The three nitrogen peaks detected in the XPS N1s spectra were assigned to amine/amide (400.5 eV) and azide (402.1 and 405.6 eV) species. Here, the challenge of characterizing the PFPA modified surfaces was addressed by detailed XPS experimental analyses. Upon light irradiation, the azido group in PFPA is converted to a highly reactive singlet nitrene species that readily undergoes CH insertion and C=C addition reactions. It is a simple route for the efficient immobilization of graphene, proteins, carbohydrates and synthetic polymers onto a variety of surfaces. PFPA chemistry is a novel immobilization method for tailoring the surface properties of materials. Smart, Resolving Surface Chemical States in XPS Analysis of First Row Transition Metals, Oxides and Hydroxides: Sc, Ti, V, Cu and Zn, Applied Surface Science, 257 (2010) 887-898.X-ray Photoelectron Spectroscopy (XPS) was used to characterize the nitrogen species in perfluorophenylazide (PFPA) self-assembled monolayers.
#XPS PEAK FWHM SERIES#
Smart, Quantitative Chemical State XPS Analysis of First Row Transition Metals, Oxides and Hydroxides, IVC-17/ICSS-13 and ICN+T2007, Stockholm July 2-6, 2007, Journal of Physics: Conference Series 100, 012025 (2008). Rumble, NIST Standard Reference Database 20, Version 3.4 (web version) (http://xps/) 2003. Spectral fitting parameters for Ti 2p: binding energy (eV), percentage of total area, FWHM value (eV) for each pass energy, and spectral component separation (eV). Literature values (from ) for Ti 2p3/2 spectra. Ti 2p spectrum of a heat-treated Ti-apatite composite using peak fittings derived from Tables 1 and 2. A CasaXPS ready (.vms file) of mixed titanium species can be downloaded here. Further information and expanded discussion can be found in reference.
The FWHM’s for Ti(II) (at a BE of 455.4 eV) and Ti(III) (at a BE of 457.2 eV), which are likely structurally loosely ordered, are constrained to have equal width to each other and are generally slightly broader than the well ordered Ti(IV) oxide peaks. The FWHM’s for the metal and Ti(IV) peaks are derived from the standard sample analyses. The intensity ratio of the Ti 2p3/2 and Ti 2p1/2 peaks are also constrained to 2:1. The Ti 2p1/2 peak for each species is constrained to be at a fixed energy above the Ti 2p3/2 peak. This removes the uncertainty associated with charge correcting to adventitious C especially in situations where the adventitious overlayer is not in good electrical contact with the titanium containing species underneath. Although C 1s set to 284.8 eV can be used as an internal charge correction it is also possible in this case to use the Ti 2p3/2 metal peak set at 453.7 eV or the clearly defined Ti(IV) (TiO2) 2p3/2 peak set at 458.6 eV. An example of the use of these parameters is presented for a mixed oxidation state titanium-containing sample in Figure 1. As well, data from readily available standard samples (metal, TiO2) were used to clarify the peak-widths, splitting (Δ=6.05 eV for Ti(0), Δ=5.72 eV for Ti(IV)) and shapes (asymmetric for the metallic component) (Table 2). Initial fitting parameters for the titanium 2p peak were developed using averaged binding energy (BE) data and 2p1/2 – 2p3/2 splitting data from the NIST XPS Database (Table 1).
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