Roll Printed Electronics: Development and Scaling of Gravure Printing Techniques

To realize the potential cost savings promised by printed electronics, high-speed, large-volume manufacturing methods must be established. Rotary printing techniques such as those used in the graphic arts are ideal candidates. However, very little research has been done on utilizing these techniques for printed electronics because digital processes such ink-jet printing have offered researchers a low-cost flexible solution for demonstrating the printability of their materials, despite the fact that these processes may be difficult to scale for large-volume manufacturing. In this thesis, gravure, a printing process which offers the highest resolution, highest speed, and largest volume production in the graphic arts is demonstrated as a viable technique for printed electronics. In order to make laboratory-scale research with this technique possible, a custom table-top gravure printing press was designed. This press allows for small amounts of ink to be utilized during a print and enables multi-layer prints with a registration accuracy not seen in conventional gravure printing presses and suitable for printed electronics. With this press, printing processes to deposit functional materials for printed circuits are investigated with a focus on developing process modules to manufacture fully printed organic thin film transistors. Considerable effort is made to establish processes to deposit metallic lines with feature sizes below 20 μm and a total surface roughness below 20 nm, uniform thin films of polymer dielectrics with thicknesses as low as 70 nm, and high performance polymer semiconductors. These processes are then integrated to manufacture capacitors suitable for integrated circuit components and organic thin film transistors with operating frequencies as high as 18 kHz

Roll Printed Electronics: Development and Scaling of Gravure Printing Techniques

To realize the potential cost savings promised by printed electronics, high-speed, large-volume manufacturing methods must be established. Rotary printing techniques such as those used in the graphic arts are ideal candidates. However, very little research has been done on utilizing these techniques for printed electronics because digital processes such ink-jet printing have offered researchers a low-cost flexible solution for demonstrating the printability of their materials, despite the fact that these processes may be difficult to scale for large-volume manufacturing. In this thesis, gravure, a printing process which offers the highest resolution, highest speed, and largest volume production in the graphic arts is demonstrated as a viable technique for printed electronics. In order to make laboratory-scale research with this technique possible, a custom table-top gravure printing press was designed. This press allows for small amounts of ink to be utilized during a print and enables multi-layer prints with a registration accuracy not seen in conventional gravure printing presses and suitable for printed electronics. With this press, printing processes to deposit functional materials for printed circuits are investigated with a focus on developing process modules to manufacture fully printed organic thin film transistors. Considerable effort is made to establish processes to deposit metallic lines with feature sizes below 20 μm and a total surface roughness below 20 nm, uniform thin films of polymer dielectrics with thicknesses as low as 70 nm, and high performance polymer semiconductors. These processes are then integrated to manufacture capacitors suitable for integrated circuit components and organic thin film transistors with operating frequencies as high as 18 kHz

Fully gravure and ink-jet printed high speed pBTTT organic thin film transistors

Organic thin film transistors with channel lengths below 20 mu m have been fabricated on plastic substrates using a combination of rotogravure and ink-jet printing exclusively. Gravure is utilized to deposit thin, smooth, and narrow metal lines ideal for gate electrodes; a poly(4-vinylphenol) dielectric; and a poly(2,5-bis(3-tetradecylthiophene-2-yl) thieno[3,2-b]thiophene) (pBTTT) semiconductor using a heated roll. A novel fluid guiding technique is used to maintain closely spaced ink-jet printed source and drain (S/D) contacts. Together these printing processes yield aggressively scaled yet easily manufacturable TFTs with operating frequencies of 18 kHz. (C) 2010 Elsevier B. V. All rights reserved.N

High-Speed Printing of Transistors: From Inks to Devices

The realization of a high-speed printing technique with high resolution and pattern fidelity is critical to making printed electronics a viable technology for electronics manufacturing. The printing requirements of printed electronics are substantially different that those of graphic arts. To make printed electronics a reality, it is necessary to deliver high resolution, good reproducibility, excellent pattern fidelity, high process throughput, and compatibility with the requisite semiconductor, dielectric, and conductor inks. In this paper, we review the physics of pattern formation from pixelated primitives, such as those that exist during inkjet and gravure printing, and will show how control of drop merging and drying can be used to produce high-fidelity shapes, including lines, squares, and intersections. We additionally discuss the physical underpinnings of gravure printing and inkjet printing, and show how these techniques can be scaled to produce high-fidelity highly scaled patterns, including sub-2 micron features at printing speeds of similar to 1 m/s. Finally, in conjunction with high-performance materials, we describe our realization of high-performance fully printed transistors on plastic, offering high-switching speed, excellent process throughput, and good fidelity over large areas.Y

Printed Transistors on Paper: Towards Smart Consumer Product Packaging

The integration of fully printed transistors on low cost paper substrates compatible with roll-to-roll processes is demonstrated here. Printed electronics promises to enable a range of technologies on paper including printed sensors, RF tags, and displays. However, progress has been slow due to the paper roughness and ink absorption. This is solved here by employing gravure printing to print local smoothing pads that also act as an absorption barrier. This innovative local smoothing process retains desirable paper properties such as foldability, breathability, and biodegradability outside of electronically active areas. Atomic force microscopy measurements show significant improvements in roughness. The polymer ink and printing parameters are optimized to minimize ink absorption and printing artifacts when printing the smoothing layer. Organic thin film transistors (OTFT) are fabricated on top of this locally smoothed paper. OTFTs exhibit performance on par with previously reported printed transistors on plastic utilizing the same materials system (pBTTT semiconductor, poly-4-vinylphenol dielectric). OTFTs deliver saturation mobility approaching 0.1 cm(2) V-1 s(-1) and on-off-ratio of 3.2 x 10(4). This attests to the quality of the local smoothing, and points to a promising path for realizing electronics on paper.N

MHz-Range Fully Printed High-Performance Thin-Film Transistors by Using High-Resolution Gravure-Printed Lines

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Supporting Data: Complementary Organic Logic Gates on Plastic Formed by Self-Aligned Transistors with Gravure and Inkjet Printed Dielectric and Semiconductors

The file contains the supporting data for the publication: S.G. Higgins, B.V.O. Muir, G. Dell'Erba, A. Perinot, M. Caironi, A.J. Campbell. Complementary Organic Logic Gates on Plastic Formed by Self-Aligned Transistors with Gravure and Inkjet Printed Dielectric and Semiconductors. doi: 10.1002/aelm.201500272. Advanced Electronic Materials (2015) See 'README.txt' for a description of the contents of the compressed file.The file contains the supporting data for the publication: S.G. Higgins, B.V.O. Muir, G. Dell'Erba, A. Perinot, M. Caironi, A.J. Campbell. Complementary Organic Logic Gates on Plastic Formed by Self-Aligned Transistors with Gravure and Inkjet Printed Dielectric and Semiconductors. doi: 10.1002/aelm.201500272. Advanced Electronic Materials (2015) See 'README.txt' for a description of the contents of the compressed file