Attachment Chemistry of PCBM to a Primary-Amine-Terminated Organic Monolayer on a Si(111) Surface

Abstract

Interfacing multifunctional molecules with semiconductor surfaces has a variety of applications; however, it is important to understand the selectivity of target surface reactions to produce the surface with desired functionality. In this work, a silicon surface modified with 1-amino-10-undecene was reacted with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in toluene. Two possible competing reactions for PCBM, via the ester group and by direct attachment to the C60 portion, are analyzed. X-ray photoelectron spectroscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, and time-of-flight secondary ion mass spectroscopy, supplemented by density functional theory calculations, suggest that despite the similarity of the energetics for those two reaction pathways, predominant chemisorption occurs via the direct attachment of the C60 cage to the primary amino group of the functionalized silicon surface.

Carbon Nanotubes Covalently Attached to Functionalized Surfaces Directly through the Carbon Cage

“…40 The main peak in Figure 9a confirms that this is indeed the case. It should, however, be pointed out that the intensity of this feature is very small compared to the peak for the same sample in Figure 8, suggesting that only a part of this reaction occurs through the amide functionality and a substantial portion leads to a direct attachment of the primary amino group to the cage of the carbon nanotube.…”

“…This calibration approach has been demonstrated to provide reproducible binding energies for N-containing functional groups to be used for the assessment of surface chemical reactions. 39,40,56,57 …”

Conformational Transitions of Phase-Separated Binary Molecules Assisted by Surface Dehalogenation

“…In addition, amino (−NH 2 ) is one of the most commonly used anchoring groups in molecular junctions . Amino-group-terminated organic thin films are ideal functional chemical platforms for hosting protein and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in the production of immunoassay-based diagnostic devices and solar cells, respectively. In this article, we choose hexabromobenzene (HBB) and melamine (1,3,5-triazine-2,4,6-triamine) as the model system for studying the cooperative effect of the −NH 2 group and bromine adatoms on the molecular conformational transition and packing geometry.…”

Monolayer of Hydrazine Facilitates the Direct Covalent Attachment of C60 Fullerene to a Silicon Surface

“…It is also fully consistent with the previous investigations of amino-modified buckyballs. 26,28,29 Thus, the feature at 399.6 eV in Figure 6 belongs to the unreacted nitrogen-containing surface sites; the peak at 400.3 eV corresponds to the nitrogen atoms connected to silicon and the C 60 cage. This assignment is also supported by the DFT studies summarized in Figure 6.…”

“…For example, the reactivity of the amine-functionalized silicon surfaces has been explored for thin film deposition 21−23 and metallic nanostructure formation. 24,25 At the same time, as mentioned above, the versatility of the primary amine group in attachment reactions with buckminsterfullerene C 60 15,26−28 or their derivatives 29 has been demonstrated for amine-terminated organic monolayers on silicon 15,29 or gold substrates, 26−28 where the direct dissociative attachment of −NH 2 to the cage of the carbon structure has been the major reaction pathway. However, the controlled formation of a direct organic− inorganic interface between silicon and carbon structures in a nonvacuum environment has remained elusive.…”