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

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 degrees 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.