Ultraviolet photoelectron spectroscopy polymers

Interpretations of the early stages of metallization of PMDA-ODA are controversial, but the data are more extensive than for polystyrene. PMDA-ODA has been featured for use in integrated circuit fabrication and lately, for mapping the engineering (57), physics and chemistry of polymer metallization (58). Many analysts of XPS, ultraviolet photoelectron spectroscopy (UPS), near edge... 

The problem of adhesion between a polymer and a metal is strongly dependent on the specific type of polymer and metal involved, as well as on the deposition process under which the interface between the two is formed. In order to improve adhesion, different pretreatment methods can be used, but the development of such techniques requires detailed information about metal-polymer interfaces. Particularly, in the case of thin metal films deposited by physical vapor deposition (PVD) in ultra high vaccum (UHV), X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) have been used to obtain chemical information about initial film growth modes,... 

Intermolecular relaxation effects are a central issue in the interpretation of the ultraviolet photoelectron spectroscopy (UPS) of molecular solids. These relaxation effects result in several significant characteristics of UPS valence spectra, intermolecular relaxation phenomena lead to localized electron molecular-ion states, which are responsible for rigid gas-to-solid molecular spectral energy shifts, spectral line broadening, and dynamic electronic localization effects in aromatic pendant group polymers. 

Salaneck, W.R. and Eahhnan, M., Hybrid interfaces of conjugate polymers Band edge ahgnment studied by ultraviolet photoelectron spectroscopy, J. Mater. Res., 19, 1917, 2004. 

The direct mapping of the electronic structure of the conjugated polymers is possible in photoelectron spectroscopy of thin films. The valence band, which is available from ultraviolet photoelectron spectroscopy, clearly shows shifts as well as a reduction of photoelectron peaks coming from the frontier k orbitals [31—33]. This is consistent with predictions from calculations using a Valence Effective Hamiltonian using a model of conformational twists separating every dimer on the chain. 

While many spectroscopic studies have been published on dimers, the most extensive polymer studies have been with Ag, Na, and Cu clusters. As might be expected much of the interest in silver relates to the photographic process where it appears that a four-atom silver cluster on a silver halide surface leads to reduction by developer, whereas a three-atom cluster does not. The electron spin resonance (ESR) spectrum of sodium in argon confirms that the trimer is covalently bonded and not an equilateral triangle. Ultraviolet photoelectron spectroscopy (UPS) of Cu clusters indicates that the d band is separate from the s band, unlike in the bulk or in the Xa calculations mentioned earlier. 

The electronic and chemical structure of poly(67) was studied experimentally by X-ray and ultraviolet photoelectron spectroscopy, and theoretically by quantum-chemical calculations [122]. X-ray spectroscopy showed that the thin films were chemically pure with no oxygen present. The remarkably well-resolved S2p spectrum indicated the quality of the polymer material to be excellent (minimum of chemical and spatial... 

Salaneck, W.R. (2009) Classical ultraviolet photoelectron spectroscopy of polymers. J. Electr. Spectrosc. Related Phenomena, 174, 3,... 

By producing PPy films, electrical conductivities up to 150 S/cm can be obtained. Electropolymerized PPy films differ in their molecular structure according to polymerization conditions such as the electrochemical parameters of the polymerization. At low current densities (l.c.d.) below 3 mA/cm one-dimensional polypyrrole chain structures are mainly produced [3]. Higher current densities predominantly lead to two-dimensional molecular polymer structures. The electronic state of such PPy films produced with high current density (h.c.d.) has been investigated by several solid-state spectroscopic methods such as ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS), as well as temperature-dependent electrical conductivity measurements [4-6]. 

The plasma polymerization of TCl JQ and TCNE was carried out at 13.56 MHz from the gas phase and semiconductive polymeric films were obtained [88, 89]. The electrical conductivities of the films obtained ranged fix m 10 " to 10 S cm and the Al/polymer/ITO (indium tin oxide) sandwich cells made from the films showed rectifying behavior and photovoltaic response. Photoconductivity was also observed in the films. Infrared, ultraviolet, and X-ray photoelectron spectroscopy were utilized to characterize the structure, and these results as well as those from electrical measurements confirmed that a conjugated structure with delocalized 7c-electrons has been formed in the films. 

Teare, D.O.H., Ton-That, C., and Bradley, R.H. (2000) Surface characterization and ageing of ultraviolet-ozone-treated polymers using atomic force microscopy and X-ray photoelectron spectroscopy. Surf. Interface Anal., 29 (4), 276-283. 

Microscopy (TEM), UltraViolet-Visible (UV-vis) Spectroscopy, Nuclear Magnetic Resonance (NMR) Spectroscopy, and Fourier Transform Infrared (FTIR) Spectroscopy are among others deeply used and X-ray Photoelectron Spectroscopy (XPS) has become an increasingly available and powerful tool for imderstanding the nature of different surfaces and chemical and electronic structure of functionalized molecules or polymers upon coordination for example of metallic nanoparticles or biological systems. 

Three of the most direct and readily comprehensible measures of the electronic structure of a molecular system are optical absorption spectroscopy and the two branched of photoelectron spectroscopy, known as ultraviolet and X-ray photoelectron spectroscopy, or UPS and XPS. The XPS of polymers [51], the UPS of polymers [52], as well as both the XPS and UPS of conducting polymers [53] have been reviewed recently. The reader is referred to the literature for further details. It should be relatively obvious from the figures presented below, however, how the calculated band structure, the density-of-valence-states (DOVs) derived therefrom, and the corresponding experimental valence band spectra can be compared with one another. 

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