The authors present the feasibility of sheet fed direct gravure printing for ultrathin, organic semiconductor films on ITO coated glass. Printing with chrome plated gravure cylinders is often believed to require flexible substrates to promote fluid transfer to the substrate. However, the results demonstrate a stable process for the small-molecule Spiro-MeOTAD dissolved in toluene on rigid substrates. The authors obtained layer thicknesses in the range of 5–100 nm. They identified certain boundaries for gravure cell size yielding printed films with thickness of 10–15 nm with good homogeneity suitable for organic light emitting diodes or organic photovoltaics. For gravure cells smaller or larger than the optimal range, the printed layer is afflicted with dot- or ribbinglike structures. The authors show that the latter may result from nip-induced Saffman–Taylor instabilities rather than spinodal dewetting or Marangoni effects. Finally, electrical characterization of a completed stack (PEDOT:PSS electrode) give evidence for integrity of the printed semiconductor layers.

Due to its flexibility and ease of patterning, ink jet printing has become a popular technique for the noncontact deposition of liquids, solutions, and melts on a variety of substrates at lateral resolutions down to 10 μm. This article presents a study of ink jet printing of homogeneous layers of Orgacon™ (Agfa-Gevaert, Belgium), a water-based dispersion of poly(3,4-ethylenedioxythiophene):poly (styrenesulfonic acid) (PEDOT:PSS). The printed PEDOT:PSS layer can be used as a transparent electrode in organic light-emitting diodes (OLEDs). Fundamental aspects of the interaction between the ink jet ink and the substrate and the resulting homogeneity of the active layer in relation to OLED device performance are investigated. The optimized PEDOT:PSS ink formulation is shown to improve layer homogeneity, resulting in a uniform light output and device efficiency. Ink jet printing is shown to be capable of fabricating 25×25 mm OLED devices that have equivalent efficiency and light uniformity to the ones produced by spin coating.

This article reports on a number of experiments that have been performed, which show that the resistance of silver lines formed in channels is lower than silver lines that have been formed on unstructured surfaces. Channels were formed either by being cut into polyimide (Kapton) using a laser or by hot embossing a polycarbonate blend (Bayfol). An ink jet printer was used to dispense silver-containing ink over the embossed channels, the laser cut channels and over unstructured Kapton and Bayfol to allow comparison. Two types of silver-containing ink were used, one was a nanoparticle (NP) ink and the other was a metallo-organic decomposition (MOD) ink. For the NP ink, a decrease in resistance was seen for the lines formed in hot embossed channels. For the MOD ink, the resistance decrease was seen for lines formed in both the embossed and the laser cut channels.

In this study, a strategic analysis of the most successful printing techniques in terms of their capability to make high resolution patterns, i.e., the laser transfer and reverse offset printing techniques, is conducted and a novel self-differentiation technique is introduced on the basis of the modified strategy. The proposed self-differentiation technique is based on the high resolution subtractive patterning of a cheap material coated on a substrate and the subsequent low-resolution additive patterning of metallo-organic silver ink. The novelty of this self-differentiation technique lies in its capability to convert metallo-organic silver ink to either conductive or nonconductive patterns, as intended. With the proposed self-differentiation technique, conductive and nonconductive patterns were successfully self-differentiated, no matter where the metallo-organic silver ink was applied, and the line resistance of the self-patterned metal electrode, as fine as 190.1±0.3 μm in line width, was as low as 24.8±0.2 Ω/cm.

The interest in functional ceramic coatings based on low cost and flexible manufacturing has been heightened by the effectiveness shown by chemical solution deposition of metal-organic salts, usually based on the use of spin coating, dip coating, or slot die coating techniques prior to thermal treatment to achieve decomposition of the starting salts. The possibility of implementing effective drop on demand systems in the manufacturing process allows a more efficient way to apply the precursor solution homogeneously onto the substrate, thus, enabling control of thickness of the ceramic coating, by controlling the drop size and the pitch of the printing pattern, among other manufacturing advantages such as control of solvent evaporation. In the present work, the authors report on their experiments concerning ink jet coating of functional complex ceramics for La_0.7Sr_0.3Mn_O3 and YBa₂Cu_3O7–x layers and patterns over single crystal and polycrystalline substrates using an electromagnetic system and a single nozzle piezoelectric dispenser. Characterization of rheological properties of the developed ink and of the resulting coating by optical microscopy, x-ray diffraction, scanning electron microscopy, and magnetic behavior are reported.

The effects of nozzle defects on the behavior of drops ejected from drop-on-demand printheads were studied. Nozzles in two types of commercial printheads were modified with two different micromachining techniques: focused ion beam (FIB) milling and pulsed laser micromachining. Nozzles were modified by producing single or multiple notches on their edges. The studies focused on the volume, speed, and direction of travel of the drops. Fifteen different types of geometrical defects on nozzles were studied. Shadowgraph images were used to determine the drop size, speed, and trajectory from the same nozzles before and after modification. The results indicate that geometrical defects up to ∼100 μm² at the front (exit) face of a 50 μm diameter tapered nozzle do not cause any significant variation in the behavior of these nozzles, but that defects at the back (entry) of the nozzle can have a major effect on the direction of jetting.

At present, electrophotography has not drawn much attention as a digital manufacturing technique. But it has the potential to be an alternative to ink jet for some interesting applications. The authors introduce a novel and a highly efficient manufacturing process for biochips (peptide arrays) based on electrophotography. Peptide arrays are powerful tools for developing new medical agents for diagnosis and therapy techniques. They are predicted to become as important as DNA arrays provided it is possible to produce peptide arrays in sufficient complexity at moderate costs. After the major scientific goals of the manufacturing process were achieved, a step toward series production has now been made.

Characterization of total dot gain gives a good insight to the study of paper and print. In this article, we propose three approaches based on the Murray–Davies model to obtain total dot gain. In the first approach, the total gain is approximated by minimizing the root-mean-square between the calculated spectrum and the reflected spectrum measured by the spectrophotometer. The other two approaches are based on microscale images captured by a high resolution camera. These two approaches differ in their schemes on how to obtain the gray tone of the full-tone ink. By the use of microscale images, the authors also illustrate the shape of the effective dot area for the investigated paper substrate. They also study the histograms of the reflected and transmitted microscale images. This comparison shows that although the transmitted image has less optical dot gain compared to the reflected image, the transmittance also incorporates some small amount of optical dot gain.

As the dynamic range of a digital camera is narrower than that of a real scene, the captured image requires a tone curve or contrast correction to reproduce the information in dark regions. Yet, when using a global correction method, such as histogram-based methods and gamma correction, an unintended contrast enhancement in bright regions can result. Thus, a multiscale retinex algorithm using Gaussian filters was already proposed to enhance the local contrast of a captured image using the ratio between the intensities of an arbitrary pixel in the captured image and its surrounding pixels. The intensity of the surrounding pixels is estimated using Gaussian filters and weights for each filter, and to obtain better results, these Gaussian filters and weights are adjusted in relation to the captured image. Nonetheless, this adjustment is currently a subjective process, as no method has yet been developed for optimizing the Gaussian filters and weights according to the captured image. Therefore, this article proposes local contrast enhancement based on an adaptive multiscale retinex using a Gaussian filter set adapted to the input image. First, the weight of the largest Gaussian filter is determined using the local contrast ratio from the intensity distribution of the input image. The other Gaussian filters and weights for each Gaussian filter in the multiscale retinex are then determined using a visual contrast measure and the maximum color difference of the color patches in the Macbeth color checker. The visual contrast measure is obtained based on the product of the local standard deviation and locally averaged luminance of the image. Meanwhile, to evaluate the halo artifacts generated in large uniform regions that abut to form a high contrast edge, the artifacts are evaluated based on the maximum color difference between each color of the pixels in a patch in the Macbeth color and the averaged color in CIELAB standard color space. When considering the color difference for halo artifacts, the parameters for the Gaussian filters and weights representing a higher visual contrast measure are determined using test images. In addition, to reduce the induced graying-out, the chroma of the resulting image is compensated by preserving the chroma ratio of the input image based on the maximum chroma values of the sRGB color gamut in the lightness–chroma plane. In experiments, the proposed method is shown to improve the local contrast and saturation in a natural way.