Work

Fluorine incorporation enhances red emission, radiative performance, and thermal stability in Eu3+-doped borophosphate glasses for solid-state lighting

Year: 2026

Type: article

Abstract: In this work, Eu 3+ -doped glasses based on the P 2 O 5 -B 2 O 3 -Al 2 O 3 -BaO/BaF 2 -Na 2 O system were prepared using the melt-quenching technique. The effects of fluorine substitution on the structural network, thermal stability, and optical response were systematically evaluated. FTIR and DTA measurements reveal that the introduction of fluorine reduces the connectivity of the glass network, accompanied by a drop in glass transition temperature from 477 ℃ to 470 ℃. Phonon sideband measurements reveal phonon energies of 1129 cm –1 and 1181 cm –1 for the fluorinated and non-fluorinated glasses, respectively, with a lower relative multi-phonon relaxation rate observed in the fluorine-containing sample. Under excitation at 394 nm, the red emission from the Eu 3+ -doped fluorinated glass is roughly 1.6 times stronger than that from its fluorine-free counterpart, and a fluorescence lifetime of 2.584 ms is recorded. All fabricated glasses exhibit correlated color temperatures between 2258 K and 2266 K, color purity values approaching unity, and chromaticity coordinates closely matching the NTSC standard (0.67, 0.33). When heated to near 150 ℃, the fluorinated glass retains about 94% of its initial emission intensity. Judd-Ofelt analysis further indicates that fluorine incorporation enhances the covalency between Eu 3+ and O 2– ions. The fluorinated glass also shows promising radiative characteristics, including a radiative branching ratio of 65.39%, a stimulated emission cross-section of 11.17 × 10 –22 cm 2 , and a gain bandwidth of 11.17 × 10 –28 cm 3 , suggesting its viability as a high-gain laser medium. These findings point to the strong potential of Eu 3+ -doped fluoroborophosphate glass for use in solid-state lighting and laser devices.

Source: Journal of Alloys and Compounds

DOI: 10.1016/j.jallcom.2026.191160