Modification of alkyl side chain on thiophene-containing benzothieno [3,2-b]benzothiophene-based organic semiconductors for organic field-effect transistors

In this study, three new organic semiconductors based on benzothieno [3,2-b]benzothiophene with double thiophene rings and different types of alkyl side chains were synthesized and characterized as active layers for organic field-effect transistors. Physicochemical properties of the newly synthesized organic compounds including thermal, optical, and electrochemical properties were characterized through thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), UV-vis spectroscopy, and cyclic voltammetry (CV). The thin film surface morphology and texture of all three compounds fabricated by solution-shearing process were analyzed via atomic force microscopy (AFM) and theta-20 X-ray diffraction (XRD). All semiconductor thin films showed p-channel activity and the compound with monoalkylated 2-ethylhexyl group as a substituent exhibited the highest electrical performance with carrier mobility of 0.033 cm(2)/Vs and current on/off ratio of similar to 10(6).

Automated summary

Three new organic semiconductors based on benzothieno[3,2-b]benzothiophene were synthesized and characterized. The compound with monoalkylated 2-ethylhexyl group exhibited the highest electrical performance.