Incommensurately modulated structure and spectroscopic properties of CaGd2(MoO4)4:Ho3+/Yb3+ phosphors for up-conversion applications
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http://www.sciencedirect.com/science/article/pii/S0925838816318576https://elib.sfu-kras.ru/handle/2311/70249
Автор:
Chang, Sung Lim
Victor V. Atuchin
Aleksandr S. Aleksandrovsky
Maxim S. Molokeev
Aleksandr S. Oreshonkov
Коллективный автор:
Институт нанотехнологий, спектроскопии и квантовой химии
Дата:
2017-02Журнал:
Journal of Alloys and CompoundsКвартиль журнала в Scopus:
Q1Квартиль журнала в Web of Science:
Q1Библиографическое описание:
Chang, Sung Lim. Incommensurately modulated structure and spectroscopic properties of CaGd2(MoO4)4:Ho3+/Yb3+ phosphors for up-conversion applications [Текст] / Sung Lim Chang, Victor V. Atuchin, Aleksandr S. Aleksandrovsky, Maxim S. Molokeev, Aleksandr S. Oreshonkov // Journal of Alloys and Compounds. — 2017. — Т. 695. — С. 737-746Аннотация:
CaGd2(MoO4)4:Ho3þ/Yb3þ phosphors doped by Ho3þ and Yb3þ (Ho3þ ¼ 0 and 0.05, and Yb3þ ¼ 0, 0.35,
0.40, 0.45 and 0.50) were successfully synthesized by the microwave sol-gel method. The synthesized
particles, being formed after heat-treatment at 900 C for 16 h, showed a well crystallized morphology.
All compounds are (3 þ 2)D incommensurately modulated with superspace group I41/a(a,b,0)00(-b,a,0)
00. It was found that parameter (a2 þ b2)1/2 is proportional to cell parameter a for all studied compositions
and, therefore, modulation vector k is the same for all known CaRE2(MoO4)4 compounds. The
modulation vector invariance is a specific and valuable feature of this type of the structure. Under the
excitation at 980 nm, the doped particles exhibited the yellow emission composed of green (545-nm)
and red (655-nm) emission bands due to frequency upconversion (UC). The pump power dependence
and CIE chromaticity of the UC emission were evaluated. The shape of UC bands in CaGd2(MoO4)4:Ho3þ/
Yb3þ is dependent on the Yb content due to the influence of the crystal field affecting a holmium ion. 13
Raman-active modes of the CaGd2(MoO4)4 lattice were identified via a comparison of experimental
Raman spectra and the lattice dynamics simulation results. Four additional Raman lines were found in
the region of stretching vibrations and, at least, two additional modes are present in the bending mode
region. These additional modes are ascribed to incommensurate crystal lattice modulation. Luminescence
bands of Ho ions are severely broadened due to a statistical disorder in the CaGd2 xYby (MoO4)4
lattice.