Acene containing polyfluorenes for red, green, and blue emission in organic light-emitting diodes

We have introduced acene such as anthracene, naphthacene and pentacene into the main chain of polyfluorene to improve stability and to realize color tuning to pure blue, green and red. High molecular weight acene-containing polyfluorenes are successfully synthesized by the Ni[0] mediated Yamamoto-coupling reaction. Average molecular weights of the copolymers are Mw equals 42000 - 96000 (determined by GPC). By the introduction of 10% of acene moiety, the device stability could be significantly improved, indicating the torsion between the acene and fluorene units suppresses interchain aggregation; the copolymers exhibits stable blue, green and red emission in the anthracene-, naphthacene- and pentacene-containing polyfluorenes, respectively. Onset voltage for light emission is 5 - 30 V and the maximum luminance is 240 - 5200 cd/m 2 . As a side effect an unique color change on UV irradiation could be observed as well as the reason for its appearance determined.