Solution-processed thin films of a charge transfer complex for ambipolar field-effect transistors

Charge transfer (CT) complexes are attracting great interest as potential candidate ambipolar semiconductors. However, their application in organic field-effect transistors (OFETs) has been limited to ideal single crystals or to films prepared by co-evaporation of their components, hindering their potential for real applications. Here, we report the preparation of thin films of the CT complex DBTTF-TCNQ using a simple solution shearing technique. This was achieved by blending the active materials with polystyrene to promote film processability, reproducibility and stability. Infrared and Raman spectroscopies were used, respectively, for charge transfer degree estimation and structural identification of the films. The resulting OFET devices, fabricated and measured completely under environmental conditions, exhibited an ambipolar field-effect. Thus, this work opens new perspectives for the application of CT salts in electronic devices.