We demonstrate the use of a cross-linking chemistry for an amorphous fluoropolymer gate dielectric, poly(perfluorobutenylvinylether) commercially known as Cytop. Spin-coated films of Cytop exhibit good gate insulating properties as well as provide excellent OFET operational stability. However, these devices operate at large voltages because the dielectric layer thickness is typically ∼450−600 nm. When the thickness of a Cytop dielectric layer is decreased below 200 nm, the device yields are dramatically reduced due to pinhole formation. Our new cross-linked Cytop (C-Cytop) formulation deposited by spin-coating enables uniform thin films on top of various organic semiconductors that exhibits low gate leakage current densities ( 2 MV cm−1). Our approach results in C-Cytop dielectric films as thin as 50 nm, thus allowing the fabrication of reliable p- and n-channel top-gate OFETs operating at very low-voltages (<5 V). The most remarkable properties of thi...