| Title | (Gd,Yb,Tb)PO 4 up-conversion nanocrystals for bimodal luminescence-MR imaging
|
| Publication Type | Journal Article |
| 2012 |
| Authors | Debasu, ML, Ananias, D, Pinho, SLC, Geraldes, CFGC, Carlos, LD, Rocha, J |
| Journal | NanoscaleNanoscale |
| Volume | 4 |
| Issue | 16 |
| Pagination | 5154 - 5162 |
| Date Published | 2012/// |
| 20403364 (ISSN) |
| Blue-emission, Calcination, Calcination temperature, Concentration ratio, Continuous wave lasers, Contrast agent, Gadolinium, Hydrothermal methods, Infrared excitation, Magnetic resonance, Magnetic resonance imaging, Nanocrystals, Relaxometry, Up-conversion, Up-conversion emission, Visible light, Ytterbium |
| Up-conversion (Gd,Yb,Tb)PO 4 materials and their potential for bimodal imaging have received little attention in the literature. Herein, we report the first study on the up-conversion emission of (Gd,Yb,Tb)PO
4 nanocrystals synthesized via a hydrothermal method at 150°C. These materials exhibit ultraviolet, blue and green up-conversion emissions upon excitation with a 980 nm continuous wave laser diode. The intensity of the blue-emission band at 479 nm, ascribed to the cooperative up-conversion emission of a pair of excited Yb
3+ ions, depends on the Yb
3+/Tb
3+ concentration ratio, calcination temperature and particle size. Strong green up-conversion emission of Tb
3+ is observed at 543 nm for the
5D
4 →
7F
5 transition. Relaxometry measurements reveal that the nanocrystals are efficient T
2-weighted (negative) contrast agents which, combined with visible-light emission generated by infrared excitation, affords them considerable potential for being used in bimodal, photoluminescence-magnetic resonance, imaging. © 2012 The Royal Society of Chemistry.
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