Synthesis and electroluminescent properties of new amorphous cyclohexyl- and hexyl-substituted ter(9,9-dialkylfluorene)s

Abstract

A series of ter(9,9-dialkylfluorene)s (TFs) containing cyclohexyl and hexyl side groups has been synthesized via the Suzuki coupling reaction. Their chemical structures were characterized by (1)H NMR and (13)C NMR. All TFs were soluble in common organic solvents and showed good thermal stability up to 400 degrees C. In particular, T(CHC)F composed of two 9,9-bis(cyclohexylmethyl)fluorenes and one dihexylfluorene showed improved thermal stability over T(HHH)F and was found to be amorphous, unlikely with T(CCC)F. A light-emitting diode device fabricated with an ITO/2-TNATA/NPB/TFs/Alq3/Liq/Al configuration exhibited blue light emission with EL maxima at 450 nm and EL efficiency of 1.1 cd/A.