Building Electronics from Solution: Materials, Device Integration and Application Development

PARC is developing processes for printed and flexible electronics by integrating inorganic and organic materials with flexible substrates.  Solution-processed electronic materials have the potential to create a new manufacturing paradigm where consumer markets emerge in applications domains that are not currently 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, several solution-processed semiconducting materials were studied and applied to display applications. The recent development of metals and metal oxide nanoparticles and/or nanowires enables the fabrication of electronic devices that are fully built from solution.

I will discuss the development of a flexible 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 inkjet-printed organic semiconductors and integrated with pressure, acoustic, acceleration and temperature sensors based on piezoelectric polymers such as PVDF or PVDF-TrFE copolymer. Piezo electric polymers were chosen due to low-power requirements, low drift and relatively simple fabrication.  Polymer/polymer and polymer/small molecules blends are used in the fabrication of light sensors. PVDF and polymer semiconductors were integrated in the fabrication of non-volatile analog memory arrays. The device characteristics were monitored to understand the limiting factors to data retention time.

In this talk I will focus on the main challenges of flexible printed electronics: materials performance, TFT voltage operation, and printing as a manufacturing technology.