Synthesis and characterization of spiro-triphenylamine configured polyfluorene derivatives with improved hole injection

Abstract

We report on the synthesis of a spiro-fluorene derivative with bulky tert-butyl-substituted triphenylamine structure. The compound was synthesized in an attempt to enhance both hole injection and physical properties. A series of copolymers of the compound and a spiro-anthracenefluorene structure were synthesized, and their physical, optical, and electrochemical characteristics were investigated. The polymers showed good thermal stability with decomposition temperatures in excess of 389 degrees C and high glass transition temperatures in the range of 112-207 degrees C. The emission characteristics of the polymers were similar to that of dialkyl polyfluorenes. Cyclic voltametry studies revealed that the energy level of polymers can be tuned by adjusting the spiro-triphenylamine content with a tuning range of about 0.5 eV. Organic light-emitting diodes were fabricated using the polymers. All of the devices showed an emission in the deep blue region, and the copolymers showed improved hole injecting/transporting characteristics.