Prof. Ana Claudia Arias
Electrical Engineering and Computer Science Department
University of California in Berkeley
Solution-processed electronic materials have the potential to create a new manufacturing paradigm and applications domains beyond those now dominated by silicon technology. These materials can be deposited and patterned with tools commonly used in the graphics design and printing businesses. Over the past 10 years, solution-processed semiconducting materials have been studied largely for incremental application in information display. However, combining derivatives of these semiconductors with emerging solution-dispersible metal and metal oxide nanoparticles and nanowires enables the fabrication of electronic devices that are fully built from solution. This establishes a new device processing platform which, in turn allows device form factors and integration of functionality in systems not feasible in any conventional semiconductor technology. Examples of novel applications and systems enabled by this include: large-area, ultralight and flexible power harvesting, logic-integrated sensing and memory technologies. In this talk, I will discuss the development of a flexible integrated blast dosimeter to illustrate and demonstrate the challenges and advantages of using solution-processed electronic materials for flexible and disposable applications. The blast dosimeter tapes developed at PARC are used to detect the occurrence of events that cause traumatic brain injury (TBI). TBI is a medical condition that is cumulative and triggered by events such as blast pressure waves, noise, acceleration and extremely bright light. The sensor tape has integrated sensors, signal conditioning electronics, non-volatile memory and a thin film battery. The electronic circuits are based on digitally-printed organic semiconductors and integrated with pressure, acoustic, acceleration and temperature sensors based on piezoelectric polymers such as PVDF or PVDF-TrFE. Piezoelectric polymers were chosen based on their ability to meet low-power, low drift and simple fabrication constraints. Active regions formed with distribute interface semiconductor networks based on polymer/polymer and polymer/small molecule systems were used in the fabrication of the printed light sensors. Polarizable solution-processed dielectrics and polymer semiconductors were integrated in the fabrication of non-volatile analog memory arrays. Memory device characteristics were monitored to understand the limiting factors to data retention time. Combined together, these elements demonstrate an integrated sensing, logic and memory system which begins to demonstrate the potential of this approach. In this talk I will also discuss the main challenges for flexible printed electronics: materials performance, TFT operation voltage, and printing as a manufacturing technology.
Ana Claudia Arias is an Associate Professor at the Electrical Engineering and Computer Science Department at the University of California in Berkeley. Prior to joining the University of California she was the Manager of the Printed Electronic Devices Area and a Member of Research Staff at PARC, a Xerox Company, Palo Alto, CA. At PARC she used inkjet printing techniques to fabricate organic active matrix display backplanes for paper-like displays and flexible sensors. She went to PARC from Plastic Logic in Cambridge, UK where she led the semiconductor group. She did her PhD on semiconducting polymer blends for photovoltaic devices at the University of Cambridge, UK. Prior to that, she received her master and bachelor degrees in Physics from the Federal University of Paraná in Curitiba, Brazil. Her research work in Brazil focused on the use of semiconducting polymers for light emitting diodes. Ana Claudia is a member of the board of directors of the Materials Research Society (MRS) and a member of the technical advisory board of ThinFilm Electronics and Linde Nanomaterials.