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In this work, electrochromic devices were prepared using the redox couple ethyl viologen diperchlorate and 1,1′-diethyl ferrocene in propylene carbonate as an aprotic solvent to facilitate ions separation and diffusion inside the devices. Electrochromic devices were made using electrochromic gel mixtures at the concentrations of 55%, 60% and 65% with respect to the bisphenol A polymer. In particular, two sets of gels were made: one set contained the bisphenol A not-polymerized while and the second one contained the polymerized polymer. Different techniques, such as cyclic voltammetry, UV-vis-NIR, and Raman spectroscopy, were used to study such systems to understand the differences in terms of performances between the different sets of electrochromic devices. Cyclic voltammetry confirmed that the oxidation process of the 1,1′-diethyl ferrocene and the reduction of the ethyl viologen diperchlorate occurred at about 0.4 V. Interesting variations in the transmittances were found between the two groups of samples. The best values of CE were provided by the electrochromic devices based on the polymerized electrochromic gel mixture at a concentration of 60% (EM60). The EM60 device result was CE = 92.82 C/cm2 in the visible region and CE = 80.38 C/cm2 in the near–infrared region, confirming that these devices can be used for energy-saving applications. A structural characterization of the materials used in the two sets of electrochromic devices was made using Raman spectroscopy, and the analysis supports the electrochemical models used to explain the processes involved during operation of the electrochromic systems. [ABSTRACT FROM AUTHOR]

Raman spectroscopy plays a pivotal role in spectroscopic investigations. The small Raman scattering cross-section of numerous analytes, however, requires enhancement of the signal through specific structuring of the electromagnetic and morphological properties of the underlying surface. This enhancement technique is known as surface-enhanced Raman spectroscopy (SERS). Despite the existence of various proposed alternatives, the approach involving Fabry–Pérot cavities, which constitutes a straightforward method to enhance the electromagnetic field around the analyte, has not been extensively utilized. This is because, for the analyte to experience the maximum electric field, it needs to be embedded within the cavity. Consequently, the top mirror of the cavity will eventually shield it from the external laser source. Recently, an open-cavity configuration has been demonstrated to exhibit properties similar to the classic Fabry–Pérot configuration, with the added advantage of maintaining direct accessibility for the laser source. This paper showcases how such a simple yet innovative configuration can be effectively utilized to achieve remarkable Raman enhancement. The simple structure, coupled with its inexpensive nature and versatility in material selection and scalability, makes it an ideal choice for various analytes and integration into diverse Raman apparatus setups. [ABSTRACT FROM AUTHOR]

In this work, the implementation of an electrochromic device (10 cm × 10 cm in size) for energy saving applications has been presented. As electrochromic system has been used with an electrochromic solution (ECsol) made by ethyl viologen diperchlorate [EV(ClO4)2], 1,1′-diethyl ferrocene (DEFc) and propylene carbonate (PC), as solvent. The final system has been obtained by mixing the ECsol, described above, with a polymeric system made by Bisphenol-A glycerolate (1 glycerol/phenol) diacrylate (BPA) and 2,2-Dimethoxy-2-phenylacetophenone (Irgacure 651) in a weight percentage equal to 60:40% w/w, respectively. Lithography has been used to make a spacer pattern with a thickness of about 15–20 µm between the two substrates. Micro-Raman spectroscopy confirmed the presence of the EV•+ as justified by the blue color of the electrochromic device in the ON state. Electrochemical and optical properties of the electrochromic device have been studied. The device shows reversible electrochromic behavior as confirmed by cyclic color variation due to the reduction and oxidation process of the EV2+/EV•+ couple. The electrochromic device shows a variation of the % transmittance in the visible region at 400 nm of 59.6% in the OFF state and 0.48% at 3.0 V. At 606 nm the transmittance in the bleached state is 84.58% in the OFF state and then decreases to 1.01% when it is fully colored at 3.0 V. In the NIR region at 890 nm, the device shows a transmittance of 74.3% in the OFF state and 23.7% at 3.0 V while at 1165 nm the values of the transmittance changed from 83.21% in the OFF state to 1.58% in the ON state at 3.0 V. The electrochromic device shows high values of CCR% and exhibits excellent values of CE in both visible and near-infrared regions when switched between OFF/ON states. In the NIR region at 890 nm, electrochromic devices can be used for the energy-saving of buildings with a promising CE of 120.9 cm2/C and 420.1 cm2/C at 1165 nm. [ABSTRACT FROM AUTHOR]

The present work was a part of pre conservation treatment investigation. Micro-Raman Spectroscopy has been used for the characterization of a specimen belonging to the frame of the Gilcrease Museum oil painting "White Man's Buffalo" by the artist Charles M. Russell. The main components of the Van Dyck Brown pigment (VDK) such as hematite (Fe2O3), α-goethite (α-FeOOH), amorphous carbon, and humic substances were identified by using two different excitation sources (514 and 633 nm). Traces of hematite and intercalated barite (BaSO4) were found and could come from the Armenian Bole that is commonly used in the water gilding technique of gold leaf. The use of a protein-organic binding medium such as rabbit-skin glue was indicated. [ABSTRACT FROM AUTHOR]

In this study, polyelectrolyte (PE) layers are deposited on substrates made by glass covered with an array of gold nanoparticles (GNPs). In particular, the samples studied have 0 PE layers (GGPE 0 ), 3 PE layers (GGPE 3 ), 11 PE layers (GGPE 11 ), and 21 PE layers (GGPE 21 ). All samples have been studied by micro-Raman spectroscopy. An acetic acid solution (10% v/v) has been used as a standard solution in order to investigate the SERS effect induced by different numbers of PE layers in each sample. The Surface Enhancement Raman Spectroscopy (SERS) effect correlating to the number of PE layers deposited on the samples has been shown. This effect is explained in terms of an increase in the interaction between the photon of the laser source and the plasmonic band of the GNPs due to a change of the permittivity of the surrounding medium around the GNPs. The trends of the ratios of the intensities of the Raman bands of the acetic acid solution (acetic acid and water molecules) on the band at 1098 cm − 1 ascribed to the substrates increase, and the number of PE layers increases. [ABSTRACT FROM AUTHOR]

This study was carried out on a crucifix located inside the church of St. Mary Major in Acri. The story of this crucifix is not very clear, and its dating is still uncertain, as well; however, it ranges between the 15th and the 14th century. The wooden sculpture of the crucified body of Jesus was painted and the conservation state of the color appeared good. A detailed analysis of the pigments was considered very useful in verifying the restoration history of this crucifix, and to discriminate between the original painting and later restoration activities. A micro-Raman analysis reveals the presence of the classical pigments expected for the estimated age of the crucifix, such as gypsum, terra di Siena, vermilion, carbon black, and others. In addition, other pigments of more recent use were found, such as Prussian blue, titanium white, lithopone, and chromium yellow, mostly in the thong around body of Jesus, which appears green. This is a clear indication of a relevant modification of the artifact in modern times, when the thong was totally painted again; smaller modifications were surely revealed by the presence of "modern" pigments on other points of the body. [ABSTRACT FROM AUTHOR]

This work describes the electrochemical properties of a type of PMMA-based gel polymer electrolytes (GPEs). The gel polymer electrolyte systems at a concentration of (20:80) % w/w were prepared from poly (methyl methacrylate), lithium perchlorate LiClO4 and single plasticizer propylene carbonate (PMMA-Li-PC) and a mixture of plasticizers made by propylene carbonate and ethylene carbonate in molar ratio 1:1, (PMMA-Li-PC-EC). Different salt concentrations (0.1 M, 0.5 M, 1 M, 2 M) were studied. The effect of different plasticizers (single and mixed) on the properties of gel polymer electrolytes were considered. The variation of conductivity versus salt concentration, thermal properties using DSC and TGA, anodic stability and FTIR spectroscopy were used in this study. The maximum ionic conductivity of σ = 0.031 S/cm were obtained for PMMA-Li-PC-EC with a salt concentration equal to 1 M. Ion-pairing phenomena and all ion associations were observed between lithium cations, plasticizers and host polymers through FTIR spectroscopy. The anodic stability of the PMMA-based gel polymer electrolytes was recorded up to 4 V. The glass temperatures of these electrolytes were estimated. We found they were dependent on the plasticization effect of plasticizers on the polymer chains and the increase of the salt concentration. Unexpectedly, it was determined that an unreacted PMMA monomer was present in the system, which appears to enhance ion conduction. The presence and possibly the addition of a monomer may be a technique for increasing ion conduction in other gel systems that warrants further study. [ABSTRACT FROM AUTHOR]

Until now, the ability to form a self-assembled monolayer (SAM) on a surface has been investigated according to deposition techniques, which in turn depend on surface-coater interactions. In this paper, we pursued two goals: to form a SAM on a gold nanosurface and to correlate its formation to the nanosurface curvature. To achieve these objectives, gold nanoparticles of different shapes (spheres, rods, and triangles) were functionalized with a luminescent thiolated bipyridine (Bpy-SH), and the SAM formation was studied by investigating the photo-physics of Bpy-SH. We have shown that emission wavelength and excited-state lifetime of Bpy-SH are strongly correlated to the formation of specific aggregates within SAMs, the nature of these aggregates being in close correlation to the shape of the nanoparticles. Micro-Raman spectroscopy investigation was used to test the SERS effect of gold nanoparticles on thiolated bipyridine forming SAMs. [ABSTRACT FROM AUTHOR]

Graphene oxide and reduced graphene oxide thin films are very promising materials because they can be used in optoelectronic devices and in a growing range of applications such as touch screens and flexible displays. In this work, graphene oxide (GO) and thermally reduced graphene oxide (rGO) thin films, deposited on Ti/glass substrates, have been obtained by electrophoretic deposition. The morphological and the structural properties of the samples have been investigated by micro-Raman technique, X-ray reflectometry, and SEM analysis. In order to study the optical and electrical properties, variable angle spectroscopic ellipsometry and impedance analysis have been performed. The thermal annealing changes strongly the structural, electrical, and optical properties, because during the thermal processes some amount of sp³ bonds originally present in GO were removed. In particular, the annealing enhances the Ohmic behavior of the rGO film increasing its conductivity and the estimated optical density. Moreover, using electrophoretic deposition, we have found a higher value of optical density for GO thin films, not observed in GO films obtained with other deposition methods. [ABSTRACT FROM AUTHOR]

Lead zirconium titanate PbZr0.53Ti0.47O3 (PZT) thin films have been obtained by sol-gel synthesis, deposited on different substrates [float glass, indium tin oxide (ITO)-coated float glass, and intrinsic silicon wafer], and later subjected to different thermal treatments. The morphologic and the structural properties of both PZT thin films and substrates have been investigated by scanning electron microscope and their composition was determined by energy dispersive x-ray (EDX) analysis. Moreover, variable angle spectroscopic ellipsometry provides relevant information on the electronic and optical properties of the samples. In particular, the optical constant dispersion of PZT deposited on ITO-coated float glasses shows a small absorption resonance in the near IR region, not observed in PZT films deposited on the other substrates, so that such absorption resonance can be explained by interfacial effects between ITO and PZT layers. This hypothesis is also supported by EDX measurements, showing an interdiffusion of lead and indium ions, across the PZT-ITO interface, that can generate a peculiar charge distribution in this region. [ABSTRACT FROM AUTHOR]

The solvation mechanism of lithium ions in pure ethylene carbonate (EC) solutions has been studied in a wide concentration range by different techniques and for temperatures up to 100 °C. For low concentrations (R = [Li[sup +] ]/[EC] ≤ 0.1) the solvation number of Li[sup +] cations in the solution has been found to be ∼7, by using nuclear magnetic resonance techniques. This number decreases at higher concentration, and complexes Li[sup +]-EC with ∼3 solvent molecules per cation are formed when R =0.33. The temperature dependence of the solvation has been investigated for the more concentrated solutions by Raman spectroscopy. When the temperature increases, the relative intensity of the Raman bands upshifted by the lithium interaction also increases remarkably, indicating that Li[sup +] ions form complexes with a higher solvation number. On the other hand, a higher degree of reassociation of Li[sup +] cations with perchlorate anions is observed. [ABSTRACT FROM AUTHOR]

Thermoreversible polymer gel electrolytes with ionic conductivities of about 10[SUP-3] S cm[SUP-1] at room temperature, were prepared from poly(acrylonitrile) (PAN)-ethylene carbonate (EC)-LiClO[SUB4] at different solvent/salt ratios. A temperature dependence was investigated for the electrical and mechanical properties, as well as for spectroscopic changes associate to the solvation mechanism of lithium ions in these gel. The measurements performed on this system concern ionic conductivity, study of self-diffusion coefficient by [SUP1]H-NMR, Raman spectroscopy and, finally, an accurate analysis of its mechanical proprieties by rheological tests. The gels present a strong-weak gel transition at about 70 °C, independent from salt concentration hence assignable only to the polymeric matrix. However, this transition is completely reversible on cooling, being this a necessary mechanical property for industrial applications. The Raman study has pointed out an increase, on heating, of the Li[SUP+] coordination number by EC molecules, as well as a growing number of lithium ions involved in the ionic association (Li[SUP+]-solvent-ClO[SUB4]) and in the Li[SUP+]-CN interaction. The experimental evidences suggest an evolution of the system toward a less organized, weak gel configuration, when temperature rises above 65 °C. [ABSTRACT FROM AUTHOR]

The synthesis, morphologic and the structural properties of lead zirconium titanate Pb[Zr.sub.0.53][Ti.sub.0.47][O.sub.3] (PZT) thin films deposited on different substrates such as float glass, indium tin oxide (ITO)-coated float glass, and intrinsic silicon wafer are described. A small absorption resonance in the near infrared (IR) region observed for the optical constant dispersion of PZT deposited on ITO-coated float glasses is explained by interfacial effects between ITO and PZT layers.

Ultraviolet absorption and micro-Raman analyses are used for studying the polymorphism in the growth of titanyl phthalocyanine films on dielectric substrates. Hyperthermal beams have given unprecedented control on the growth, which has produced crystalline films with a controlled structure and different phases even at room temperature and on amorphous substrates, depending on the deposition rate.

Abstract: In the aim to get high quality graphene films, with large domains and free from impurities, minimizing also the manufacturing costs, we investigate the graphene grown on copper (Cu) foil by chemical vapor deposition at ambient pressure conditions, by using methane (CH4) as carbon source, diluted in a suitable mixture of argon (Ar) and hydrogen (H2). Several graphene samples were synthesized, for variable exposure times to hydrocarbon precursor, in the range from 1 min to 1 hr. The quality of the graphene films and their structural, morphological, and electronic properties were evaluated by micro‐Raman spectroscopy and other techniques, including, scanning tunneling microscopy, atomic force microscopy, and scanning electronic microscopy. In particular, samples obtained with shorter growth time (less than 10 min) exhibit a non‐uniform coverage of the Cu surface, whereas those synthesized with exposure time between 10 and 30 min show a prevalence of well‐ordered monolayer graphene domains. For longer deposition, the amount of disordered domains increases, as revealed by Raman analysis, and the resulting film shows a nonself‐limiting growth behavior for chemical vapor deposition at atmospheric conditions. In addition, we observed 2 kinds of monolayer graphene, in terms of coupling with the Cu surface, for the samples synthesized between 10 and 30 min. To the best of our knowledge, “coupled” and “decoupled” graphene regions have never been reported at the same time on Cu surface. Furthermore, a Raman statistical analysis has been performed on the G and 2D bands measured in both the kinds of regions, gaining evidence of a bimodal behavior for the graphene spots, corresponding to “coupled” and “decoupled” configurations. This difference, which is appreciable also by the optical microscopy inspection, could be related to the local Cu oxidation and to oxygen intercalation after graphene growth. [ABSTRACT FROM AUTHOR]

Micro-Raman Spectroscopy was used to determine the orientation of the E7 nematic liquid crystal molecules inside the POLICRYPS (POlymer LIquid CRYstal Polymer Slices) holographic gratings. The POLICRYPS grating was analyzed after defining the Raman features of each single component of the system: i.e the random aligned nematic liquid crystal E7 and Norland Optical Adhesive (NOA-61). Among the Raman bands of the liquid crystal molecules, a specific one was selected, which exhibits strong anisotropy of the Raman tensor. The modulation of its intensity, depending on the sample orientation with respect to the laser polarization, provided the experimental evidence about the orientation of the E7 molecules, which occurred to be perpendicular to the polymeric slices. [ABSTRACT FROM AUTHOR]

Thin films of lead zirconate titanate (PZT) were obtained by a modified sol-gel route on float glass and indium tin oxide (ITO)-covered float glass substrates. Different thermal treatments were performed on the deposited films in the temperature range 100-700°C. Spectroscopic ellipsometry was used to investigate the optical properties of the deposited films, and the changing optical absorption spectra were interpreted in terms of the growth of two different crystal phases, pyrochlore and ferroelectric perovskite, as a function of annealing temperature. Moreover, a specific resonance at 1.9 nm was detected when thin PZT films are deposited on ITO substrates and was attributed to a particular charge distribution at the interface. Finally, the performance in rectifying the electro-optical response of asymmetric nematic liquid crystal cells was tested for some of the films undergoing different thermal treatments. [ABSTRACT FROM AUTHOR]

Electrical properties of ferroelectric films are influenced by factors that include methods of synthesis and characteristics of the substrate electrode. Conductivity measurements were performed on PZT (lead zirconate titanate) thin films deposited by sol-gel synthesis on a copper electrode to investigate electric properties and isolate the principal charge carriers. A semiconducting PZT/Cu interface appears during thermal treatment, significantly influencing electric conduction. A power law, describing the transport mechanism across the PZT film, was found empirically. [ABSTRACT FROM AUTHOR]

PbZr0.53Ti0.47O3 (PZT) thin films were obtained by sol-gel synthesis, deposited by spin coating on ITO-coated float glass and Si wafer, and subjected to different thermal treatments. Their thermal structural evolutions have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The growth of ferroelectric perovskite phase, occurring for the highest annealing temperatures, depends on the substrate, being observed only on ITO substrate, while pyroclore phase, not ferroelectric, grows on Si substrates. The electrical properties of the perovskite phase have been investigated, on the nanoscale, by using electric force microscopy (EFM). It reveals asymmetric responses for induced polarization persistence, which can be related to phenomena of intrinsic polarization regarding the films, which changes as a function of the annealing temperature and of the duration of the annealing processes. [ABSTRACT FROM AUTHOR]

A collection of archaeological iron artifacts, whose age could be assigned from the Iron Age up to the post–medieval period, and coming from the Archaeological National Museum of Crotone (Calabria, Italy) were investigated. They show evident forms of degradation although they were restored around twenty years ago. The aim of this work was to study the chemistry of the corrosion layers formed on the iron artifacts. Techniques such as optical and electronic microscopies (OM and SEM-EDS), X-Ray diffraction (XRD), Ion Chromatography, ATR/FTIR Spectroscopy and Micro-Raman Spectroscopy have been applied. It was found that corrosion products are mainly made up of goethite, maghemite, magnetite, hematite, lepidocrocite and ferrihyidrite. Akaganeite was often found at the interface between the corrosion products and the core of the metal. This could be considered as the main cause of the rapid post-restoration deterioration of iron objects investigated. [ABSTRACT FROM AUTHOR]