Dubravka Peić Čaldarović, Nikša Stančić, Povijest hrvatskoga grba: Hrvatski grb u mijenama hrvatske povijesti od 14. do početka 21. stoljeća, Zagreb: Školska knjiga, 2011., 316 str.

A series of para-oligophenylene mono- and dicarboxylic acids (R-(C6H4)nCOOH, n=1-3, R=H,COOH) was studied. Adsorbed on Au(111)/mica modified by an underpotential deposited bilayer of Ag, the self-assembled monolayers (SAMs) were analysed by near edge X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy and scanning tunneling microscopy. In all cases SAMs are formed with molecules adopting an upright orientation and anchored to the substrate by a carboxylate. Except benzoic acid, all SAMs could be imaged at molecular resolution, which revealed highly crystalline layers with a dense molecular packing. The structures of the SAMs are described by a rectangular (5×√3) unit cell for the prevailing phase of the monocarboxylic acids and an oblique (√93×√133) unit cell for the dicarboxylic acids, thus, evidencing a pronounced influence of the second COOH moiety on the SAM structure. Density functional theory calculations suggest that hydrogen bonding between the SAM terminating COOH moieties accounts for the difference. Contrasting other classes of SAMs, the systems studied here are determined by intermolecular interactions whereas molecule-substrate interactions play a secondary role. Thus, eliminating problems arising from the mismatch between the molecular and substrate lattices, coordinatively bonded carboxylic acids on silver should provide considerable flexibility in the design of SAM structures

Evidence of Strong Electron Correlations in Gamma-Iron

Single-particle excitation spectra of gamma-Fe in the paramagnetic state have been investigated by means of the first-principles dynamical coherent potential approximation theory which has recently been developed. It is found that the central peak in the density of states consisting of the t2g bands is destroyed by electron correlations, and the Mott-Hubbard type correlated bands appear. The results indicate that the gamma-Fe can behave as correlated electrons at high temperatures.Comment: 7 pages, 3 figures, to be published in J. Phys. Soc. Jpn. Vol.78, No.9 (2009

Novel synthesis and electrochemical investigations of ZnO/C composites for lithium-ion batteries

For the first time, ZnO/C composites were synthesized using zinc glycerolate as a precursor through one-step calcination under a nitrogen atmosphere. The effect of the heat treatment conditions on the structure, composition, morphology as well as on the electrochemical properties regarding application in lithium-ion batteries are investigated. The products obtained by calcination of the precursor in nitrogen at 400—800 °C consist of zinc oxide nanoparticles and amorphous carbon that is in-situ generated from organic components of the glycerolate precursor. When used as anode material for lithium-ion batteries, the as-prepared ZnO/C composite synthesized at a calcination temperature of 700 °C delivers initial discharge and charge capacities of 1061 and 671 mAh g−1 at a current rate of 100 mA g−1 and hence 1.5 times more than bare ZnO, which reaches only 749/439 mAh g−1. The native carbon improves the conductivity, allowing efficient electronic conductivity and Li-ion diffusion. By means of ex-situ XRD studies a two-step storage mechanism is proven. © 2021, The Author(s).This work was supported by the Deutsche Forschungsgemeinschaft through projects KL1824/12-1 and KL 1824/14-1. G.Z. acknowledges support of the state order via the Ministry of Science and Higher Education of Russia (No AAAA-A19-119031890025-9). E.T. acknowledges support by the BMWi through project 03ET6095C (HiKoMat). The authors thank I. Glass for experimental support

Structure of isophthalic acid based monolayers and its relation to the initial stages of growth of metal organic coordination layers

Self-assembled monolayers (SAMs) of isophthalic acid (IPA) and trimesic acid (TMA) formed on Cu modified Au(111) substrates by adsorption from aqueous solution were characterised by synchrotron-based X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and scanning tunneling microscopy (STM). Applying the layer-by-layer (LbL) method, the initial stages of growth of metal-organic coordination layers from Cu-acetate and TMA has been studied by STM. Both IPA and TMA SAMs exhibit a row structure with the aromatic units tilted by about 45 degrees with respect to the surface normal. The average distance between rows is 3 x Au-Au distance (=8.67 angstrom) with, however, slight variations between different rows. For IPA a very regular pattern is observed giving rise to a rectangular (9 x root 3) unit cell containing three molecules. Combining all data a structure is suggested where the molecules are tilted and azimuthally rotated. The variation in the inter-row distance is explained by correlated tilts and rotations in opposite directions. STM studies of the first two LbL deposition cycles reveal predominantly disordered nucleation at domain boundaries. The observation of epitaxial features is explained to arise from a particular combination of molecular orientation in adjacent rows.</p

Imaging of patterned self-assembled monolayers by scanning photoelectron microscopy

We have applied soft X-ray scanning photoelectron microscopy (SPEM) to image and characterize molecular pattems produced by electron irradiation of various aliphatic and aromatic thiol-derived self-assembled monolayers (SAMs) through masks. The fabricated patterns can be clearly distinguished and the inverse contrasts for the Au 4f and $C$ 1s images suggest that the goal of “chemical" imaging bas been achieved. The thickness of the films in the irradiated areas appeared to be higher than that in the non-irradiated ones. This can be explained by the adsorption of airborne carbon-containing molecules on the irradiated areas. In addition, the N 1s images were acquired from the structured films of NO$_2$(C$_6$H$_4$)$_2$SH on gold to monitor the electron irradiation-induced transformation of the nitro tailgroups into amino moieties. However, no chemical contrast related to the nitro-amino transformation was observed. This can be explained by the small intensity of the nitrogen photoelectron emission with respect to the inelastic background originated from the substrate and by the X-ray induced modification of the lithographie pattern during the image acquisition. The modification of aromatic SAMs caused by the zone-plate-focused X-ray beam has been utilized for direct lithographic writing by the microprobe

Employing X ray Photoelectron Spectroscopy for Determining Layer Homogeneity in Mixed Polar Self Assembled Monolayers

Self-assembled monolayers (SAMs) containing embedded dipolar groups offer the particular advantage of changing the electronic properties of a surface without affecting the SAM–ambient interface. Here we show that such systems can also be used for continuously tuning metal work functions by growing mixed monolayers consisting of molecules with different orientations of the embedded dipolar groups. To avoid injection hot-spots when using the SAM-modified electrodes in devices, a homogeneous mixing of the two components is crucial. We show that a combination of high-resolution X-ray photoelectron spectroscopy with state-of-the-art simulations is an ideal tool for probing the electrostatic homogeneity of the layers and thus for determining phase separation processes in polar adsorbate assemblies down to inhomogeneities at the molecular level