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The electrochemical deposition of ZnO thin fihns (2D layers) and nanowires on glass substrates covered with transparent conductive oxide (TCO) was studied with the purpose to use them in nanostructured solar cells. It was shown that the bath temperature and the electrolyte concentration played an important role on the ZnO layer morphology, composition, crystallization and optical properties. It was found that the thin films deposited from electrolytes with lower potassium chloride (KCl) concentration (0.1 M) and at temperatures higher than 50°C exhibit very good optical and structural properties. The rapid thermal annealing step at 500°C improves the ZnO film properties whereas the conventional annealing did not bring a real improvement. These 2D layers could be used subsequently for the electrodeposition ofZnO nanowires which dimensions could be tailored by the seed layer (2D layer) morphology and thickness. The supporting electrolyte (KCl) concentration and the passed charge density during the electrodeposition process could be additionally used to control their dimensions. Thus grown ZnO nanowires exhibit interesting optical and structural properties and therefore could be further integrated in nanostructured extremely thin absorber (eta) and hybrid (dye sensitized or polymer) solar cells. [ABSTRACT FROM AUTHOR]

This paper describes the formation of Cu nanofllms on a Ru/Ta-coated wafer using electrochemical atomic layer deposition (E-ALD). The initial steps involved cleaning and oxide removal from the Ru/Ta substrate using ultrahigh vacuum electrochemical system. Auger spectroscopy was used to follow the relative amounts of oxygen, Ru, and Cu on the wafer: as-received, after electrochemical treatment, after ion bombardment, and after Cu deposition. An automated flow cell electrodeposition system was employed to grow Cu nanofllms with up to 200 cycles using surface limited redox replacement (SLRR) reaction. The open-circuit potential was used to follow the exchange of Pb for Cu in the SLRR reaction. Electron probe microanalysis was used to determine the homogeneity of the Cu films. The use of a complexing agent (citrate) greatly improved the homogeneity. Different concentrations of citrate were investigated, containing 2 or 4 mM citrate. Atomic force microscopy images of the Cu films showed the ingress morphology to be the same as the egress when 4mM citrate was used. A prominent Cu(1ll) peak was displayed in the X-ray diffraction pattern for 200 cycles of Cu grown on the Ru/Ta-coated wafer. [ABSTRACT FROM AUTHOR]

Clarifying the nature of interactions between metal electrodes and organic molecules still represent one of the challenging problems in molecular electronics that needs to be solved in order to optimize electron transport through a molecular device. For this purpose, electronic properties at metal–molecule interfaces were studied by combining experimental and theoretical methods. Applying a novel electrochemical approach, strictly two-dimensional Pd islands were prepared on top of 4-mercaptopyridine self-assembled monolayers (4MP-SAMs) which, in turn, were deposited on (111)-oriented Au single crystals. Electron spectroscopy together with density functional theory calculations revealed strong interactions between the molecules and the islands due to Pd–N bonds, resulting in a drastically reduced density of states (DOS) at the Fermi level EF for a nearly closed Pd monolayer, and even non-metallic properties for nanometre-sized islands. Similarly, a significantly reduced DOS at EF was observed for the topmost Au layer at the Au–SAM interface due to Au–S interactions, suggesting that these effects are rather general. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we report on details of a new technique for depositing metal on top of a self-assembled monolayer (SAM). The experiments were performed with 4,4′-dithiodipyridine (4-PySSPy) SAMs on Au(111) electrodes, which were immersed without potential control into a Pd(II)-containing solution, where Pd(II) adsorbs on the surface by forming a complex with the pyridine nitrogen. The complexed Pd(II) ions were reduced electrochemically to Pd(0) after transferring the electrode to a Pd ion-free solution. Upon reduction, monoatomic high Pd islands were observed in STM. From cyclic voltammetry, in situ STM and ex situ angle-resolved XPS we conclude that these islands reside on top of the SAM, not underneath. It is shown that palladium complexation and deposition on self-assembled monolayers of 2-mercaptopyridine is not possible. [Copyright &y& Elsevier]

We report on the photosensitization of electrodeposited ZnO nanowire arrays with CuInS2 (CIS) extremely thin layers prepared by two methods: successive ionic layer adsorption and reaction (SILAR) and electrochemical deposition (ECD). This is the first time that such core (ZnO)/shell (CIS) nanostructures are realized. Using SILAR method, 20 nm thick films composed of CIS nanoparticles are grown after 15 deposition cycles. The final layer thickness when prepared by SILAR technique depends on the number of deposition cycles and is used as a main parameter to control it. For the electrodeposited CIS films the passed charge density during deposition is used for monitoring the film thickness. These room-temperature solution based methods (SILAR and ECD) appear to be very suitable for preparing good quality, thin uniform (in nanometer scale) films of absorbing materials. [ABSTRACT FROM AUTHOR]

Abstract: After the first report describing copper thiocyanate (CuSCN) nanowires (NWs) electrochemical deposition from an aqueous electrolyte at room temperature [1], the present study provides additional information on the effect of complexing agent and pH on their formation. The CuSCN electrodeposition from an aqueous solution is a two-step reaction, where in the first step Cu2+ is reduced to Cu+, and in the second step Cu+ chemically precipitates with SCN− to form CuSCN. In this study, CuSCN NWs are electrodeposited either potentiostatically or galvanostatically on flexible polyethylene terephthalate (PET) substrates covered with a transparent conductive oxide. It is shown that the nature of the Cu2+ chelating agent (diamino-tetraacetic acid compounds) and the pH value (between 1 and 2) of the electrolyte are the main parameters responsible for the CuSCN nanowire formation. The concentration limits of the Cu2+ chelating agent, Cu2+ and SCN− ions in the electrolyte are established to precise the region where CuSCN NWs could be grown. The CuSCN nanowire diameter and density could be tailored by the applied potential and SCN− concentration in the electrolyte. The possibility to deposit at room temperature CuSCN of good crystalline quality on flexible substrates is very promising and could further contribute to the decrease of the optoelectronic and photovoltaic device cost. [Copyright &y& Elsevier]