Direct Patterning of Self-Assembled Monolayers by Stamp Printing Method and Applications in High Performance Organic Field-Effect Transistors and Complementary Inverters

Self-assembled monolayer (SAM) is usually applied to tune the interface between dielectric and active layer of organic field-effect transistors (OFETs) and other organic electronics, a time-saving, direct patterning approach of depositing well-ordered SAMs is highly desired. Here, a new direct patterning method of SAMs by stamp printing or roller printing with special designed stamps is introduced. The chemical structures of the paraffin hydrocarbon molecules and the tail groups of SAMs have allowed to use their attractive van der Waals force for the direct patterning of SAMs. Different SAMs including alkyl and fluoroalkyl silanes or phosphonic acids are used to stamp onto different dielectric surfaces and are characterized by water contact angle, atomic force microscopy, X-ray diffraction, and attenuated total reflectance Fourier transform infrared. The p-type dinaphtho[2,3-b:2,3-f]thieno[3,2-b]thiophene (DNTT) and n-type F16CuPc OFETs show competitive mobility as high as 3 and 0.018 cm(2) V-1 s(-1), respectively. This stamp printing method also allows to deposit different SAMs on certain regions of same substrate, and the complementary inverter consists of both p-type and n-type transistors whose threshold voltages are tuned by stamp printing SAMs and shows a gain higher than 100. The proposed stamp or roller printing method can significantly reduce the deposition time and compatible with the roll-to-roll fabrication.