title: NaGd(MoO4)2 nanocrystals with diverse morphologies: controlled synthesis, growth mechanism, photoluminescence and thermometric properties.
abstract: Pure tetragonal phase, uniform and well-crystallized sodium gadolinium molybdate (NaGd(MoO4)2) nanocrystals with diverse morphologies, e.g. nanocylinders, nanocubes and square nanoplates have been selectively synthesized via oleic acid-mediated hydrothermal method. The phase, structure, morphology and composition of the as-synthesized products are studied. Contents of both sodium molybdate and oleic acid of the precursor solutions are found to affect the morphologies of the products significantly, and oleic acid plays a key role in the morphology-controlled synthesis of NaGd(MoO4)2 nanocrystals with diverse morphologies. Growth mechanism of NaGd(MoO4)2 nanocrystals is proposed based on time-dependent morphology evolution and X-ray diffraction analysis. Morphology-dependent down-shifting photoluminescence properties of NaGd(MoO4)2: Eu(3+) nanocrystals, and upconversion photoluminescence properties of NaGd(MoO4)2: Yb(3+)/Er(3+) and Yb(3+)/Tm(3+) nanoplates are investigated in detail. Charge transfer band in the down-shifting excitation spectra shows a slight blue-shift, and the luminescence intensities and lifetimes of Eu(3+) are decreased gradually with the morphology of the nanocrystals varying from nanocubes to thin square nanoplates. Upconversion energy transfer mechanisms of NaGd(MoO4)2: Yb(3+)/Er(3+), Yb(3+)/Tm(3+) nanoplates are proposed based on the energy level scheme and power dependence of upconversion emissions. Thermometric properties of NaGd(MoO4)2: Yb(3+)/Er(3+) nanoplates are investigated, and the maximum sensitivity is determined to be 0.01333 K(-1) at 285 K.
authors: State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering/School of Physics, Sun Yat-sen University, Guangzhou, 510275, China.|Institute of Optoelectronic Engineering, Department of Optoelectronic Engineering, Jinan University, Guangzhou, 510632, China.
authors: Anming
authors: A
authors: Li
authors: State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering/School of Physics, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Dekang
authors: D
authors: Xu
authors: State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering/School of Physics, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Hao
authors: H
authors: Lin
authors: State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering/School of Physics, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Shenghong
authors: S
authors: Yang
authors: State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering/School of Physics, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Yuanzhi
authors: Y
authors: Shao
authors: State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering/School of Physics, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Yueli
authors: Y
authors: Zhang