Abstract:The mechanism of the formation of Si-C bonded monolayers on silicon by reaction of 1-alkenes with hydrogen-terminated porous silicon surfaces has been studied by both experimental and computational means. We propose that monolayer formation occurs via the same radical chain process as at single-crystal surfaces: a silyl radical attacks the 1-alkene to form both the Si-C bond and a radical center on the beta-carbon atom. This carbon radical may then abstract a hydrogen atom from a neighboring Si-H bond to propa… Show more
“…A number of reports have examined, quantified, and confirmed the kinetics related to this reaction using first-principle calculations. 149,150 Another method is hydrosilylation initiated by hydride abstraction using compounds such as triphenylcarbenium cations ( Figure 6). 151 In this case, a positively charged silicon surface is created after the cation removes H − , which in turn enables a nucleophilic attack by the CC double bond (electron-rich).…”
Section: Hydrosilylation Of H-terminated Surfacesmentioning
Figure 2. Cross-sectional SEM images of NW arrays (a) 2 μm and (b) 5 μm in length. Scale bars are 10 μm. (c) Transmission spectra of arrays of 2 μm (green) and 5 μm (black) long nanowires fabricated on 7.5 μm thick silicon. A large intensity reduction is observed through a red-shift in the transmitted light after nanowire fabrication, which indicates enhanced light trapping. Reprinted with permission from ref 53.
“…A number of reports have examined, quantified, and confirmed the kinetics related to this reaction using first-principle calculations. 149,150 Another method is hydrosilylation initiated by hydride abstraction using compounds such as triphenylcarbenium cations ( Figure 6). 151 In this case, a positively charged silicon surface is created after the cation removes H − , which in turn enables a nucleophilic attack by the CC double bond (electron-rich).…”
Section: Hydrosilylation Of H-terminated Surfacesmentioning
Figure 2. Cross-sectional SEM images of NW arrays (a) 2 μm and (b) 5 μm in length. Scale bars are 10 μm. (c) Transmission spectra of arrays of 2 μm (green) and 5 μm (black) long nanowires fabricated on 7.5 μm thick silicon. A large intensity reduction is observed through a red-shift in the transmitted light after nanowire fabrication, which indicates enhanced light trapping. Reprinted with permission from ref 53.
“…Different methods of initiation of this chain reaction and a variety of measurements with possible applications to molecular conductance have recently focused on this molecule and similar systems on a series of substrates [188,208,222,411, [427][428][429][430][431][432][433][434][435][436][437][438]. It is worth noting that in the case of radical initiation with TEMPO [256,420], this species can serve both as the initiator of the reaction and as a protecting group, as illustrated in Fig.…”
Section: Chemistry Of Partially Hydrogen-covered Silicon Surfacesmentioning
“…Three different Si-H stretching vibrations as well as the vibration corresponding to SiH 2 scissoring appear in the spectrum in figure 1, with SiH 3 stretching at 2140cm -1 , SiH 2 at 2120cm -1 and SiH at 2091cm -1 [11]. The spectrum also shows a small amount of oxidation, by the peaks at 1075cm -1 that corresponds to Si-O stretching vibrations [12].…”
Section: Characterisation Of the Porous Silicon Surfacementioning
The control of protein binding into nanostructured porous surfaces is highly relevant to the development of advanced biosensors and other biodevices. Here, an investigation of the covalent immobilisation of a model protein (albumin) onto porous silicon (pSi) films was conducted using a new alkene linker, the synthesis of which was developed. This alkene linker contained both hydrophobic and hydrophilic (oligoethylene glycol) sections and terminated in a protected thiol. The alkene was attached to freshly etched porous silicon via thermal hydrosilylation, where further surface reactions resulted in the attachment of a maleimido N-hydroxysuccinimidyl (NHS) heterobifunctional crosslinker. Albumin was then covalently immobilised on the porous silicon layer through reaction of the protein's amine groups and the NHS functional group of the crosslinker. Surface modification reactions were monitored by infrared spectroscopy and interferometric reflectance spectroscopy. Protein binding was monitored by infrared spectroscopy, fluorescence imaging and atomic force microscopy.
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