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Concentration quenching of blue upconversion luminescence in Tm3+/Yb3+ co-doped Gd2(WO4)3 phosphors under 980 and 808 nm excitation.
- Source :
-
Journal of Alloys & Compounds . Jun2017, Vol. 709, p147-157. 11p. - Publication Year :
- 2017
-
Abstract
- This paper reported on the upconversion (UC) spectroscopic properties of Tm 3+ /Yb 3+ codoped Gd 2 (WO 4 ) 3 phosphors synthesized by a traditional co-precipitation method upon excitation of 980 and 808 nm commercial available fiber lasers, respectively. X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were used to characterize the crystal structure and morphology of the samples. Intense blue emission ( 1 G 4 → 3 H 6 ) and near-infrared (NIR) emission ( 3 H 4 → 3 H 6 ) as well as weak red emission ( 1 G 4 → 3 F 4 ) of Tm 3+ were observed under 980 nm excitation. The concentration quenching processes for blue and NIR emissions were discussed. The blue emission intensity has a cubic dependence on the fiber laser working current, indicating a three-photon process involved in blue UC emission. The blue emission and its concentration quenching process for Tm 3+ /Yb 3+ codoped Gd 2 (WO 4 ) 3 phosphors were also investigated under 808 nm excitation. Weak blue emission ( 1 D 2 → 3 F 4 ) was detected in the UC spectra other than the weak red emissions ( 1 G 4 → 3 F 4 , 3 F 2,3 → 3 H 6 ). The dominant mechanism for blue emission under 808 nm excitation was attributed to the back energy transfer (BET) Tm 3+ → Yb 3+ and the energy transfer (ET) Yb 3+ → Tm 3+ processes. Upon 808 nm excitation, a two-photon process was deduced from the quadratic dependence of blue UC emission intensity on the fiber laser working current. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09258388
- Volume :
- 709
- Database :
- Academic Search Index
- Journal :
- Journal of Alloys & Compounds
- Publication Type :
- Academic Journal
- Accession number :
- 122528038
- Full Text :
- https://doi.org/10.1016/j.jallcom.2017.03.125