Photoluminescence properties of Tm³⁺/Tb³⁺/Sm³⁺tri-doped Na₅Y₉F₃₂single crystal with high thermal stability for white light-emitting diodes

Yang Qiao¹，Xiong Zhou¹，Jianli Zhang¹，Haiping Xia¹，Hongwei Song²，Baojiu Chen³

1. Key Laboratory of Photo-electronic Materials,Ningbo University2. State Key Laboratory on Integrated Optoelectronics,College of Electronic Science and Engineering and College of Physics,Jilin University3. Department of Physics,Dalian Maritime University

摘 要：A novel Tm³⁺/Tb³⁺/Sm³⁺tri-doped Na₅ Y₉ F₃₂ single crystal was synthesized by a modified Bridgman method for the propose of white light emitting diodes.The fluorescence spectra of various Sm³⁺ion concentrations and fixed 0.4 mol% Tm³⁺ and 0.5 mol% Tb³⁺ were measured and studied systematically excited by near-ultraviolet light of 355 nm.The Sm3+ion concentration takes apparent effect on the relative intensity of peaks in the visible region and the color coordinate combining from these emission bands.A near pure white light emission with color coordinates（0.3295,0.3057） and color temperature（5657 K） can be obtained when the concentrations of Tm³⁺,Tb³⁺ and Sm³⁺ ions are 0.4 mol%,0.5 mol%and 0.8 mol%,respectively.Furthermore,the practical down-conversion internal quantum yield was measured by integrating spheres at about 14.39%.The tri-doped Na₅ Y₉ F₃₂ single crystal shows a high thermal stability inferring from the temperature dependent emission in which the integrated emission intensities are reduced only by～3% with the increase of temperature from 280 to 450 K.The present results demonstrate that the Tm³⁺/Tb³⁺/Sm³⁺tri-doped Na₅ Y₉ F₃₂ single crystal may provide a promising candidate for white light-emitting diodes,luminescent materials and fluorescent display devices.

关键词：