Within the last year, the intensive development of π-conjugated small molecule acceptors has yielded viable alternatives to fullerene acceptors in state-of-the-art organic photovoltaic devices.

Thin film libraries of sputtered have been investigated for use as negative electrode materials in Li-ion rechargeable batteries. Results from over 200 compositions are reported here. The observed capacity decreases as transition metal content increases, approaching zero around 50 atom % Si, and can be approximated assuming active Si in an inactive SiM Fe, Mn or Ni) matrix. Plots of differential capacity vs. potential are characteristic of a-Si in an inert matrix, in agreement with X-ray diffraction results. The behavior of Si-Mn thin film libraries differs from that of Si-Fe and Si-Cr-Ni libraries for the range of 50 to 70 atom % Si. © 2005 The Electrochemical Society. All rights reserved.

Submonolayer coverages of the molecule 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) deposited on NaCl(001) surfaces were imaged with high resolution noncontact-atomic force microscopy. Two island types were observed: monolayer islands with a $p3\times 3$ epitaxy at low coverage and a mixture of these and bulklike crystallites at higher coverage. The transition between the pure monolayer islands and mixed islands occurs at $\sim 0.85\mathrm{ML}$, corresponding to a complete $p3\times 3$ layer. Calculations show the $p3\times 3$ epitaxy to be incompatible with a multilayer crystal of PTCDA. Consequently, the growth of additional layers results in an adaptation of the interface structure forcing a dewetting transition.

Design, testing, and performance of a 64-channel combinatorial electrochemical cell are described. This cell is used for high-throughput screening of materials for use as Li-ion rechargeable battery electrodes. Our sealed cell has 64 separate positive electrodes and Li foil for the reference and counter electrodes. This combinatorial electrochemical cell was designed to complement our existing combinatorial materials science infrastructure. Using the combinatorial electrochemical cell decreases the time and labor associated with test cell assembly, improves the repeatability of our assembly procedure, and increases the number of compositions we can test in a given amount of time. In this paper, we demonstrate that the results from the combinatorial electrochemical cell and from conventional 2325 coin-type test cells, containing electrodes of sputtered films prepared in the same sputtering run, are identical for electrodes of the same composition. © 2003 The Electrochemical Society. All rights reserved.

Amorphous alloys of Si and Sn exhibit large specific and volumetric capacities when cycled electrochemically vs. lithium. To improve the electrochemical performance of these materials, we explore here the effect of Al additions to the alloys. Combinatorial films of were prepared by magnetron sputtering and then analyzed for structure, composition, and electrochemical performance. If the film is amorphous, the voltage-capacity behavior of the cell is smooth and the differential capacity vs. potential shows no sharp peaks, indicating homogeneous insertion of lithium. If the film contains crystalline material, the voltage-capacity relation shows plateaus and peaks are seen in the differential capacity, indicating inhomogeneous insertion of lithium. If the film is amorphous, capacity retention is generally good, while films containing crystalline material have poor capacity retention. A summary of specific capacity and reversible capacity as a function of composition is presented. © 2003 The Electrochemical Society. All rights reserved.

Recent attention given to the growth and morphology of organic thin films with regard to organic electronics has led to the observation of dewetting (a transition from layer(s) to islands) of molecular deposits in many of these systems. Dewetting is a much studied phenomenon in the formation of polymer and liquid films, but its observation in thin films of the 'small' molecules typical of organic electronics requires additional consideration of the structure of the interface between the molecular film and the substrate. This review covers some key concepts related to dewetting and molecular film growth. In particular, the origins of different growth modes and the thickness dependent interactions which give rise to dewetting are discussed in terms of surface energies and the disjoining pressure. Characteristics of molecular systems which may lead to these conditions, including the formation of metastable interface structures and commensurate-incommensurate phase transitions, are also discussed. Brief descriptions of some experimental techniques which have been used to study molecular dewetting are given as well. Examples of molecule-on-insulator systems which undergo dewetting are described in some detail, specifically perylene derivatives on alkali halides, C(60) on alkali halides, and the technologically important system of pentacene on SiO(2). These examples point to some possible predicting factors for the occurrence of dewetting, most importantly the formation of an interface layer which differs from the bulk crystal structure.