1-Dodecanethiol Self-Assembled Monolayers on Cobalt

Abstract

Cobalt and its alloys are used in a broad range of application fields. However, the use of this metal is especially limited by its strongly oxidizable nature. The use of alkanethiol self-assembled monolayers (SAMs) is a very efficient way to protect against such oxidation and/or to inhibit corrosion. This surface modification method has been particularly applied to oxidizable metals such as copper or nickel, yet the modification of cobalt surfaces by alkanethiol SAMs received limited attention up to now. In this work, we study the influence of parameters by which to control the self-assembly process of 1-dodecanethiol monolayers on cobalt: nature of the surface pretreatment, solvent, immersion time, and concentration. Each of these parameters has been optimized to obtain a densely packed and stable monolayer able to efficiently prevent the reoxidation of the modified cobalt substrates. The obtained monolayers were characterized by X-ray photoelectron spectroscopy (XPS), polarization modulation infrared reflection-absorption spectroscopy, and contact angle measurements. The stability of the optimized 1-dodecanethiol monolayer upon air exposure for 28 days has been confirmed by XPS.

1-Dodecanethiol based highly stable self-assembled monolayers for germanium passivation

“…The appearance of S 2p peaks for NDM-Ge maximum at ∼162.6 eV was attributed to sulfur bonded to Ge substrate (Fig. 3f), consistent with previously reported results [21,38]. Moreover, as shown in Fig.…”

“…Furthermore, to estimate the components and states of the assembled NDM molecules, the corresponding S 2p regions were collected to identify the reaction type between thiols and Ge substrate. Generally, the S 2p spectrum of SAMs on different substrates (metal or semiconductor) exhibits three states: centered at 162-163, around 164 and around 168 eV, corresponding to thiolates, unbound thiols and sulfinates, respectively [38]. In the self-assembled process of thiolate on typical gold substrate, the presence of these three states of S 2p components were observed in the reported literatures [35,42].…”

Recovering ferromagnetic metal surfaces to fully exploit chemistry in molecular spintronics

“…21,22 At the end of the chain, phosphonic acids (CnP) have been widely used for the functionalization of metal oxides, 21,22 while thiols (CnS) have been the common choice for the functionalization of coinage metals 23,24 and in some cases ferromagnetic metals like nickel [25][26][27][28][29][30] or cobalt. 28,31,32 SAMs have found wide application in different aspects of organic electronics. 33,34 In organic spintronics, despite they are less exploited than organic semiconductors, 2,35,36 SAMs have already shown their potential as tunnel barriers.…”

Thiolate-Bonded Self-Assembled Monolayers on Ni(111): Bonding Strength, Structure, and Stability

“…However, renewed interest in SAMs deposited onto substrates and electrodes of 3d ferromagnetic metals (specifically Ni, Co, and Fe) has arisen in recent years 15,16,19 and is expected to grow steadily due to the crucial role envisaged for organic layers in molecular spintronics. 20−23 The latter discipline relies on the ability to manipulate the electron spin in organic molecular materials, which can provide a chemical route for tailoring the magnetic response in electronic devices.…”