Unusual Eu 3+ Luminescent Properties in Alkaline Lanthanum Fluorogermanate Glasses and Glass–Ceramics
Year: 2026
Type: article
Abstract: ABSTRACT Lanthanum fluorogermanate glass samples were prepared by melt‐quenching in ternary compositions 55GeO 2 –15M 2 O–30LaF 3 , M being K or Na and doped with 0.25 mol% of Eu 2 O 3 . Thermal analysis by differential scanning calorimetry (DSC) technique allowed us to determine both glass transition and crystallization temperatures in bulk and powder samples. Heat treatments (HTs) were performed on the basis of DSC curves with increasing HT time and temperature, and glass–ceramics were obtained in both systems. In the potassium‐based glass composition, cubic KLaF 4 is precipitated for lower HT temperatures. However, for the sodium‐based glass, hexagonal NaLaF 4 is first precipitated at lower temperatures, whereas hexagonal fluorecite LaF 3 is also crystallized at higher temperatures. Eu 3+ spectroscopy identified strong emission dependency with the crystallization state and nature of crystalline phases. Emission bands related to electronic transitions from the 5 D 2 and 5 D 1 , usually not observed in oxide and even oxyfluoride glasses, were clearly identified and with relative strong intensity together with the well‐known Eu 3+ red emissions, pointing out unusual effective Eu 3+ blue and green emission in these glass–ceramics. Experimental lifetimes were useful to identify different Eu 3+ sites related with oxide/fluoride as well as glassy/crystalline environments.
DOI: 10.1111/jace.71392
Language: English
Subfield: Ceramics and Composites
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: Fundação de Amparo à Pesquisa do Estado de São Paulo, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Financiadora de Estudos e Projetos, Fundação de Amparo à Pesquisa do Estado de Minas Gerais, Fundação de Amparo à Pesquisa do Estado de Goiás
OpenAlex ID: W7140176680