Synthesis and characterization of spirobifluorene-based polymers for organic light-emitting diode applications

Abstract

The following series of blue EL polymers was synthesized using the Suzuki polymerization method: poly(3′,6′-bis(3,7-dimethyloctyloxy)-9,9′-spirobifluorene-2,7-diyl) poly[(OC10)2-spirobifluorene], poly(3′,6′-bis(3,7-dimethyloctyloxy)-9,9′-2,7-diyl-co-4-(3,7-dimethyloctyloxy) phenyl-diphenylamine-4′,4′-diyl} poly[(OC10)2-spirobifluorene-TPA] (5∶1, 9∶1) and poly(3′,6′-bis(3,7-dimethyloctyloxy)-9′,9′-spirobifluorene-2,7-diyl-co-4-(6-((3-methyloxetan-3-yl)methoxy) hexyloxyphenyl-bisphenylamine-4′,4′-diyl) poly[(OC10)2-spirobifluorene-TPA-oxetane]. The weight average molecular weight (Mw) and polydispersity of the resulting polymers ranged from 1.6×104–1.5×105 and 1.77–2.31, respectively. The resulting polymers were completely soluble in common organic solvents and were easily spin-coated onto an indium tin oxide (ITO) substrate. The polymers exhibited strong blue emission peaking at 450 nm. The maximum brightness and luminance efficiency were 9,960 cd/m2 and 1.2 cd/A, respectively.