Alkylation of Porous Silicon by Direct Reaction with Alkenes and Alkynes

Bateman, J.E.; Eagling, Robert; Worrall, David R.; Horrocks, Benjamin R.; Houlton, Andrew

doi:10.1002/(sici)1521-3773(19981016)37:19<2683::aid-anie2683>3.0.co;2-y

Cited by 179 publications

(164 citation statements)

References 10 publications

Supporting

Mentioning

154

Contrasting

Order By: Relevance

“…Therefore, based on FTIR spectral data and quantum mechanical calculations, the formation of surface heterocycles (either 1,1-or 1,2-bridged products) involving bridged silicon surface atoms cannot be disregarded on Si(100)-H. 125 Interestingly, analogous discrepancies for the immobilization of 1-alkynes are found in the porous silicon literature. 28,84,183 Whether the different conclusions of Sun et al 126,166 and Cerofolini and co-workers 180 with regards to the hydrosilylation mechanism are due to either the different unsaturated hydrocarbons used (e.g. different lengths), or due to differences in reaction conditions, surface preparation protocols or characterization techniques, is not clear at present and will require further work.…”

Section: Photochemical Hydrosilylation Reactions and Mechanistic Consmentioning

confidence: 97%

“…1). [75][76][77][78] Hydrogenated silicon surfaces are attractive to work with because of their ease of preparation, 78 their relative stability in air 79,80 and during brief water ring procedures, 31,76 and their lack of appreciable reactivity toward a range of common solvents (including acetonitrile, 81 diethyl ether, 46 chlorobenzene, 82 hexane, 83 toluene 84 and mesitylene 85,86 preparation of covalent organic layers by wet chemical methods. 87 Notable exceptions to the typically straightforward conditions are [2+2] and [4+2] cycloaddition reactions under 'dry' UHV conditions.…”

Section: Surface Preparationmentioning

confidence: 99%

See 1 more Smart Citation

Wet chemical routes to the assembly of organic monolayers on silicon surfaces via the formation of Si–C bonds: surface preparation, passivation and functionalization

2010

View full text Add to dashboard Cite

Section: Photochemical Hydrosilylation Reactions and Mechanistic Consmentioning

confidence: 97%

Section: Surface Preparationmentioning

confidence: 99%

Wet chemical routes to the assembly of organic monolayers on silicon surfaces via the formation of Si–C bonds: surface preparation, passivation and functionalization

2010

View full text Add to dashboard Cite

“…Thermal hydrosilylation reactions using dry, degassed 1-alkenes have been reported to produce surfaces with up to 70 % alkyl passivation, depending on the steric hindrance of the ligand at the surface. [83][84][85][86] Si-H bond cleavage, and subsequent hydrosilylation of the Si surface, has also been reported to have been accomplished by UV irradiation (λ ≤ 350 nm) at room temperature, producing surfaces with as high as 45% surface coverage. 87 1.…”

Section: Si H + Simentioning

confidence: 74%

“…Thermal-and UVassisted hydrosilylation reactions are perhaps the most commonly cited silicon surface alkylation reactions. [81][82][83][84][85][86][87][88] These reactions have long been accepted by most (not all 83 ) groups to proceed via the addition of surface silicon radicals to unsaturated carboncarbon bonds. Furthermore, these reactions are commonly accepted to be initiated by the homolytic cleavage of the Si-H bond, which is accomplished either thermally or photolytically and results in reactive silicon radicals.…”

Section: Si H + Simentioning

confidence: 97%

See 1 more Smart Citation

Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence

Radlinger¹

View full text Add to dashboard Cite

While silicon has long been utilized for its electronic properties, its use as an optical material has largely been limited due to the poor efficiency of interband transitions. However, discovery of visible photoluminescence (PL) from nanocrystalline silicon in 1990 triggered many ensuing research efforts to optimize PL from nanocrystalline silicon for optical applications. Currently, use of photoluminescent silicon nanoparticles (Si NPs) is commercially limited by: 1) the instability of the energy and intensity of the PL, and 2) the low quantum yield of interband PL from Si NPs.Herein, red-emitting, hydrogen-passivated silicon nanoparticles (H-Si NPs) were synthesized by thermally-induced disproportionation of a HSiCl 3 -derived (HSiO 1.5 )n polymer. The H-Si NPs produced by this method were then subjected to various chemical and physical environments to assess the long-term stability of the optical properties as a function of changing surface composition. This dissertation is intended to elucidate correlations between the reported PL instability and the observed changes in the Si NP surface chemistry over time and as a function of environment.First, the stability of the H-Si NP surface at slightly elevated temperatures towards reactivity with a simple alkane was probed. The H-Si NPs were observed by FT-IR spectroscopy to undergo partial hydrosilylation upon heating in refluxing hexane, in addition to varying degrees of surface oxidation. The unexpected reactivity of the Si surface in n-hexane supports the unstable nature of the H-Si NP surface, and furthermore implicates the presence of highly-reactive Si radicals on the surfaces of the Si NPs. We propose that reaction of alkene impurities with the Si surface radicals is largely responsible for the observed surface alkylation. However, we also present an alternate ii mechanism by which Si surface radicals could react with alkanes to result in alkylation of the surface.Next, the energy and intensity stability of the interband PL from H-Si NPs in the presence of a radical trap was probed. Upon addition of (2,2,6,6,-tetramethyl-piperidin-1-yl)oxyl (TEMPO), the energy and intensity of the interband transition was observed to change over time, dependent on the reaction conditions. First, when the reaction occurred at 4ºC with minimal light exposure, the interband transition exhibited a gradual hypsochromic shift to between 595 nm and 655 nm, versus the λ max of the original low energy emission peak at 700 nm, depending on the amount of TEMPO in the sample.Second, when the reaction proceeded at room temperature with frequent exposure to 360 nm irradiation, the original interband transition at 660 nm was quenched while a new peak at 575 nm developed. Based on all the data collected and analyzed, we assign the 595 -655 nm transition as due to interband exciton recombination from Si NPs with reduced diameters relative to the original Si NPs. We furthermore assign the 575 nm transition as due to an oxide-related defect state resulting from rapid oxidation of pho...

show abstract

DNA On Silicon Devices: On-Chip Synthesis, Hybridization, and Charge Transfer

et al. 2002

Self Cite

View full text Add to dashboard Cite

Surface-immobilized DNA has an increasing number of roles in science and technology because of the ease with which it can be manipulated chemically and enzymatically in a highly controlled manner. Complex DNA architectures [1] and the use of DNA as a scaffold for making electronic connections [2] have been reported, and the use of DNA as a component in so-called molecular electronics has been frequently advocated. [3] Applications also include DNA microarrays [4] for sequencing through hybridization, the study of gene expression, and even for prototype computing devices which utilize the fidelity of the hybridization reaction. [5±7] In most cases, the DNA is immobilized on glass, oxidized silicon wafers, or other insulating supports. Methods for combining DNA with electronic materials are anticipated to be increasingly important in light of the considerable interest in DNAbased nanotechnology, [1] DNA-mediated charge transfer, [8] and DNA-based wires. [2] For substrates such as gold [9] or Si, [10] where there is the possibility of charge transfer through the DNA to the surface, immobilization has relied upon the attachment of presynthesized strands. However, to date there has been no demonstration of the use of automated solidphase DNA synthesis nor charge transfer through DNAbased assemblies at a semiconductor. For many proposed applications the ability to combine microelectronic processing techniques, [11] for example, photolithography and micromachining, with automated chemical synthesis has clear advantages. Herein we outline a method that enables the straightforward integration of DNA technology with microelectronics.Hydrogen-terminated surfaces represent the initial state from which silicon semiconductor devices are fabricated. [11] Chidsey and co-workers first demonstrated that such singlecrystal surfaces [12] react with alkenes to give chemically robust Si À C-bonded monolayers, and further advances have shown the applicability of this chemistry to porous silicon. [13±15] The reaction may be driven by thermal, catalytic, electrochemical, and photochemical methods, [13,16] and patterning of the monolayers, for example, by using photolithographic techniques, is possible. We have used a simple protecting group method to produce monolayers with terminal OH groups ( Figure 1); hydrogen-terminated silicon surfaces of oriented (111) single-crystal and porous silicon were alkylated with 4,4'-dimethoxytrityl-protected w-undecenol (trityl triphenylmethyl) by refluxing it in toluene; this is a previously

show abstract

Alkylation of Porous Silicon by Direct Reaction with Alkenes and Alkynes

Abstract: The hydrogen-terminated surface of porous silicon (PS) is sufficiently reactive for the uncatalyzed hydrosilation of alkenes and alkynes. These modifications produce dramatic changes to both the physical and chemical properties of the PS.

Cited by 179 publications

References 10 publications

Wet chemical routes to the assembly of organic monolayers on silicon surfaces via the formation of Si–C bonds: surface preparation, passivation and functionalization

Wet chemical routes to the assembly of organic monolayers on silicon surfaces via the formation of Si–C bonds: surface preparation, passivation and functionalization

Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence

DNA On Silicon Devices: On-Chip Synthesis, Hybridization, and Charge Transfer

Contact Info

Product

Resources

About