Organic semiconductors will enable technologies like displays, detectors, and biomedical sensors that are light weight, flexible, and low-cost. Manufacturing electronic devices requires the ability to pattern different materials in separate layers to define the design space for a device. A significant obstacle for the development of organic electronic devices is the lack of a patterning technology with the disruptive power that photolithography exerted in traditional microelectronics. There is therefore a critical need to develop scalable and rapid photopatterning methods capable of producing organic semiconductor structures with sub-micrometer resolution. Just as the three-dimensional 3D printer is an enabling tool for low cost part fabrication, this Scalable NanoManufacturing (SNM) award will enable development of solution processing steps for the fabrication of nanoscale multi-layer organic electronic devices. This research involves collaboration between science, engineering, and industry partners in chemistry, materials, optical processing, and chemical process development. The fundamental knowledge needed for nanomanufacturing will be integrated into university curricula and transferred to undergraduate students through research internships. Graduate students will experience hands-on industry partnerships through collaboration with Palo Alto Research Center (PARC). The next generation of researchers, particularly minorities, will be engaged through involvement in 4-H projects in electronics.
Resolution on solution-printed organic electronics has been limited to 10's of µm due to the inherent limitations of solution printing or evaporation through a shadow mask. Photolithography has also been limited due to mutual solubility and miscibility of organic materials and material damage associated with photomask removal. In this research program we develop a new approach in which the solubility of the organic semiconductor itself is controlled by photo-reversible charge-transfer chemistry, enabling diffraction-limited patterning of organic electronic materials. This technical breakthrough enables the patterning of either the organic semiconductor or the doping level within the semiconductor using light exposure. The research team will explore chemical synthesis of new charge transfer dopants to enable the application of this technology to a broader array of semiconductors, optical processing to reduce write times and feature size, and chemical processing to make each sequential step consistent with high-throughput roll-to-roll processing, the ultimate focus of which is the development of all-organic transistor arrays with doped organic electrodes, patterned gates, and high switching speeds. The nanomanufacturing process will be scaled-up to large areas using student internships and equipment at PARC.
