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Keywords:

  • Field-effect transistors, organic;
  • Oligothiophenes;
  • Thin-film transistors, organic

Abstract

A series of new organic semiconductors for organic thin-film transistors using dithieno[3,2-b:2′,3′-d]thiophene as the core have been synthesized. In work reported by Liu, Zhu, and co-workers on p. 426, the phenyl-substituted compound exhibited a high mobility of 0.42 cm2 V–1 s–1 and an on/off ratio of 5 × 106. Weekly shelf-life tests of the transistors based on the bis(diphenyl)-substituted thiophene under ambient conditions showed that the mobility was almost unchanged after more than two months, demonstrating potential for applications in future organic electronics.

A series of new organic semiconductors for organic thin-film transistors (OTFTs) using dithieno[3,2-b:2′,3′-d]thiophene as the core are synthesized. Their electronic and optical properties are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis and photoluminescence spectroscopies, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The compounds exhibit an excellent field-effect performance with a high mobility of 0.42 cm2 V–1 s–1 and an on/off ratio of 5 × 106. XRD patterns reveal these films, grown by vacuum deposition, to be highly crystalline, and SEM reveals well-interconnected, microcrystalline domains in these films at room temperature. TGA and DSC demonstrate that the phenyl-substituted compounds possess excellent thermal stability. Furthermore, weekly shelf-life tests (under ambient conditions) of the OTFTs based on the phenyl-substituted compounds show that the mobility for the bis(diphenyl)-substituted thiophene was almost unchanged for more than two months, indicating a high environmental stability.