SYNTHESIS, MORPHOLOGY, AND FIELD-EFFECT MOBILITY OF ANTHRADITHIOPHENES

The synthesis. thin-film morphology, and hole mobility in thin-film tr ansistors (TFTs) of compounds based on the novel anthradithiophene (AD T) ring system are reported. The parent compound and its 2,8-dihexyl, didodecyl, and dioctadecyl derivatives (DHADT, DDADT, and DOADT, respe ctively), synthesized via alkylated thiophene dicarboxaldehyde acetals , were investigated. They all form highly ordered polycrystalline vacu um-evaporated films with mobilities as high as 0.15 cm(2)/(V s), as hi gh as has ever been observed for a polycrystalline organic material. D OADT has a mobility of 0.06 cm(2)/(V s) even though 70% of its molecul ar volume is occupied by hydrocarbon chains. DHADT was cast from solut ion under atmospheric conditions onto a TFT giving a mobility of 0.01- 0.02 cm(2)/(V s), Thus, the alkylated ADTs combine a pentacene-like in trinsic mobility with greater solubility and oxidative stability.