Cold Crystallization of the Organic n-Type Small Molecule Semiconductor 2-Decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene S,S,S′,S′-Tetraoxide

The asymmetric n-type Ph-BTBT-C-10 derivative 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene S,S,S',S'-tetraoxide is structurally investigated in the thin film regime. After film preparation by spin coating and physical vapor deposition, a rather disordered structure is observed, with a strong change of its internal degree of order upon heating. At 95 degrees C, a transition into a layered structure of upright standing molecules without any in-plane order appears, and at 135 degrees C, crystallization takes place. This phase information is combined with surface morphological studies and charge carrier mobility measurements to describe the structure and thin film transistor applicability of this molecule.