Synthesis and electro-optical properties of spiro-bifluorenylvinylene-based polymers for light-emitting diodes applications

Abstract

Five new thermally robust electroluminescent arylenevinylene conjugated polymers, including poly[3′,6′-bis(3,7-dimethyloctyloxy)-9,9′-spirobifluorenyl-2,7-vinylene] [(OC₁₀)₂-Spiro-PFV] and poly[{3′,6′-bis(3,7-dimethyloctyloxy)-9,9′-spirobifluorenyl-2,7-vinylene}-co-2-{methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene}] [(OC₁₀)₂-Spiro-PFV-co-MEH-PPV], were synthesized and used to fabricate efficient light-emitting diodes (LEDs). The glass transition temperatures of the polymers were found to be higher than those of PPVs and PFs, and are in the range 170–222 °C. ITO/PEDOT/Polymer/LiF/Al LEDs containing the new polymers were found to have emission colors that vary from blue (467 nm) to yellow (587 nm) depending on the copolymer composition. The maximum brightness and luminance efficiency of these LEDs were found to be up to 4062 cd m⁻² and 1.79 cd A⁻¹ respectively.