscript> levels, facilitating the recombination of electrons that have transitioned from the <superscript>5</superscript>D<subscript>0</subscript> level to the <superscript>7</superscript>F<subscript>J</subscript> level in the bandgap. This mechanism is primarily responsible for the enhancement of PL emissions in the SSO:xEu<superscript>3+</superscript> phosphors. This PL-related behavior indicates that SSO:xEu<superscript>3+</superscript> phosphors are good light-conversion phosphor candidates for use in near-UV chips and can be very effective in UV-based light-emitting diodes. [ABSTRACT FROM AUTHOR]
- Subjects :
- PHOTOLUMINESCENCE
ELECTRONIC structure
ATOMIC structure
PHOSPHORS
X-ray absorption
Subjects
Details
- Language :
- English
- ISSN :
- 20452322
- Volume :
- 10
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Scientific Reports
- Publication Type :
- Academic Journal
- Accession number :
- 144825558
- Full Text :
- https://doi.org/10.1038/s41598-020-69428-7