Syntheses and Characterization of Electroactive and Photoactive 2,7-Carbazolenevinylene-Based Conjugated Oligomers and Polymers

This study reports the first syntheses and characterization of 2,7-carbazolenevinylene-based oligomers and polymers. Their relatively straightforward syntheses are mainly based on Horner-Emmons or Knoevenagel coupling reaction leading to well-defined oligomers and polymers. As expected, introduction of vinylene and cyanovinylene unit into the polymer backbone decreases the band gap allowing a fine-tuning of the optical and electrical properties. These electroactive and photoactive organic materials exhibit promising performances in light-emitting devices and field-effect transistors. For instance, preliminary measurements using poly (N-(2-ethylhexyl)-2,7-carbazolenecyanovinylene-alt-2,5-dioctyloxy-1,4-phenylenevinylene) (PCCVP) have revealed orange-red emission with an intensity of 245 cd/m^2 at 10 V, whereas p-type mobility of about 3.7 × 10^-2 cm^2/V·s and an on/off ratio as high as 106 were reached with 1,4-bis(vinylene-(N-hexyl-2-carbazole)) phenylene (CPC).