A team from Tel Aviv University may have a solution; biodegradable transistors that are protein-based, essentially composed of organic materials found in...you.
Working with blood, milk, and mucus proteins which have the ability to self-assemble into a semi-conducting film, the researchers have already succeeded in taking the first step towards biodegradable display screens, and they aim to use this method to develop entire electronic devices. Technology is trying to shift from a silicon era to a carbon era and transistors built from these proteins will be ideal for smaller, flexible devices that are made out of plastic rather than silicon, which exists in wafer form that would shatter like glass if bent. It could lead to a new range of flexible technologies, such as screens, cell phones and tablets, biosensors, and microprocessor chips.
One of the challenges of using silicon as a semi-conductor is that a transistor must be created with a "top down" approach. Manufacturers start with a sheet of silicon and carve it into the shape that is needed, like carving a sculpture out of a rock. This method limits the capabilities of transistors when it comes to factors such as size and flexibility.
The TAU researchers turned to biology and chemistry for a different approach to building the ideal transistor. When they appled various combinations of blood, milk, and mucus proteins to any base material, the molecules self-assembled to create a semi-conducting film on a nano-scale. In the case of blood protein, for example, the film is approximately four nanometers high. The current technology in use now is 18 nanometers, says Mentovich.
Together, the three different kinds of proteins create a complete circuit with electronic and optical capabilities, each bringing something unique to the table. Blood protein has the ability to absorb oxygen, Mentovich says, which permits the "doping" of semi-conductors with specific chemicals in order to create specific technological properties. Milk proteins, known for their strength in difficult environments, form the fibers which are the building blocks of the transistors, while the mucosal proteins have the ability to keep red, green and, blue fluorescent dyes separate, together creating the white light emission that is necessary for advanced optics.
Overall, the natural abilities of each protein give the researchers "unique control" over the resulting organic transistor, allowing adjustments for conductivity, memory storage, and fluorescence among other characteristics.
Study in Nano Letters and Advanced Materials