Enhancement of photoluminescence in various Eu x Re(1−x)TTA3Phen (Re = Y, Tb) complexes molecularly doped in PMMA

Abstract

Europium β-diketonate complexes Eu x Re(1−x)(TTA)3Phen, (Re = Y/Tb, TTA: thenoyl trifluro acetone, Phen: 1–10 Phenanthroline; x = 0.5) have been molecularly doped in poly methyl methacrylate matrix to study the concentration effect on the optical properties such as optical absorption and photoluminescence spectra for four different amounts of weight % (10, 25, 50 and 60 %). All these doped complexes show strong absorption peaks at 334 and 280 nm attributed to n–π* and π–π* transitions of β-diketonate ligand TTA respectively. The close absorptivity of all the complexes is due to the same tris chelated core TTA. Among the three complexes doped in PMMA matrix Eu0.5Tb0.5(TTA)3Phen complex shows hyper chromic shift with enhancement in the luminescent intensity. Enhancement of red light emission have been observed with the increase in wt% of all pure and doped systems in the order of Eu(TTA)3Phen, 25 > 50–60 %. However the luminescence intensity of these blended films with 50 and 60 % of rare earth complexes shows nearly equal value, indicating that the optimal doping concentration is about 50 % under the chosen experimental conditions. Hence these complexes are best suitable in fabricating eco-friendly organic light-emitting devices and displays by solution techniques, which can be operated at very low voltage.