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un Kyoung Yang, Byung Kee Moon, Byung Chun Choi, and Jung Hyun Jeonga) Department of Physics, Pukyong National University, Busan 608-737, Korea

Kwang Ho Kim School of Materials Science and Engineering, Pusan National University, Busan 609-735, Korea (Received 28 June 2012; accepted 30 August 2012)

Through a polyethylene-glycol-assisted hydrothermal method, a series of potassium fluoride (KF)–Yttrium (III) fluoride (YF3) system materials have been synthesized. By controlling the reactant ratios of KF: rare earth ions (RE31), the hydrothermal temperatures, and the pH values of the prepared solutions, the final products can evolve among the orthorhombic phase of YF3 and/or the tetragonal phase of potassium triyttrium decafluoride (KY3F10) and/or the cubic phase of potassium yttrium tetrafluoride (KYF4). The final products are characterized by the x-ray diffraction (XRD) patterns, the field-emission scanning electron microscopy (FE-SEM) images, the energy-dispersive spectroscopy (EDS) patterns, the photoluminescence (PL) spectra, and the luminescent dynamic decay curves. The XRD patterns of the samples suggest the phase evolution of the final products. The FE-SEM images and the EDS patterns prove that. Europium ion (Eu31) acting as a probe, its PL spectra and the luminescent decay curves all put together prove the phase evolution of the final products. The research can be extended to study the other KF–REF3 system materials.

I. INTRODUCTION

Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2012.331

tetrafluoride (LiGdF4) is an outstanding host for downconversion luminescence, for which the quantum efficiency is close to 200%.14 Rare-earth-doped single crystals of KYF4 are excellent solid-state laser materials, and laser action has been observed for ytterbium ions (Yb31), thulium ions (Tm31), and holmium ions (Ho31) in the KYF4 lattice.15,16 Recently, due to both their structural and optical properties, the RE31-doped KF–REF3 (RE 5 Y, Gd) system materials have received more and more attention.17–23 In the present article, we will research the synthesis, phase evolution, and optical properties of europium ion (Eu31)-doped KF–YF3 system materials. In recent years, materials scientists have explored various synthetic strategies for the syntheses of reproducible and controllable nanocrystals with uniform size, morphology, and chemical composition. Dramatic efforts have been dedicated to synthesize rare earth fluoride nano-/microcrystals with uniform size and shape. In particular, high quality, such as monodisperse, single-crystalline, well-shaped, and phase-pure fluoride nanocrystals have been fabricated successfully due to their potential applications in biology and medicine. There are several successful methodologies for preparation of fluorides that have been well reviewed by Lin.4 The hydrothermal treatment as a typical solution approach has been proved to be effective and convenient in preparing various inorganic materials with diverse controllable morphologies and architectures.24 Especially,