Synthesis, neutron diffraction and photoluminescence properties of a whitlockite structured Ca9MgLi(PO4)7:Pr3+ phosphor
| Autor: | Huihua Zhou, Li Yin, Peng Cao, Obert P. Golim, Wei Gao, Saifang Huang, Tilo Söhnel, Tingxuan Yang |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Photoluminescence Materials science Process Chemistry and Technology Neutron diffraction Doping Phosphor 02 engineering and technology Crystal structure engineering.material 021001 nanoscience & nanotechnology 01 natural sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Crystallography 0103 physical sciences Materials Chemistry Ceramics and Composites Whitlockite engineering Chromaticity 0210 nano-technology Powder diffraction |
| Zdroj: | Ceramics International. 46:27476-27483 |
| ISSN: | 0272-8842 |
| DOI: | 10.1016/j.ceramint.2020.07.236 |
| Popis: | The whitlockite structured compound Ca9MgLi(PO4)7 has been investigated as a potential host material for down-conversion phosphors. However, no detailed crystal structure and crystallographic site occupancy have been reported for this compound previously. In this work, Pr3+ activated Ca9MgLi(PO4)7 phosphors were successfully synthesized, and the structure and photoluminescence properties were characterized. Upon neutron and X-ray powder diffraction data, the crystallographic site occupancies of M1-M5 in the whitlockite-type structure were carefully refined by the Rietveld method. The M1, M2 and M3 sites are all found to be 8-fold coordinated and fully occupied with Ca and Pr. The results also revealed that the M4 and M5 sites are co-occupied by Li–Mg and Ca–Mg, respectively. Photoluminescence (PL) study showed that the phosphor has a characteristic excitation band at the visible light region of 430–500 nm. Three peaks observed at 442, 468, and 484 nm in the excitation spectra can be ascribed to the 3H4→3P2, 3H4→3P1, and 3H4→3P0 transition of Pr3+, respectively. The phosphor doped with 0.02 Pr3+ gives the strongest emission peaked at 612 nm, with the CIE chromaticity coordinate of (0.613, 0.366). This reddish-orange emitting phosphor has good thermal stability that it retains 83% of its emission intensity at 200 °C. Energy transfer mechanism of the activators was analyzed to be dipole-dipole multipolar interaction. The present work demonstrates that Ca9MgLi(PO4)7:Pr3+ is a promising phosphor for blue-pumped white light-emitting diodes (WLEDs). |
| Databáze: | OpenAIRE |
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