Effect of AlF3 and KF addition on the structure and luminescent properties of P2O5 – K2O – Nb2O5 – Bi2O3 glasses doped with Eu3+

Based on the developed phosphate glasses P₂O₅–K₂O–Bi₂O₃–Nb₂O₅ doped with Eu³⁺, the influence of AlF₃ and KF on the structural and luminescent properties was investigated. For this purpose, three series of glasses containing from 5 to 15 mol% fluorides were synthesized. Two of the series included the KF additive, which was introduced in two ways - proportionally and disproportionately at the expense of the K₂O share. The structural characterization (XRD, FTIR) allowed us to determine the evolution of the internal structure of the glasses caused by changes in the type and content of the introduced additives and the presence of the Eu dopant. Similarly, using DSC/DTA, the thermal properties of undoped matrices were defined. The luminescence enhancement caused by the addition of ≥10 mol% fluorides was confirmed by the obtained fluorescence spectra. The presented studies not only expand the state of knowledge about the effects of fluorides on phosphate glasses but also demonstrate the ease of obtaining materials with improved properties suitable for use as phosphor in LEDs.