Synthesis and Optoelectronic Properties of Conjugated Phosphorescent Copolyfluorenes Containing Iridium Complexes in Main Chains and Light-Emitting Diodes Formed on Their Basis

New copolyfluorenes containing covalently bound iridium β-diketonate complexes (featuring high values of phosphorescence efficiency) in the backbone are synthesized through the targeted selection of molar ratios of monomers containing functional groups responsible for various irradiation regions under conditions of the Yamamoto reaction. All copolymers show solubility in organic solvents, such as DMF, DMAA, DMSO, toluene, THF, and chloroform, and feature reversible redox electrochemical properties. The electroluminescence spectra of the copolymers show broad intense bands in the visible region with maxima at 482–538 nm and a maximum brightness of 320 cd/m2 at a current density of 2900 A/m2. The iridium-containing copolyfluorenes are of interest as effective electroluminescent materials for light-emitting diodes.