Blue-Emitting Soluble Poly(m-phenylenevinylene) Derivatives

Soluble poly( m -phenylenevinylene) derivatives ( 4 ) were synthesized via Wittig−Horner reaction. The number-average degree of polymerization was estimated to be around 25−35. On the basis of FT-IR and 1 H NMR spectra, the olefins in the polymers were confirmed to be predominantly in the trans -configuration. A model compound, 3,5-distyryl-4-hexyloxytoluene ( 5 ), was also synthesized to aid the structural characterization. Comparison of photoabsorption and emission characteristics between 4 and 5 indicated that the m- phenylene effectively interrupted the conjugation, allowing predictable color control in the π-conjugated polymers. At low temperature, the fluorescence of 4 was readily resolved into two peaks, suggesting the predominant emissions were from 0−1 and 0−2 transitions. Polymers 4 were found to be highly luminescent in both solution and film states. LED devices using 4 gave blue EL output (emission λ max at 445 and 462 nm).