Structure, tunable luminescence and energy transfer in Tb 3+ and Eu 3+ codoped Ba 3 InB 9 O 18 phosphors

Abstract

The borate Ba 3 InB 9 O 18 (BIBO) is a promising host material for phosphors. A series of Tb 3+ and Eu 3+ codoped Ba 3 InB 9 O 18 phosphors were synthesized. Based on the Rietveld method, structure refinement of the codoped BIBO phosphor was carried out. Then, the luminescence properties of BIBO:Tb 3+ , Eu 3+ phosphors were extensively investigated under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation. The measured PL spectra and decay times evidenced that energy transfer occurs between the Tb 3+ and Eu 3+ ions. The energy-transfer mechanism from Tb 3+ to Eu 3+ in Ba 3 InB 9 O 18 is dominated by electric multipolar interactions, with the critical distance calculated to be 10.97 Å. The temperature sensitivity of the Tb 3+ and Eu 3+ codoped sample under VUV was also investigated at the low temperature range from 25 K to 298 K. The emission color could be tuned from green to the red region by adjusting the concentration of codoped ions. The results indicate that the BIBO-based phosphors are valuable candidates for applications in the display and lighting fields.