Charge Transport and Sensitized 1.5 μm Electroluminescence Properties of Full Solution-Processed NIR-OLED based on Novel Er(III) Fluorinated β‑Diketonate Ternary Complex

Abstract

Solution-processed near-infrared organic light-emitting diodes (NIR-OLEDs) with structure glass/indium–tin oxide/poly­(3,4-ethylenedioxythiophene)-poly­(styrene sulfonate)/Er-complex/Ca/Al based on a novel Er­(III) complex, [Er­(tfnb)₃(bipy)] (Htfnb = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione and bipy = 2,2′-bipyridine) have been manufactured and their properties have been studied. A complete quenching of the organic ligand visible emission is shown, and only the sensitized 1.5 μm electroluminesce from Er­(III) results. From the electrical characteristic we present the mobility dependence on applied voltage using a numerical model, comparing it to poly­(9,9-dioctylfluorene), a commercial semiconducting polymer with optical properties close to those of the molecular ligands. The synthesis of the novel complex together with a detailed analysis of its structure elucidated by XRD, ¹H NMR, Raman, and Fourier-transform infrared spectroscopies is presented. A wide-ranging characterization of its photophysical properties in terms of absorption and steady and transient photoluminescence is used to investigate the energy-transfer process from the organic ligand to the central Er­(III) ion