Time-of-flight secondary ion mass spectrometry investigations of self-assembled monolayers of organic thiols, sulfides, and disulfides on gold surfaces

Surface mass spectrometry of molecular species

“…Isotopic analysis of the SIMS peak at m/z 227 was not possible owing to the abundance of signal at adjacent masses: this peak was only identified by comparison with SIMS spectra of similar compounds. 126 SIMS also displays peaks at m/z 270 and 300 that derive from the biotinylated thiolate. Au C appears in all spectra at m/z 197.…”

The Chemistry of Self-Assembled Long-Chain Alkanethiol Monolayers on Gold

“…In studies specifically dealing the self-assembled films (102). Hagenhoff et al used timewith alkanethiol monolayers, the calculations are built of-flight secondary ion mass spectrometry to show that the around three different types of Monte Carlo ''moves''; transadsorption of disulfides to the gold substrates requires the lation displacements are treated in a standard way, rotations cleavage of the s-s bond, and the molecules bind to the are handled by the method of Barker and Watts, and conforsubstrate as monomers, resulting in the same surface compomations of the chain molecules are sampled by the configusition as for thiol (103). rational bias Monte Carlo (CBMC) scheme (95).…”

Surface and Adsorption Structures of Dialkyl Sulfide Self-Assembled Monolayers on Au(111)

“…[7][8][9][10] In particular, to understand fundamental aspects such as structures and self-assembly processes, the SAMs prepared by alkanethiols or dialkyl disulfides on gold have been extensively studied by a variety of surface characterization techniques. [11][12][13][14][15][16][17][18][19][20][21] As a result, it is generally believed that adsorption of dialkyl disulfides on gold occurs via S-S bond cleavage and alkanethiols adsorb via S-H bond cleavage. Therefore, both compounds on gold form identical SAMs consisting of gold-bound thiolates.…”

“…12,14,32,[39][40][41] This difference in lattice structure may be due to different adsorption mechanisms between dialkyl sulfides and alkanethiols or dialkyl disulfides, as revealed in previous studies. 18,25,[27][28][29][30]32 Because two alkyl chains positioned at one sulfur atom are structurally confined due to the intact adsorption of dialkyl sulfides on gold, a change in the tilt and twist angles of alkyl chains in the packing structure of the monolayer would be expected as a result of the spatial rearrangement of alkyl chains in two-dimensional ordering process, resulting in the different lattice structures.On the other hand, we should note that the observed structure for DOS SAMs on Au (111) is the result of the optimization of the SAM preparation procedures. It has been pointed out that the results on dialkyl sulfide SAMs show poor reproducibility because of uncontrollable experimental conditions such as degree of surface contamination, purity of the substance, and small fluctuations of temperature, which are of crucial importance for the quality of physisorbed dialkyl sulfide SAMs.…”