D-π-D chromophores based on dithieno[3,2-b:2′,3′-d]thiophene (DTT): Potential application in the fabrication of solar cell

In this work, four stable dithieno[3,2-b:2',3'-d]thiophene-based pi-extended molecules were designed and synthesized via a Pd-catalysed Sonogashira coupling reaction. The structures of these symmetrical compounds, including dithieno[3,2-6:2',3'-d]thiophene (DTT) as the pi-center and various donor (D) groups, were determined on the basis of NMR spectral data, elemental analysis, and X-ray crystallography. The photo-physical properties of the DTT-based derivatives 2 were fully investigated in both solution and the solid state. The notable optical features of their solid-state powders showed significant red-shifts in comparison with the luminescence of their dilute dichloromethane solutions. These results combined with the theoretical calculations indicate that they are promising candidates for several applications in electronic and optoelectronic devices, as well as organic dyes for solar cells. (C) 2016 Elsevier Ltd. All rights reserved.