K3Y3-xEux(BO3)4 형광체의 Eu 형광 농도 의존성 연구

Abstract

A study on concentration dependence of Eu3+ luminescence in K3Y3-xEux(BO3)4

Roh Il Hoon

Department of Physics Pukyong National University

Abstract Red-emitting phosphors of Eu3+-doped K3Y3-xEux(BO3)4 were prepared by solid-state reaction method. The excitation and emission spectra and decay curves of K3Y3-xEux(BO3)4 (x =0.01, 0.01, 0.1, 1.0, 5.0, 10, 30, 50, 80, 100 mol%) are investigated by the optical and site–selective laser-excitation spectroscopy at room temperature. The X-ray powder diffraction was used to analyze the structural characteristics. The excitation spectrum of the Eu3+ luminescence in K3Y3-xEux(BO3)4 was measured by monitoring the emission at 612 nm. The charge transfer band is observed in the wavelength region 250-350 nm. The sharp excitation lines in the wavelength region 350-470 nm are attributed to the transitions from ground 7F0 level to the excited 5DJ (J=0, 1, 2, and 3), 5H7, 5L7, and 5L6 levels. The strongest excitation line is observed at 396 nm due to the 7F0 → 5L6 transition. Emission spectrum shows the lines at around 590 and 612 nm corresponding to the 5D0→ 7F1 and 5D0→ 7F2 transitions The emission intensity increases with increasing Eu3+-concentration up to 50 mol% and then luminescence quenching occurs at higher Eu3+ concentration. Two different crystallographic sites corresponding to two Y3+ sites are identified from the excitation spectra of the 7F0 → 5D0 transition in K3Y3-xEux(BO3)4