Intense visible fluorescence and energy transfer in Dy³⁺, Tb³⁺, Sm³⁺ and Eu³⁺ doped rare-earth borate glasses

Tb³⁺/Dy³⁺ and Eu³⁺/Sm³⁺ doped rare-earth borate glasses have been synthesized and characterized. Under UV excitation, Dy³⁺, Tb³⁺, Sm³⁺ and Eu ³⁺ emit intense yellowish white, green, reddish orange and red lights, respectively. In Tb³⁺/Dy³⁺ co-doped glasses, the enhancement of Tb³⁺ green emission is observed, and the sensitization is related to the efficient energy transfer from Dy³⁺ to Tb ³⁺. In Eu³⁺/Sm³⁺ co-doped glasses, the excitation wavelength range of Eu³⁺ emission is broadened owing to the energy transfer from Sm³⁺ to Eu³⁺. This broadening makes the Ar⁺ 488 nm wavelength laser a powerful excitation source for Eu³⁺ fluorescence. The rare-earth doped glasses with various visible emissions are useful for developing new color light sources, fluorescent display devices, UV-sensor and tunable visible lasers.