We have studied inkjet-printed drops of a conductive polymer. We show how varying drop spacing and temperature lead to several different printed line morphologies and offer a simple geometric explanation for these various forms. Also, by controlling the evaporation profile of drying drops and lines, we demonstrate control of the coffee ring effect by which solute is transferred to the rim. Under appropriate conditions, we are able to enhance or eliminate the coffee ring effect in our drying features.

The effect of varying the hydrothermal time to synthesize manganese oxide (MnO(2)) nanostructures was investigated along with their influence on structural, morphological, compositional, and electrochemical properties in supercapacitor electrode materials. XRD and TEM studies showed that the MnO(2) prepared in shorter hydrothermal dwell time was a mixture of amorphous and nanocrystalline particles, and there was an evolution of crystallinity of the nanostructures as the dwell time increased from 1 to 18 h. Interestingly, SEM, TEM, and HRTEM revealed a variety of structures ranging from nanostructured surface with a distinct platelike morphology to nanorods depending upon the hydrothermal reaction time employed during the preparation of the manganese oxide: increasing the amount of individual nanorods in the materials prepared with longer hydrothermal reaction time. The surface area of the synthesized nanomaterials varied from 100 to 150 m(2)/g. Electrochemical properties were evaluated using cyclic voltammetry (CV) and galvanostatic charge-discharge studies, and the capacitance values were in the range 72-168 F/g depending upon synthesis conditions. The formation mechanism of the nanorods and their impact on the specific capacitance were discussed in detail.

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As thin films become increasingly popular (for solar cells, LEDs, microelectronics, batteries), quantitative morphological and crystallographic information is needed to predict and optimize the film's electronic, optical and mechanical properties. This quantification can be obtained quickly and easily with X-ray diffraction using an area detector in two simple sample geometries. In this paper, we describe a methodology for constructing complete pole figures for thin films with fiber texture (isotropic in-plane orientation). We demonstrate this technique on semicrystalline polymer films, self-assembled nanoparticle semiconductor films, and randomlypacked metallic nanoparticle films. This method can be immediately implemented to help 2 understand the relationship between film processing and microstructure, enabling the development of better and less expensive electronic and optoelectronic devices.Keywords: grazing-incidence X-ray diffraction; pole figure; texture analysis; morphology; thin film IntroductionThe optical and electronic properties of polycrystalline and semicrystalline materials are highly dependent on the materials' morphology. When these properties are anisotropic in the single crystal form, the corresponding bulk properties of the poly-or semi-crystalline material are often dependent upon the orientation distribution of the crystallites.1 As efforts are made to optimize the electrical and optical properties of functional, solution-processed polycrystalline films used for thin film transistors, solar cells, and other emerging technologies, it is necessary to fully characterize the orientation distribution, or texture, of the crystallites. There has been much effort devoted to correlating the microstructure and properties of thin films (<100 nm) of nanostructured organic semiconductors 2-7 and inorganic semiconducting nanoparticles 8,9 , but the collection of complete texture information is often challenging due to the limited film thickness.In this work, we introduce an X-ray diffraction-based method for collecting and constructing quantitative pole figures with an area detector for thin films with isotropic crystallographic orientation in the substrate plane (classically referred to as fiber texture). The technique is rapid and ideal for thin films that are sensitive to beam damage, diffract weakly or are otherwise limited by their thin film form to certain diffraction geometries. 3A pole figure is a plot of the orientation distribution of a particular set of crystallographic lattice planes, providing a useful illustration of a material's texture. Traditional pole figures of bulk samples can be collected in either reflection or transmission mode. Pole figures collected in a reflection mode utilize a symmetric geometry introduced by Schultz 10-12 . In this technique, diffraction intensities are collected using a point detector as the sample is rotated along two axes.Accurate collection of intensity in the Schultz geometry is generally limited to within 85° of the surface normal, due to distortions t...

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Low resistance conductors are crucial for the development of ultra-low-cost electronic systems such as radio frequency identification tags. Low resistance conductors are required to enable the fabrication of high-Q inductors, capacitors, tuned circuits, and interconnects. The fabrication of these circuits by printing will enable a dramatic reduction in cost, through the elimination of lithography, vacuum processing, and the need for high-cost substrates. Solutions of organic-encapsulated gold nanoparticles many be printed and subsequently annealed to form low resistance conductor patterns. We describe a process to form the same, and discuss the optimization of the process to demonstrate plastic-compatible gold conductors for the first time. By optimizing both the size of the nanoparticle and the length of the alkanethiol encapsulant, it is possible to produce particles that anneal at low temperatures (Ͻ150°C) to form continuous gold films having low resistivity. We demonstrate the printing of these materials using an inkjet printer to demonstrate a plastic-compatible low resistance conductor technology.

Carbon materials were synthesized from banana fibers by treating the fibers with pore-forming substances such as ZnCl 2 and KOH with an intention to improve the surface area and their electrochemical performance as electrical double-layer capacitor electrodes. The performance of these materials was studied in a neutral electrolyte for the first time. There has been a substantive increase in the specific surface area of the treated carbon material because of the effective pore generations. The structural and surface properties of the prepared carbon materials were studied using scanning electron microscopy and N 2 adsorption/desorption studies. The surface area of the 10% ZnCl 2 treated sample was found to be 1097 m 2 /g. The electrochemical properties of untreated and porogen treated carbons were evaluated by using cyclic voltammetry and galvanostatic chargedischarge studies, and the specific capacitance as high as 74 F/g in 1 M Na 2 SO 4 neutral electrolyte was obtained for 10% ZnCl 2 treated carbon as determined by constant current charge-discharge studies. The system showed excellent cyclability with a Coulombic efficiency of ∼88% at a high current density of 500 mA/g for 500 cycles. The electrochemical performance of the high surface area carbon in the neutral electrolyte medium is significantly high, and the reasons are discussed.

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