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

Abstract

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 cm2 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.

Reconfigurable Complementary Logic Circuits with Ambipolar Organic Transistors

“…Dipoles due to the ODPA treatment are also included by means of surface charges at the insulator-semiconductor interface (N is = 2 × 10 11 cm −2 ). ODPA is an alkane phosphonic acid-based SAM with positive charges facing the semiconductor 11 42 . This explains the different hole and electron on-voltages (V on,h ≈ −20 V, V on,e ≈ 0 V) obtained from the transfer characteristics shown in Fig.…”

“…The fabrication of p- and n-type organic thin-film transistors (OTFTs) requires the development and deposition of two different semiconductors 10 11 12 . In addition, each of them has to be carefully optimized by suitable temperature annealing 13 and appropriate engineering of both the insulator-semiconductor 14 15 16 and the metal-semiconductor interfaces 17 18 19 20 21 .…”

Understanding the Meniscus‐Guided Coating Parameters in Organic Field‐Effect‐Transistor Fabrications

“…After crystal thin films deposition, top source and drain electrodes were fabricated by gold (Au) transfer method. After Si/SiO 2 substrate was hydrophobic treated by immersion as reported previously, Au was thermally deposited with TEM copper grid as mask (≈200 µm × 40 µm in size) to form the Au electrodes . The evaporation rate, thickness and vacuum base pressure were 0.2 Å s −1 , 200 nm, and 5 × 10 −6 Torr, respectively.…”

Marangoni‐Effect‐Assisted Bar‐Coating Method for High‐Quality Organic Crystals with Compressive and Tensile Strains

“…Then the C 8 ‐BTBT crystals were grown by using above bar‐coating method. For OTS treatment, the same method presented before was used . The thermal evaporated C 8 ‐BTBT layer was deposited at 0.1 Å s −1 in a vacuum chamber.…”