Eu3 +-activated B2O3–GeO2–RE2O3 (RE = Y3 +, La3 + and Gd3 +) borogermanate scintillating glasses

• Gd2O3 is one of the most important agents to design dense scintillating materials.
• The convalency of RE–O derived from Judd-Ofelt analysis may be associated with the glass stability.
• The RE–O convalency is also an indicator for the temperature dependence of Eu3 + emission.

Borogermanate scintillating glasses with composition of 25B2O3–40GeO2–2Eu2O3–33RE2O3 (RE = Y, La and Gd) were synthesized by melt-quenching method. The effect of RE2O3 on the glass structure and performance including the density, transmittance as well as luminescent properties under both ultraviolet (UV) and X-ray excitation were compared and studied systematically. The enhanced intensity of Eu3 + emission under X-ray excitation is remarkably higher than that under UV excitation. The temperature-dependent emission spectra in the 75–295 K temperature region reveal that the thermal quenching behavior of Eu3 + luminescence in Y2O3-based glass is slightly better than that in La2O3- or Gd2O3-based one. The covalency property of EuO bond and the local environment of Eu3 + ions is evaluated by the values of Ωt parameter by employing the Judd–Ofelt analysis. The possible interconnection among the covalency nature of EuO bond, the thermal quenching behavior of Eu3 + emission, and the thermal stability of the designed borogermanate scintillating is also discussed.