The future direction of electronic devices is centered on flexibility. This is a key design requirement for wearables as well as for portable devices. To achieve this flexibility needs to extend to every aspect of the device.
This includes the semiconductor and this is what has been worked on at Stamford University. Researchers have created a new type of semiconductor that is described as being as flexible as skin. In addition it offers a green solution, in being easily degradable. This latter part means that the semiconductor will not adding to the burgeoning pile of global electronic waste. In the U.S. alone, around 3,140,000 tons of electronic waste is produced per year. Of this about 40 percent is recycled 40 and the remainder goes for landfill.
The inspiration for the semiconductor is human skin, according to lead researcher Professor Zhenan Bao. In her research note she states
: “In my group, we have been trying to mimic the function of human skin to think about how to develop future electronic devices”. The researcher created a stretchable electrode modeled on human skin, which will be the basis for many types of wearable electronic devices.
Explaining how things have developed, she adds: We have achieved the first two – flexible and self-healing – so the biodegradability was something we wanted to tackle.”
In tackling the issue of biodegradability, the researchers have created a semiconductor that can be dissolved by adding a few drops of acetic acid (the acid that makes up vinegar). This is based on semiconductors made from a special type of polymer.
To support the polymer the researchers have also come up with a degradable electronic circuit together with a new biodegradable substrate material. The substrate is designed for mounting the electrical components. This means an entire, flexible electronic device can be disposed of in an environmentally acceptable way through biodegradation into nontoxic components.
Developing these materials took considerable research. In the end the scientists came up with a special type of chemical linkage for the material; this is a linkage that can retain the ability for the electron to smoothly transport along the molecule.
As well as helping with waste disposal, biodegradable electronics can also be used inside the human body for medical applications and for monitoring remote areas on the planet where there is a concern of leaving redundant and polluting equipment around.
The semiconductor is described in the journal Proceedings of the National Academy of Sciences
. The research paper is titled “Biocompatible and totally disintegrable semiconducting polymer for ultrathin and ultralightweight transient electronics.”