Characterization of [1]Benzothieno[3,2-b]benzothiophene (BTBT) Derivatives with End-Capping Groups as Solution-Processable Organic Semiconductors for Organic Field-Effect Transistors

Solution-processable [1]benzothieno[3,2-b]benzothiophene (BTBT) derivatives with various end-capping groups, 2-(phenylethynyl)benzo[b]benzo[4,5]thieno[2,3-d]thiophene (Compound 1), 2-octyl-7-(5-(phenylethynyl)thiophen-2-yl)benzo[b]benzo[4,5]thieno[2,3-d]thiophene 2), and triisopropyl((5-(7-octylbenzo[b]benzo[4,5]thieno[2,3-d]thiophen-2-yl)thiophen-2-yl)ethynyl)silane 3), have been synthesized characterized as active layers for organic field-effect transistors (OFETs). Thermal, optical, electrochemical properties of the newly compounds were using thermogravimetric analysis (TGA), a differential scanning calorimeter (DSC), UV–vis spectroscopy, cyclic voltammetry (CV). Thin films each compound formed solution-shearing method thin film surface morphology texture corresponding atomic force microscopy (AFM) θ–2θ X-ray diffraction (XRD). All semiconductors exhibited p-channel characteristics in ambient Compound 1 showed highest electrical performance carrier mobility ~0.03 cm2/Vs current on/off ratio ~106.