Scientists in the United States have developed a non-toxic silicon ink which could lead to the production of durable, electrical devices at a dramatically reduced cost.
Researchers from the College of Science and Engineering at the University of Minnesota and the National Renewable Energy Laboratory in Golden, Colorado have teamed up to create an innovative technology for the production of “electronic ink” – a liquid comprised of nanometre-sized silicon crystals which can be used to “print” the working circuitry of electronic devices in the form of a film onto plastic sheets.
The team’s new method managed to solve a key problem in the production of electronic ink which has thus far hampered its widespread application – the necessity of soap-like molecules called ligands, which permit the production of ink with a long shelf life but which leave a residue on the films after printing which severely compromises their electrical quality.
The production method dispenses with the need for ligands by using a non-thermal plasma to cover the surface of the liquid with chlorine atoms, which in turn reacts with common solvents to permit the creation of stable silicon inks.
The use of solvents also further enhances the electrical properties of the ink by “doping” them – which refers essentially to the introduction of impurities in order to heighten conductivity.
The researchers discovered that the use of common solvents served to dope the silicon inks following printing and conferred them with a level of conductivity around 1,000 times greater than un-doped silicon nanoparticle films.
“What this research means is that we are one step closer to producing more pure and more stable electronic ink with non-toxic chemicals,” said Uwe Kortshagen, a professor in mechanical engineering at the University of Minnesota and a co-author of the paper.
A cheap, non-toxic electronic ink could revolutionize the production of hi-tech devices such as touch pads and solar cells by radically reducing the cost of producing them and making them affordable even for the poor and disadvantaged.
“Imagine a world where every child in a developing country could learn reading and math from a touch pad that costs less than $10 or home solar cells that finally cost less than fossil fuels,” Kortshagen said.
The researchers have published their findings in online research publication Nature Communications and have already obtained a provisional patent on the technology.