Fullerene Monolayer-Modified Porous Si. Synthesis and Photoelectrochemistry

Functionalization of Oxide-Free Silicon Surfaces with Redox-Active Assemblies

“…From an electrochemical point of view, the multiredox activity exhibited by fullerenes in solution was however not retained when immobilized on Si–H. As a matter of fact, only a single reduction step appearing more or less reversible was visible for C 60 -modified Si–H surfaces. ,,, Such differences between the electrochemical behavior of surface-confined and dissolved species are not uncommon and have already been reported for fullerene self-assembled monolayers (SAMs) attached to gold. ,− In the case of gold, it has been claimed that the compensating ion transport during the reduction process of bound C 60 would be inhibited owing to the high packing density of the fullerene SAMs. For silicon-confined C 60 , the ion transport is expected to be not affected to a large extent as the C 60 monolayers were globally poorly densely packed.…”

“…The direct attachment of C 60 to Si–H surfaces has been achieved via a hydrosilylation reaction with the CC bonds on C 60 following either solvent casting or vapor deposition of C 60 at ca. 200 °C. , However, this method yielded poorly dense C 60 monolayers ( 39 , Scheme ). The surface coverage of C 60 was only 10% of the estimated one full monolayer coverage (1.9 × 10 –10 mol cm –2 ) .…”

Self-Assembly and Characterization of Fullerene Monolayers on Si(100) Surfaces

“…The Si surface thus treated is known to be H-terminated. , We also checked the H-termination by galvanostatic potential−time transients . The above pretreated Si wafer was reacted with C 60 to form the C 60 monolayer on Si surface following either solvent casting or vapor deposition of C 60 .…”

“…Recently, direct functionalization of Si surface by utilizing H-terminated Si surfaces has been exploited. − This direct functionalization ought to facilitate the charge transfer between the substrate and the attaching functional group as the distance between them is shortened compared to the indirect way of using organosilanes. We and others have found that thermally driven chemical reactions occurred between C 60 monolayer molecules and the H-terminated Si(100) substrate surfaces. − We are able to covalently bond fullerene molecules directly on H-terminated Si(100) surfaces based on homogeneous hydrosilylation. A homogeneous hydrosilylation reaction under heat is shown in eq 1…”

Redox-active Si(100) surfaces covalently functionalised with [60]fullerene conjugates: new hybrid materials for molecular-based devices

“…40 Specifically, it has been observed that a series of [60]fullerene-derived carboxylic acids could be easily adsorbed on (n-and p-type) GaAs and ZnO crystals, revealing a strong influence of the electron-accepting [60]fullerene moieties on the superficial properties (work function and band bending) of the semiconductor as a consequence of the interaction between the frontier orbitals of the carbon spheres with the valence and conduction bands. 40 To the best of our knowledge, if two works on porous silicon substrates 41 and one on Si(111) are excluded, 42 only Feng and Miller have described in 1999 the functionalisation of hydrogenated flat Si(100) with [60]fullerenes. 43 In particular, they reported the self-assembly of C 60 molecules on flat Si(100) surfaces via direct tethering of the carbon sphere to the surface as shown by electrochemical and fast atom bombardment mass spectrometry measurements.…”