Tb3+ 이온이 첨가된 La2(WO4)3 형광체의 합성과 분광학 연구

Abstract

Tb3+-doped La2(WO4)3 phosphors were synthesized by using solid-state reaction at high temperature in the air atmosphere. The formation of single phase La2(WO4)3 and Tb2(WO4)3 were confirmed by X-ray powder diffraction analysis. The emission and excitation spectra of La2(WO4)3:Tb3+ were measured at room temperature under the UV excitation and it is found that the spectra depend strongly on Tb3+ - concentration in La2(WO4)3:Tb3+. The sharp lines due to the 4f - 4f transition of Tb3+ in La2(WO4)3 are observed in the wavelength region 320 – 380 nm. The broad band is ascribed to the 4f – 5d transition of Tb3+ centered at 266 nm. The assignments of the Tb3+ 4f8 configuration in La2(WO4)3 are performed with the excitation and emission. By increasing Tb3+-concentration, the luminescence quenching is observed at 70 mol% of Tb3+. The energy transfer process is investigated in La2(WO4)3:Tb3+ by time-resolved spectroscopy in which an efficient energy transfer occurs from WO43- to Tb3+.