Radiative Emission at Mid‐Infrared Wavelengths from Rare‐Earth Ions Via Nanocrystal Formation in Oxyfluoride Glasses

Abstract

We observed experimentally that the formation of β‐PbF2 nanocrystals (NC) in oxyfluoride glass conspicuously altered the local structures of rare‐earth (RE) ions, which then enabled their intra4f‐configurational transitions to be luminuous even at mid‐infrared (MIR) wavelengths. Radiative emission centered at ∼2.87 μm originating from Dy3+:6H13/2→6H15/2 transition was remarkably enhanced after the NC were formed by thermal treatment in an ambient atmosphere. However, emission intensities due to Er3+:4I11/2→4I13/2 and Ho3+:5I6→5I7 transitions turned out to be less dependent on the NC formation, which indicated that the enhancement of MIR emission depended on RE.

Eu2+/Eu3+-doped oxyfluoride glass ceramics with LaF3 for white LED color conversion

“…4, when the glass was heat treated at 750°C for varying duration times up to 40 h, the overall emission intensity is highly improved. The emission intensity change can be attributed to a local environment change, from oxygen-dominated to fluorine-dominated structure, induced by the formation of fluoride nano-crystals within the glass matrix, as previously reported [10,20]. XRD was used to examine the glasses and characteristic LaF 3 crystal diffraction patterns were observed when the glasses were heat treated (Fig.…”