Structural and optical properties of Cr3+ embedded in a P2O5-B2O3-ZnO-BaF2-AlF3 fluoroborophosphate glasses

A new fluoroborophosphate glass doped with different amount of CrF3 were prepared via the melt-quenching method. These glasses were characterized by several techniques. The amorphous nature of the glass was evidenced by X-ray diffraction. Raman and FTIR were used to determine the functional groups composing the glass network. It was demonstrated the formation of B-O-P bond which replace some of the P-O-P bond and ensure the bonding of phosphorus and boron groups. Electron paramagnetic resonance (EPR), optical absorption and photoluminescence (PL) investigation have shown that Cr3+ ions have a preference to be located at weak field with distorted octahedral sites and they are mainly dispersed in phosphorus rich environment with fluorine or mixed fluorine/oxygen surrounding anions. Cr3+ sites dispersion was also evidenced by analyzing the temperature dependence of the PL spectra and the PL decay.