Energy transfer processes between rare earth ions and white light emission in inorganic glasses

In this paper, lead borate glasses singly, doubly and triply doped with rare earth ions were investigated using optical spectroscopy. Luminescence spectra of rare earths were detected under various excitation wavelengths. The main green luminescence band related to
⁵
D
₄
→
⁷
F
₅
transition of Tb
³⁺
is observed under excitation of Dy
³⁺
. The main red emission band due to
⁵
D
₀
→
⁷
F
₂
transition of Eu
³⁺
is well observed under direct excitation of Tb
³⁺
. In both cases, the energy transfer processes from Dy
³⁺
to Tb
³⁺
and from Tb
³⁺
to Eu
³⁺
in lead borate glasses occur. Lead borate glass triply doped with trivalent rare earths exhibits nearly white light emission originating from the simultaneous generation of several bands of Dy
³⁺
, Tb
³⁺
and Eu
³⁺
ions under selective UV-visible excitation.