Synthesis, structure, and optoelectronic properties of a new twistacene 1,2,3,4,6,13-hexaphenyl-7 : 8,11 : 12-bisbenzo-pentacene

We report the synthesis, optical and electrochemical properties, as well as the fabrication of light-emitting devices for a new twistacene 1,2,3,4,6,13-hexaphenyl-7 : 8,11 : 12-bisbenzo-pentacene (HBP 1). Its structure, determined by X-ray crystallography, confirmed that this material has a twisted topology with the torsion angle as high as 23.0°. HBP 1 showed bright green emission both in solution and solid state. The HOMO-LUMO gap of HBP 1 calculated from the difference between the half-wave redox potentials (E_1/2^ox = +0.74 eV and E_1/2^red = -1.93 eV) is 2.67 eV, which is in good agreement with the band gap, 2.64 eV, derived from the UV-Vis absorption data. Organic light emitting devices using HBP 1 as the emitters have been fabricated. The results revealed that twistacenes are promising materials to enhance the efficiency of OLEDs. © 2010 The Royal Society of Chemistry.