Synthesis and characterization of new polyfluorene derivatives

Abstract

Polyfluorene derivatives, PFDTPAs, including a triphenylamine moiety as a side chain were synthesized through Ni(0) mediated random copolymerization using fluorene and triphenylamine substituted phenyl monomers. All synthesized copolymers exhibited the similar absorption and photoluminescence (PL) maxima at about 388 nm and 414 nm in $CHCl_3$ solution, respectively. The maxima of the absorption and PL emission on the polymer films were appeared at ca. 381 nm and 474 nm, respectively. Polymer light-emitting diode (LED) devices were fabricated as an ITO/PEDOT/polymer (PFDTPA)/LiF/Al configuration. The electroluminescence (EL) emission maxima of the copolymers were gradually shifted to the long wavelength regions and EL quantum efficiencies of the PFDTPAs increased as the triphenylamine ratio increases. On the other hand, the threshold voltages of PFDTPAs LED devices were decreased, and brightness was increased as the content of triphenylamine moiety increases.