Blue Solid-State Photoluminescence and Electroluminescence from Novel Poly(<i>para</i>-phenyleneethynylene) Copolymers

Abstract

We report the synthesis of a series of random copolymers composed of phenyleneethynylene and 3,7-di-tert-butylnaphthalene units by alkyne metathesis with simple catalyst systems, formed from Mo(CO)6 and 4-chlorophenol in situ. These novel copolymers give rise to efficient (Φ = 0.16−0.76) blue solid-state emission (λmax = 422−443 nm) which can be fine-tuned according to their naphthalene content differing greatly from that of standard dialkyl-PPE (λmax 500−520 nm). The effective and blue-shifted solid-state emission is a result of disrupting the solid-state alignment thereby diminishing π-π interactions of the copolymers in addition to the efficient interruption of planarization of the conjugated backbone. Electroluminescent multilayer devices showed low turn-on voltages (5.5 V) and a maximum brightness of 100 cd/m2.