YBO3:Ce3+,Tb3+ phosphor was prepared from rare earth oxides and boric acid by a solid state reaction. The phosphor absorbs near UV light through 4f-5d transitions of Ce3+, followed by broad emissions through 5d-4f transitions of Ce3+ and sharp emissions through 4f-4f transitions of Tb3+. Spectroscopic investigations for samples with various Ce3+ and Tb3+ concentrations reveal nonradiative energy transfer from Ce3+ to Tb3+. Emission color of the YBO3:Ce3+,Tb3+ varies from blue (0.163, 0.019) to green (0.321, 0.585) depending on the Ce3+ and Tb3+ concentrations. The optimized green-emitting Y 0.82Ce0.03Tb0.15BO3 phosphor has an emission color of (0.309, 0.547) with an external quantum efficiency of 76.7%. The photoluminescence intensity of this phosphor at 150°C keeps 87% of its intensity at room temperature, showing sufficient thermal stability for white light emitting diode applications.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials