Luminescent properties of Eu²⁺ doped borosilicate glasses

During the recent decade's years, the luminescence properties of divalent europium have attracted more and more interest for its wide emission spectrum ranging from blue to blue-green. As for the rare earth optical glasses, the rare earth ion dopants with high brightness and stable performance are always the important point, and Eu²⁺ doped borosilicate glasses also have these properties. Herein, by using the high-temperature solid-phase synthesis method, a typical blue borosilicate glass named MgO · SiO₂ · B₂O₃:Eu²⁺ was synthesized. The influence of different Eu²⁺ doped concentrations on the luminescent properties of borosilicate glass was studied. X-ray diffraction and luminescence spectroscopy were used to characterize this glass samples. Excited by the UV light, the emission spectrum of the glass phosphor consists of two bands, peaking at about 460 nm and 500 nm, which are attributed to the covalence property of the Eu-O bond and the different coordination environments around the Eu²⁺ ions in the host lattice. The energy transfer process is accompanied by the loss of energy. In addition, with the concentration of divalent europium ions increasing, fluorescence quenching occurred, so emission intensity of the 500 nm emission band is weaken. The glass phosphor has strong excitation at around 300~440 nm and emitted a typical bright blue luminescence. And with the mole fraction of doped Eu²⁺ increasing, the peak of emission spectrum shows a red shift, and the intensity remarkably decreased. Thus it could have applications as a blue component in solid-state lighting devices assembled by near-UV light emitting diodes (LED) and with tricolor phosphors.