희토류 이온(Er/Yb)이 도핑된 LaPO 4 나노입자의 합성과 발광특성

Abstract

Due to the luminescence by Er 3+ activator, Er-doped LaPO 4 powders can be applied for optical amplification materials. In this study, LaPO 4 :Er nanoparticles were synthesized in solution system using a high-boiling coordinating solvent and their properties were investigated through various spectroscopic techniques. The nanoparticles were to take a single phase of monazite structure by a X-ray diffraction analysis and to have the 5-6 nm of particles size with narrow size distribution by a TEM. And it was confirmed by the EA and FT-IR analyses that the surfaces of nanoparticles are coordinated with the solvent molecules, which will possibly keep from agglomerating between LaPO 4 :Er nanoparticles. In the emission spectrum of LaPO 4 :Er nanoparticle at NIR region, on the other hand, it was measured that the emission intensity is very weak, which is due to the transition from 4 I (13/2) to 4 I (15/2) of Er 3+ ion. It was interpreted that the weak luminescence of LaPO 4 :Er is originated from the hydroxyl groups adsorbed on the surfaces of the nanoparticles, because OH group acts as an efficient quencher for the 4 I (13/2) \longrightarrow 4 I (15/2) emission of Er 3+ activator. But the co-doping of Yb 3+ as a sensitizer in this nanoparticle results in the increase of the emission intensity at 1539 nm due to the effective energy transfer from Yb 3+ to Er 3+ . In addition, the synthesized nanoparticles exhibited good dispersibility with some polymers and effective luminescence at NIR region.n.