Energy transfer and multicolour tunable emission of Eu,Tb(PSA)Phen composites

A series of new photoluminescent composites containing Eu3+ and Tb3+ were synthetized by using two different ligands: poly(sodium acrylate) (PSA) - used as a polymeric matrix - and 1,10-phenthroline (Phen) as a co-ligand. Furthermore, composites containing both lanthanide ions Eu3+ and Tb3+ were also prepared. The composites show excellent luminescent properties with characteristic red and green emission from Eu3+ and Tb3+, respectively, due to the "antenna effect" promoted by Phen. The composites were characterized by Fourier transform infrared spectroscopy (FT-IR), TGA and SEM-EDS. It can be observed, by UV–vis and photoluminescence studies, that in Eu,Tb(PSA)Phen composites, the energy transfer (ET) process occurs from Tb3+ to Eu3+, and the ET efficiency is found to be ca. 46% in the evaluated concentration range. Finally, the emitted color from Eu,Tb(PSA)Phen composites can be tuned from green, to orange and red (passing through yellow) simply by changing the Eu3+/Tb3+ molar ratio. All these results suggest that the composites possess potential application as luminescent compounds for the development of sensing materials.