Synthesis and thin films characterization of new anthracene-core molecules for opto-electronic applications

Two new anthracene-core conjugated molecules, 1-(9-anthrylvinyl)-4-benzyloxybenzene (AVB) and 1,4-bis(9-anthrylvinyl)benzene (AV2B), were synthesized by the Wittig reaction. Organic thin films based on these derivatives were elaborated using thermal evaporation under high vacuum. The UV-vis film spectra show an anthracene-type absorption behavior for the two π-conjugated systems with an optical gap of 2.77 eV for AVB and 2.55 eV for AV2B. These derivatives reveal practically the same photoluminescence spectra and exhibit blue emitting films. However, the electrical properties investigations demonstrate an enhancement in the electrical conductivity for AVB resulting from the high crystallinity of the film and attributed to a well intermolecular charge transfer. Finally, the conduction mechanisms in the solid state are discussed in terms of space charge limited current (SCLC) and correlated to the film morphology.