Covalently bridged interface engineering for suppressing interfacial defects toward high-stability and low-voltage...

Achieving simultaneously high operational stability and low-voltage operation is critical for the practical deployment of organic field-effect transistors (OFETs) in flexible and integrated electronics. However, the heterogeneous organic semiconductors (OSCs)/dielectric interface, where carriers are transported, inevitably introduces defects originating from structural and energetic disorder that lead to instability. Here, we demonstrate that the insulating alkyl chains could serve as a dielectric component to fabricate alkylated OFETs. This interface-free OSC/dielectric configuration reduces interfacial defects and enables efficient charge transport with intrinsic structural passivation. Under this configuration, the 2,9-didecyldinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (C₁₀-DNTT) FET exhibits operational stability over 10,000 s and an ultrahigh intrinsic gain of 7.52 × 10⁴. The corresponding inverters show exceptional static (gains of 127.6 and noise margin of 95.3% at V_DD = 2.5 V) and dynamic characteristics (signal-delay time constants of 50 μs at V_DD = 1 V), with negligible shift over 50 switch cycles, demonstrating excellent electrical performance and reliability of low-voltage organic circuits. This molecular-level OSC/dielectric integration strategy provides a general pathway for addressing key limitations for the practical deployment of OFETs in flexible and integrated electronics.