LeRoy Apker Award Talk: Laser Printed Flexible Electronics

Organic electronics are at the forefront of the industry for large-area, low-cost flexible electronic applications, and provide an opportunity to incorporate electronics in non-traditional areas such as clothing, electronic paper, bio-integrated applications, and more. While several organic semiconductors have shown excellent electrical properties in single crystal form, reproducing these characteristics using low-complexity manufacturing processes has proven challenging. It is clear that the need to improve the performance of organic semiconductors while preserving their ease of manufacturing is critical for transitioning these devices from the laboratory to industry. To confront this challenge, in this work we explored two alternative methods for device fabrication that offer low-cost processability, compatibility with flexible substrates, and yield good device performance. The first method uses a laser printer for electrophotographic deposition of the organic semiconductor layer. We developed the first electronic device in which the semiconducting layer was laser printed. We performed electrical and structural characterization on the obtained thin-film transistors to relate the performance with the film microstructure and the quality of the semiconductor/dielectric interface. The second method, Graphite Aerosol Spray Lithography, employs laser printing for contact definition and uses a graphite aerosol to spray the electrodes. We show that this method can create contacts without using thermal or electron beam deposition, two common, expensive techniques. Furthermore, it replaces the complex lithography processes with a low-cost alternative based on printer toner. These methods offer insight into environmentally friendly and cost-effective processing for organic devices with an established technology such as the laser printer. This represents a step forward in developing scalable and cost-effective device fabrication techniques.