Synthesis and characterization of a novel electroluminescent polymer based on phenoxazine and fluorene derivatives

A new electroluminescent polymer was prepared by oxidative coupling copolymerization of N-(4-n-butylphenyl)phenoxazine (PPX) and 9,9-di-n-butylfluorene (DBF) using iron(III) chloride. The obtained polymers were soluble in common organic solvents and had number-average molecular weight as high as 10,000. The UV-vis absorption maximum and photoluminescence peak shifted to longer wavelengths with the increase of PPX content. The increase of PPX content also caused increase of hole mobility and decrease of electron mobility. A simple single-layer light-emitting-diode device having a structure of indium tin oxide/polymer/Ca/Al was fabricated. The polymer containing 30% of PPX unit showed highest electroluminescent properties with a maximum luminance of 1084 cd/m2 at 15.5 V operating voltage.