16 - Metal organic framework of Eu(dmh)3phen polymer matrices and their applications for energy-efficient solution-processed OLEDs

Abstract

We account the metal organic framework of europium-activated hybrid organic Eu(dmh)3phen [Eu: europium; dmh=2,6-Dimethyl-3,5-heptanedione; Phen: 1,10 Phenanthroline] complex into host polymers, polymethylmethacrylate (PMMA), and polysterene (PS) at different wt% of the complex by molecular doping. The photophysical properties of these films were characterized by ultraviolet (UV)-Vis absorption and photoluminescence (PL) spectroscopy. Absorption spectra were employed to study the spectral shift of π→π* and n→π* transitions in solid state at different wt% and the films solvated in various organic solvents at different concentrations. The optical energy band gap of the films in PMMA/PS was found to be in the range of 3.5–4.0eV. The PL emission spectra always registered at 613nm, irrespective of polymer wt% and basic/acidic environment. Relative intensity ratio (R), which quantifies the degree of Eu3+ symmetry variation in diverse local environments, was illustrated. The Commission International Eclairage (CIE) coordinates of Eu(dmh)3phen blended thin films with PMMA and PS in various organic solvents at 10 and 25wt% were found to be in the orange–red region irrespective of doping concentration and solvent polarity. Thus, the synthesized complex proves its perspective as red light emissive material for OLED devices that can be fabricated by affordable solution techniques.