Luminescent Eu/Tb-Based Amorphous MOF–Glass Composites

Amorphous metal–organic frameworks (aMOFs) and phosphate-based glasses are promising materials for developing hybrid luminescent composites. In this work, three amorphous MOFs (Zr/Eu-BTC, Zr/Tb-BTC and Zr/Eu/Tb-BTC) were synthesized and investigated alongside a low-T_g fluorophosphoniobate glass host. Comprehensive structural, thermal, and optical characterizations were performed. Excitation spectra of the co-doped aMOF confirmed an efficient Tb³⁺-to-Eu³⁺ energy transfer via a band at 488 nm. However, the most intense excitation occurred at 297 nm (π→π^* ligant transition), demonstrating a highly efficient antenna effect that sensitizes both lanthanide ions. By exciting into this ligand band, the emission profiles can be modulated by adjusting the Eu³⁺/Tb³⁺ ratio. These amorphous frameworks are currently being investigated for ratiometric thermometry and white-light-emitting applications.