Synthesis and characterization of high triplet energy polyfluorene bearing m-tetraphenylsilane segment as a polymer host for green phosphorescent polymer light emitting diodes

• 2,7-Fluorene and m-tetraphenylsilane moieties in the polymer backbone.
• m-Tetraphenylsilane can interrupt the π-conjugated length.
• m-Tetraphenylsilane increased triplet energy level and optical band gap.
• m-Tetraphenylsilane improved device performances of poly(2,7-fluorene)s.

A high triplet energy (ET) copolymer P2SiF, derived from 2,7-fluorene and m-tetraphenylsilane segment, was synthesized as a green host for green phosphorescent polymer light emitting diodes. The photophysical properties and device performances of P2SiF were studied and compared with previous P1SiF with 2,7-fluorene and p-tetraphenylsilane segment. P2SiF depicted a higher triplet energy level up of 2.60 eV than that of P1SiF, which was probably one of the highest triplet energy from the conjugated polymers with poly(2,7-fluorene) structure. While doped with a green phosphor tris[2-(p-tolyl)pyridine]iridium [Ir(mppy)3], the device hosted by P2SiF showed better performance with a maximum efficiency of 3.36 cd/A as low as doped concentration of 4 wt% Ir(mppy)3.