High performance organic thin film transistors using chemically modified bottom contacts and dielectric surfaces

• 4-fluorothiophenol is used as the first SAM to modify the Ag bottom contacts.
• A second SAM of either HMDS or OTS-C8 is applied to modify the gate oxide interface.
• PTDPPTFT4 based BC OTFT employing this orthogonal self-assembly approach to 0.9 cm2V−1s−1.

A compatible process of orthogonal self-assembled monolayers (SAMs) is applied to intentionally modify the bottom contacts and gate dielectric surfaces of organic thin film transistors (OTFTs). This efficient interface modification is first achieved by 4-fluorothiophenol (4-FTP) SAM to chemically treat the silver source–drain (S/D) contacts while the silicon oxide (SiO2) dielectric interface is further primed by either hexamethyldisilazane (HMDS) or octyltrichlorosilane (OTS-C8). Results show that the field effect mobilities of the bottom-gate bottom-contact PTDPPTFT4 transistors were significantly improved to 0.91 cm2 V−1 s−1.

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