In this paper, we propose for the first time that the combination of a sol-gel
derived diurethane cross-linked siloxane-based biohybrid host including short poly(
-caprolactone) segments (PCL(530)) andlanthani
de aquocomplexes incorporating
-diketonate ligands yields an effective protecting cage thatefficiently encapsulates the emitting centers and reduces luminescence quenching. The results obtainedusing the Eu(tta)
3(H
2O)
2 (where tta
- is 2-thenoyltrifluoracetonate) complex
demonstrate that 1 (2) carbonyloxygen atoms of the host matrix enter the Eu
3+ coordination shell, thus replacing the labile water molecule(s). The significant increase in the quantum efficiency
q of the doped hybrid with respect to that ofEu(tta)
3(H
2O)
2 (44.2 versus 29.0%, respectively) reveals that complex anchoring to the PCL(530)-basedhost structure contributes to enhancement of the
5D
0 quantum efficiency. However, when a complex thatcontains only strong chelating ligands, such as Eu(tta)
3phen (where phen is 1,10-phenantroline), isincorporated into the same host medium, the effect is
lost and the
5D
0 nonradiative paths in the dopedhybrid are higher than those existing in the complex itself. Un
der UVA exposure, the emission intensityof PCL(530)/siloxane/Eu(tta)
3(H
2O)
2 decreased 10% in 11 h, whereas that of PCL(530)/siloxane/Eu(tta)
3phen
decreased 25% in the same period of time.