H. Lee, K. Ma
Kennesaw State University,
Keywords: nanotechnology, nanomaterial, inkjet printed, flexible electronics, printed electronics
Summary:Printed electronics have shown tremendous growth in recent years, and the demand for faster, smaller, cheaper, and more efficient printed devices is ever increasing. Inkjet printing is a technology which has demonstrated the ability to fabricate electronic components in a rapid, additive manner which can be scaled to mass production in roll-to-roll processing to meet these needs. Applications include displays, disposable electronics applications such as RFID tags, antennas, chemical sensors, biosensors, inductors, capacitors, and transistors. Chemical gas sensors have been designed and developed by integrating nanotechnology, wireless communication, and inkjet printing fabrication. Carbon nanotubes (CNT) are the nanomaterial have been inkjet-printed onto a printed antenna, all on a flexible organic substrate. The CNTs have been functionalized with poly-aminobenzene sulfonic acid (PABS), so that they are highly sensitive to ammonia gas. The ammonia molecules adhere onto the functionalized CNT, which changes the impedance. This change in impedance shifts the frequency of the antenna that the CNT has been printed onto, thereby indicating the presence of ammonia gas. These sensors can be used in applications such as detecting gas leaks as well as detecting improvised explosive devices (IEDs). The prospects of printed electronics is very high in the healthcare industry, where flexible wireless biosensors can be fabricated for point-of-care wireless health monitoring. Typically antennas lose significant gain when placed on the human body due to the conductivity of the body. These challenges have been met by the use of electromagnetic bandgap (EBG) antennas that are inkjet-printed on an organic substrate and placed on the human body. The use of EBG antennas improves the gain by close to two-fold, when compared to its performance in free space. Military is another promising field for printed electronics. The main challenge is the assembly of antennas for communication for soldiers on foot. Having wearable antennas that are flexible, light, with high efficiency and gain is a major issue that can be solved with the use of printed electronics. For a fully inkjet printed system, both passives such as inductors, capacitors, and resistors, as well as actives such as transistors is necessary. It has been demonstrated that magnetic iron and cobalt nanomaterial has been printed with inductors to increase the inductance. Dielectrics have also been printed with capacitors to increase the capacitance. Even transistors are now printed to enable a fully functional wireless circuit, that is entirely inkjet printed on paper or plastic or other flexible substrates. This poster shows the devices that have been printed for wireless sensors, wearable antennas, printed inductors, capacitors, transistors. Due to the extreme low-cost of fabrication, low profile, light weight, and flexibility, printed electronics can meet the demands in many different fields, including healthcare, military, sensing, and communication.