Selenium, Benzeneselenol, and Selenophene Interaction with Cu(100)

Abstract

A high-resolution synchrotron photoemission study of selenium, selenophene (Seph), and benzeneselenol (BSe) adsorption on a Cu(100) surface was performed, to investigate the film structure, chemical adsorption properties, and molecular orientation. Complementary measurements for selenophene adsorption on Au(111) were also performed. The investigation is based on determination of core level binding energies (CLBEs) by X-ray photoelectron spectroscopy (XPS) and near-edge adsorption fine structure (NEXAFS). Se chemisorption was studied as a complement to the work on molecules in order to obtain data on the CLBEs for the atomic case. Se adsorption was performed from a Na2Se solution and thereafter annealing in vacuum. Annealing leads to appearance of ordered structures in LEED. Se 3d CLBEs were determined for the different cases. Fits of Se 3d XPS spectra show existence of several components attributable to different adsorption configurations. Also coadsorption with S was studied, which leads to changes in adsorption configurations depending upon the coadsorption procedure: simultaneous or preadsorption of S. Annealing after simultaneous adsorption leads to S elimination, while it is retained after preadsorption suggesting a higher reactivity of Se. In the case of both BSe and selenophene, XPS spectra indicate that Se–C bond scission occurs, which leads to appearance of some atomic Se on the surface and coadsorption of molecules. This is accompanied by attenuation of characteristic aromatic ring peaks in NEXAFS. In the case of selenophene single Se–C bond scission leads to appearance of alkenechain selenol molecules bound with the Se atom to the surface. A similar situation is encountered for selenophene on Au(111). NEXAFS did not show dichroism possibly partly because of dissociation processes.

Stand-Alone CuFeSe2 (Eskebornite) Nanosheets for Photothermal Cancer Therapy

“…As shown in Figure S5 , the XPS spectra of both as-synthesized CuFeSe 2 nanosheets and the CFS-S nanosheets exhibit Cu 2p with two peaks at 932.4 eV and 952.3 eV, and Fe 2p with two peaks at 711.1 eV and 724.8 eV, suggesting the redox states of Cu and Fe elements to be +1 and +3, respectively [ 26 , 27 ]. Structures related to Se 3d and Se 3p can be observed at around 54 eV, 160.2 eV and 165.8 eV, which is in good agreement with the peaks of Se 2− [ 26 , 28 ]. The S 2p with a peak at 162.7 eV presented in the XPS spectrum of CFS-S corresponds to S 2p 1/2 , which is consistent with a valence of −2, proving the presence of S 2− in the CFS-S nanosheets [ 12 ], where the content of S 2− in CFS-S was evaluated to be around 14.6% in atomic percentage.…”

III–VI and IV–VI van der Waals Semiconductors InSe, GaSe and GeSe: A Suitable Platform for Efficient Electrochemical Water Splitting, Photocatalysis and Chemical Sensing

“…Upon a prolonged exposure of one year in air, an increment of the spectral contribution of Ga 2 O 3 was revealed, with the appearance of a new component associated to mixed oxidehydroxide Ga 2 O 3-x (OH) y species. [84][85][86] No relevant changes exist in the Se-3d core level, in which a new component due to Se(0) and the component of SeÀ Se aggregates [87][88][89] as byproducts of Ga 2 Se 3 oxidation via 2Ga 2 Se 3 + 3O 2 !2Ga 2 O 3 + 6Se [74] was found. Accordingly, the thickness of gallium-oxide of about 0.8 nm was estimated.…”

Synthesis and Applications of Organic Selenols

“…Both aromatic [105][106][107][108][109][110] and aliphatic [103,104] selenols have been successfully employed. The synthesis and the physicochemical properties of alkaneselenol- [111,112] and benzeneselenol- [113] derived SAMs on Cu(100) surfaces, as well as the stability of n-dodecanethiol SAMs on Cu in the presence of competing n-dodecaneselenol, [114] have also been investigated.…”