Lanthanide based emitters as quantum light sources

In recent years, research has focused on optimizing light sources for use in the latest technology optical devices, such as linear photonic integrated circuits and telecom optical fibers. Recently, quantum photonics is becoming increasingly popular in view of the potentialities of single-photon emitters and entangled photons in data communication and security. In this framework, luminescent lanthanide ions offer a promising alternative to current quantum light sources based on inorganic bulk materials, in view of the long-lived and highly coherent emission provided by intra-shell f-f transitions. These ions can be combined with suitable organic ligands able to behave as antennas, that is, they absorb light, transfer the absorbed energy to the metal via an intersystem crossing process and induce enhanced sensitized lanthanide emission. In this work, we investigate novel lanthanide-based complexes to be proposed as flexible quantum light sources. Tripodal benzimidazole[1] organic ligands derivatives have been reacted with lanthanide ions (Eu, Tb, Sm, Er, Yb, Nd, Gd), to afford highly crystalline materials showing luminescent properties in the visible and near-infrared spectral ranges. The correlation between the observed emission and the geometry and symmetry of the compounds is investigated. This research is performed in the framework of the EIC Pathfinder Challenges "ARTEMIS " GA 101115149 and PRIN2022 PNRR “QuantaMol” Prot. P2022PKW4T projects.