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 ~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.

Flexible electronics fabricated on thin-film, lightweight, and bendable substrates (e.g., plastic) have great potential for novel applications in consumer electronics such as flexible displays, e-paper, and smart labels; however, the key elements, namely thin-film transistors (TFTs), for implementing flexible circuits often suffer from electrical instability. Therefore, thorough reliability analysis is critical for flexible circuit design to ensure that the circuit will operate reliably throughout its lifetime. In this article we propose a methodology for reliability simulation of hydrogenated amorphous silicon (a-Si:H) TFT circuits. We show that: (1) the threshold voltage ( V TH ) shift of a single TFT can be estimated by analyzing its operating conditions; and (2) the circuit lifetime can be predicted accordingly by using SPICE-like simulators with proper modeling. We also propose an algorithm to reduce the simulation time by orders of magnitude, with good prediction accuracy. To validate our analytical model and simulation methodology, we compare simulation results with the actual circuit measurements of an integrated a-Si:H TFT scan driver fabricated on a glass substrate and we demonstrate very good consistency.

Flexible electronics fabricated with thin-film and bendable substrates (e.g., plastic) have great potential for novel applications in consumer electronics such as flexible displays, e-paper, and smart labels; however, the key elements --- namely thin-film transistors (TFTs) --- often suffer from electrical instability. Therefore, thorough reliability analysis is critical for flexible circuit design to ensure that the circuit would operate reliably throughout its lifetime. In this paper, we propose a methodology for a-Si:H TFT circuits' reliability simulation. We show that: (1) the threshold voltage (VTH) shift of a single TFT can be modeled by analyzing its operating conditions and (2) the circuit lifetime can be predicted accordingly using SPICE. We also propose an algorithm to reduce the simulation time by orders of magnitude with negligible accuracy loss. To validate our analytical model and simulation methodology, we compare the SPICE simulation results with the actual measurements of our integrated a-Si:H TFT scan driver fabricated on the glass substrate and demonstrate very high consistency in the overall results.