1. Dicarboxylate mediated efficient morphology/phase tailoring of YPO4:Ln3+ crystals and investigation of down-/up-conversion luminescence.
- Author
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Wang, Zhihao, Li, Ji-Guang, Zhu, Qi, Kim, Byung-Nam, and Sun, Xudong
- Subjects
CARBOXYLATES ,CRYSTAL structure ,LUMINESCENCE - Abstract
The dicarboxylate anions of tartrate (C
4 H4 O6 2− , Tar2− ), malate (C4 H4 O5 2− , Mal2− ), and succinate (C4 H4 O4 2− , Suc2− ) were originally used as morphology/structure modifiers in the hydrothermal crystallization of YPO4 , and both hexagonal (h-) and tetragonal (t-) structured crystals with multiform morphologies of high uniformity were selectively synthesized. The materials were characterized by the combined techniques of XRD, FE-SEM, TEM, FT-IR, TG, and optical spectroscopy, and the mechanisms of phase/morphology evolution were expatiated. It was clearly shown that Tar2− may induce an inverse phase transformation of YPO4 from the thermodynamically stable tetragonal structure (nanoparticles) to the metastable hexagonal structure (microprisms), and a series of controlled experiments exhibited that the performance of Tar2− was strongly affected by the experimental parameters of Tar2− /PO4 3− /Y3+ molar ratio, solution pH, hydrothermal temperature, and reaction time. In comparison with Tar2− , Mal2− induced the direct crystallization of h-YPO4 microprismatic crystals while Suc2− restricted the 1-D growth of t-YPO4 nanocrystals. For the samples calcined at 700 °C, the down-conversion photoluminescence of Eu3+ in h-YPO4 and t-YPO4 and the up-conversion luminescence of the (Yb/Er)3+ couple in t-YPO4 were also comparatively studied and elucidated in detail. [ABSTRACT FROM AUTHOR]- Published
- 2017
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