Organic planar diode with Cu electrode via modification of the metal surface by SAM of fluorobiphenyl based thiol

Highlights: • Cu electrode is oxidized and grafted with different self-assembled monolayers (SAMs). • Fluorobiphenylthiol (FBPS) and biphenylthiol (BPS) is used for comparison purpose. • In these conditions, DNTT active material based diodes are tested. • FBPS based diode exhibits high mobility due to the organized assembly of FBPS on Cu. • Organized dipolar FBPS molecules improve the mobility by reducing injection barrier. The surface of a copper (Cu) electrode is modified by the combination of preliminary oxidative treatment and grafting of a bifunctional self-assembled monolayer based on fluorobiphenylthiol (FBPS) or biphenylthiol (BPS). In these conditions, a dinaphtho [2, 3-b: 2′,3′-f] thieno [3,2–b] thiophene (DNTT)-based diode exhibits high mobility (0.35 cm².V⁻¹.s⁻¹) due to the formation of organized assembly of FBPS on the oxide Cu that has been partially reduced in Cu₂O; this organization controls that of the semiconductor film. On the other hand, the same treatment of Cu electrode with BPS molecules does not function, due to the disorganization of both the BPS SAM and the DNTT film. These results suggest that a monolayer of dipolar-oriented molecules lowers the injection barrier; steers the semiconductor organization and thereby enhances the performance of the derived electronic component.