Effects of solution-shearing process parameters on charge carrier mobility in green solvent-processed organic field-effect transistors

In this work, we explored the effect of solution-shearing processing parameters, coating speed and substrate temperature, on the electrical properties of solution-processed organic field-effect transistors (OFETs) based on 2-decyl-7-phenyl[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-C10) when green solvents are used. Organic semiconductor thin films were solution-sheared with various coating speeds and substrate temperatures and film morphologies/microstructures were investigated by atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis. Our data demonstrate that crystal growth of Ph-BTBT-C10 molecule is highly affected by the two solution shearing processing parameters and, especially, the OFET devices fabricated with cyclohexanone as green solvent exhibited the charge carrier mobility as high as 5.1 cm2/Vs with optimized processing condition. This work could further provide a guideline for process optimization for fabricating high-performance green solvent-processed OFETs.