Manufacturing of bio-compatible & degradable devices using inkjet technology for transient electronics

The inkjet technology due to its gm-scale accuracy, up-scalability, efficient processing and industrial relevance, is widely accepted as a smart digital tool for manufacturing g-electronic devices on rigid and flexible substrates. Within this research, the inkjet technology is implemented to manufacture bio-compatible and bio-degradable conductive electrodes, contacts for electrical signal transmission/stimulation and development of the multilayered devices e.g. capacitors and thin-film-transistors (TFTs) along with suitable barrier layer characteristics, for implants in the medical applications. To accomplish such competitive goals, it is essential to select the most optimal functional materials, which would firstly fulfill the electrical needs of the device and secondly support processibility using the inkjet technology. The functional materials such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), natural semiconductors and shellac are here utilized in form, of commercially available and self-formulated inks, that are addressed carefully to deposit fundamental layers for printing capacitors and TFTs. The focus of this work is to decide on solution-processable device architectures e.g. BGBC TFTs, followed by the development and optimization of the deposition parameters for the specific materials tuned to defined layer thicknesses and concentrations. This supports in acquiring the desired electrical characteristics of conductivity, capacitance, charge transportation etc, and thus the device performance. The results show that the manufactured devices are achieved successfully on the bio-degradable substrates, processed entirely under 60 degrees C and ambient conditions. The electrical characteristics of the devices show direct dependency to the physical dimensions of the printed features, by exhibiting certain performance merits i.e. 210 +/- 50 pF/mm(2) and 10 mu A channel current.