Biodegradable Electronics

A general goal in the development of any electronic component is to achieve high-performance operation and mechanical robustness which undergo negligible change over time. Recent advancements in materials science, thin film processing, and nanotechnology have, however, prospected the possibility of devices which can bend and stretch and provide the desired performance for a prescribed timeframe and, then, dissolve, resorb, or physically disintegrate upon the end of their functional time. Degradable or “transient” forms of electronics that disappear via hydrolysis or biochemical reactions, disintegration, and depolymerization could instill intelligence into resorbable implants, “green” environmental sensors, and biodegradable food packaging and lead to new compostable consumer electronic devices or printed boards so as to alleviate the problem of the electronic waste. Research has been driven by questions such as the following: Can we realize soft electronic implants which deliver diagnostics or therapeutic functions and then safely resorb in the body avoiding any additional surgery intervention? Can we realize compliant environmental sensors which harmlessly decompose to eliminate the need for their retrieval? This chapter starts from reviewing the materials that have demonstrated degradable behavior in various aqueous solutions. The emphasis is on those that are key ingredients to realize active electronic devices and circuits: semiconductors, dielectrics, and conductors. Another important class of materials is the polymers which have been used mostly for encapsulation and substrates. The attention then moves to devices especially on sensors, field effect transistors, LEDs, batteries, and solar cells. The chapter also provides an insight into the dissolution mechanisms and offers some examples of the fabrication methods adopted so far to build the devices. Finally, it ends by listing some of the challenges faced by this technology.