3-Phenyl-4-acyl-5-isoxazolonate complex of Tb3+ doped into poly-beta-hydroxybutyrate matrix as a promising light-conversion molecular device

Abstract

A novel class of efficient antenna complexes of Tb3+ based on the use of 3-phenyl-4-acyl-5-isoxazolone ligands has been designed, synthesized, characterized and their photophysical properties evaluated. The new heterocyclic beta-diketonate complexes of Tb3+ exhibit high green luminescence efficiency in the solid state with quantum yields between 59-72%. Furthermore in this work, the synthesis, characterization and luminescent properties of poly-beta-hydroxybutyrate (PHB) polymer films doped with Tb3+-3-phenyl-4-acyl-5-isoxazolonate complexes at 5, 10, 15 and 20% (mass) are reported. The fact that the luminescent efficiency of doped films is enhanced (quantum yields between 74-86%) compared with precursor samples revealed that the polymer matrix acts as a co-sensitizer for Tb3+ centers. The luminescence intensity decreases, however, with increasing precursor concentration in the doped PHB to greater than 15% where a saturation effect is observed, indicating that changes in the polymer matrix improve the absorption properties of the film, consequently quenching the luminescent effect. Synthesized luminescent polymers containing Tb3+-hetrocyclic beta-diketonate complexes showed promising photoluminescence efficiency for applications to polymer light-emitting diodes and active polymer optical fibers.