Charge transfer complexes of a benzothienobenzothiophene derivative and their implementation as active layer in solution-processed thin film organic field-effect transistors

Herein, we report on the synthesis and structural characterization of novel charge transfer (CT) complexes of the benzothienobenzothiophene derivative C8 O-BTBT-OC8 with the series of FxTCNQ derivatives (x = 2, 4). The degree of charge transfer and HOMO–LUMO gap energies were evaluated by spectroscopic means and by DFT calculations. Thin films of the (C8 O-BTBT-OC8 )(F4 TCNQ) complex were prepared by a simple solution shearing technique and by blending the active materials with poly-styrene. X-Ray diffraction and IR/Raman spectroscopy techniques were instrumental for the structural identification of the films, which belonged to the same phase as the resolved single crystal. The films were implemented as an active layer in organic field-effect transistor (OFET) devices, which exhibited an n-type behavior in ambient conditions in agreement with the theoretical calculations.