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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Metal nanoparticles are known to form highly conductive films upon heating below 200 °C. We study the mechanism and morphological changes that occur as 3 nm, thiolate encapsulated, silver nanoparticles are annealed to form conductive films. We use X-ray diffraction (XRD), grazing incidence X-ray scattering (GIXS), and transmission electron microscopy (TEM) to monitor structural changes in the film. We show that the surfactant is present during the entire sintering process, that its presence greatly influences the grain size and crystallite orientation of the resulting film, and that the film becomes fully conductive in the presence of the surfactant. We show that particles that aggregate more rapidly form films that consist of smaller crystallites and are less textured. We further show that digestive ripening can lead to the degeneration of films back into particles, particularly when annealing in air versus an inert environment. Coalescence contributes to crystallite growth when particles are small but can confound both crystallite size and orientation development in the later stages of growth. The interaction of the surfactant with the particle is weakened by moisture, lowering the temperature at which the surfactant disassociates from the particle and sintering begins. Moisture also increases the rate of both aggregation and digestion, drastically changing the morphology of the films at any given temperature.

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Low-resistance printed 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. Furthermore, conductors of appropriate workfunction are also required to enable fabrication of printed Schottky diodes, necessary for rectification in RFID circuits. Last year, we demonstrated the formation of low-resistance conductive printed structures using gold nanoparticles. Here we demonstrate, for the first time, technologies for formation of printed conductors using silver and copper nanoparticles. These are particularly advantageous for several reasons. First, both silver and copper offer a 2X reduction in sheet resistance over gold, resulting in improved interconnect performance and inductor Q. Second, the material costs associated with both silver and copper are expected to be significantly cheaper than gold. Third, the workfunction of silver enables the fabrication of all-printed Schottky diodes with a silver rectifying contact to many common printable organic semiconductors.Solutions of organic-encapsulated silver and copper nanoparticles may be printed and subsequently annealed to form low-resistance conductor patterns. We describe novel processes for forming silver and copper nanoparticles, and discuss the optimization of the printing/annealing processes to demonstrate plastic-compatible low-resistance conductors. By optimizing both the size of the nanoparticle and the encapsulant sublimation kinetics, it is possible to produce particles that anneal at low-temperatures (<150 °C) to form continuous films having low resistivity and appropriate workfunction for formation of rectifying contacts. This represents a major component required for allprinted RFID. INDRODUCTIONIn recent years, there has been tremendous interest in flexible electronics. Besides the obvious applications of flexible electronics in flat panel displays [1], flexible circuits are also promising for use in such applications as radio frequency identification (RFID) tags [2], low cost sensors [3], and other disposable electronic devices. In particular, devices based on organic semiconductors are considered to be very promising for these applications since they may potentially be fabricated entirely using printing technologies [4], eliminating the need for such major cost points as lithography, vacuum processing including physical vapor deposition, plasma etching, and chemical vapor deposition, while simultaneously allowing the use of reel-to-reel processing, resulting in reduced substrate handling and clean room costs as well. Furthermore, since printing is inherently additive in nature, material and disposal costs are also expected to be reduced, resulting in an extremely low net system cost.