Study on luminescence properties of Tm3+/Tb3+/Eu3+ doped germanosilicate glass

In this paper, Tm ³⁺/Tb ³⁺/Eu ³⁺ co-doped germanosilicate glass was prepared by high temperature melting method. The luminescence properties of the glass samples were characterized by X-ray diffraction, excitation and emission spectra, fluorescence lifetime and CIE chromaticity diagram. The density was measured and the distance between rare earth ions was calculated. The energy transfer method between Tm ³⁺/Tb ³⁺/Eu ³⁺ is described in detail by Dexter theory. The results show that Tm ³⁺ transfers energy to Tb ³⁺. Tm ³⁺ transfers energy to Eu ³⁺ and the transfer mechanism is electric dipole-quadrupole transmission. Tb ³⁺ transfers energy to Eu ³⁺ in a electric quadrupole-quadrupole mechanism. The CIE chromaticity diagram shows that the prepared glasses are all in the white light range when the excitation wavelength is 359 nm, realizing the tunability from cool white light to warm white light.