SungYong Seo

In this paper, four organic materials based on dithieno[3,2‐b : 2’,3’‐d]thiophene (DTT) core structure with end‐capping groups (phenyl and thienyl) and linker (acetylenic and olefinic) between DTT‐core and end‐capping groups were synthesized and characterized as solution‐processable organic semiconductors (OSCs) for organic field‐effect transistors (OFETs). Thermal, optical, and electrochemical properties of the corresponding materials were determined. Next, all DTT‐derivatives were coated by solution‐shearing method, and the thin‐film microstructures and morphologies were investigated. To investigate the electrical performance of four newly synthesized DTT‐derivatives, bottom‐gate/top‐contact OFETs were fabricated and characterized in ambient condition. It was found that substitution of acetylenic for olefinic linkers between DTT‐cores and end‐capping groups enhanced device performance. Especially, the resulting OFETs based on the compound containing phenylacetylene exhibited the highest hole mobility of 0.15 cm 2 /Vs and current on/off ratio of ∼10 6 , consistent with film morphology and texture showing long range interconnected crystalline grains and strong diffraction peaks.