Thieno[3,2-b]thiophene oligomers and their applications as p-type organic semiconductors?

Journal of Materials Chemistry Pub Date: 2009-04-03 DOI: 10.1039/B900979E

Abstract

This study describes the synthesis, characterization and electronic properties of a novel series of soluble thieno[3,2-b]thiophene oligomers (1a and b and 2a and b) for thin film transistor (TFT) applications. All the compounds were synthesized in high yield using Pd-catalyzed Stille or Suzuki coupling reactions and were substituted by two dodecyl groups at the 3- or 4-position of the thiophene unit to ensure the solubility for facile device fabrication. Aryl units such as phenyl and naphthyl were used for ‘end-capping’ to provide stability against oxidation. The design of these materials has focused on their self-assembly and solution processability. All the compounds have been characterized by 1H, 13C NMR, and elemental analysis. Their electronic and optical properties were investigated using UV-Vis and photoluminescence spectroscopy, cyclic voltammetry, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). High-resolution STM images of 1a and 2a adsorbed on HOPG revealed highly ordered self-organized domains. Two-dimensional wide-angle X-ray scattering (2D-WAXS) was used to study the solid state packing of 1a and 2a. Top-contact OTFT devices from 1a were prepared by spin coating and showed promising behaviour with mobilities up to 3.11 × 10?2 cm2V?1 s?1 and on/off ratios up to 104.

Graphical abstract: Thieno[3,2-b]thiophene oligomers and their applications as p-type organic semiconductors
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