Delivering Octadecylphosphonic Acid Self-Assembled Monolayers on a Si Wafer and Other Oxide Surfaces

Abstract

We describe a simple experimental approach for delivering self-assembled monolayers (SAMs) of octadecylphosphonic acid (OPA) on many oxide surfaces using a nonpolar medium with a dielectric constant around 4 (e.g., trichloroethylene). This approach readily results in the formation of full-coverage OPA SAMs on a wide variety of oxide surfaces including cleaved mica, Si wafer, quartz, and aluminum. Especially, the availability of delivering full-coverage OPA SAM on a Si wafer is unique, as no OPA SAMs at all could be formed on a Si wafer when using a polar OPA solution. The reason a nonpolar solvent is superior lies in the very fact that the hydrophilic OPA headgroup tends to escape from the nonpolar solution and is thus enriched at the medium-air interface. It is these OPA headgroups seeking a hydrophilic surface that make possible the well-controlled OPA monolayer on an oxide surface.

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

“…This is also the case for other solution methods, such as the Langmuir-Blodgett (LB) [ 26 ] or spin-coating method. [27][28][29] Although the deposition time or complexity of the fabrication process may not be the fi rst priority for devices in the laboratory, they are critical in the mass production of organic electronics where many devices with a variety of functions are required to be fabricated together onto the substrate and thus direct patterning of SAMs is highly desired especially for the development of organic complementary metal-oxide semiconductors (CMOS). As a result, there is a strong demand to develop a direct patterning method of SAMs which can functionalize different locations of a substrate for the large area toward the mass production of organic electronic components and ultimately CMOS circuits.…”

Phosphine Oxide Monolayers on SiO2 Surfaces

“…[5,6] To date, the studies of monolayer formation of phosphonates have mainly focused on phosphonic acids. [7][8][9][10] However, for certain applications, the less polar phosphine oxides are more desirable. Phosphine oxides are readily soluble in nonpolar organic solvents, such as toluene and mesitylene, and are compatible with many types of semiconducting materials.…”

Organic field-effect transistor with octadecyltrichlorosilane (OTS) self-assembled monolayers on gate oxide: effect of OTS quality

“…Besides, the dielectric constant of the solvent affects the coverage of the SAM molecules. Nie et al have reported different behaviours depending whether SAMs have a polar head group and/or a non polar alkyl chain (as OTS) or not [31]. In the case of a solvent permittivity ε s > 5, the SAM molecules start to interact significantly with the solvent, thus disrupting the self-assembly on the substrate.…”