A new solvent can dissolve semiconductors safely and at room temperature.
Once dissolved, the semiconductor solution can be applied as a thin film to substrates like glass and silicon. Once heated, the solvent evaporates, leaving behind only a high-quality film of crystalline semiconductor—perfect for use in electronics.
“It’s inexpensive and easily scalable,” says Richard Brutchey, a chemistry professor at the University of Southern California (USC). “Our chemical understanding of the solvent system and how it works should allow us to expand it to the dissolution of a wide range of materials.”
While the technology already exists to “print” electronics using semiconductor “inks” at room temperature, the problem, until now, is that the only substance that could effectively dissolve semiconductors to form these inks was hydrazine—a highly toxic, explosive liquid used in rocket fuel.
Brutchey and David Webber of USC mixed two compounds to create the new solvent that effectively dissolves a class of semiconductors known as chalcogenides.
“When the two compounds work together, they do something quite remarkable,” says Brutchey.
They call the solvent an “alkahest,” after a hypothetical universal solvent that alchemists attempted to create to dissolve any and all substances. They’ve patented their alkahest, and recently presented their findings in the Journal of the American Chemical Society.
In the paper, they show how a mixture of 1,2-ethanedithiol (a colorless liquid that smells like rotten cabbage) and 1,2-ethylenediamine (a colorless liquid that smells like ammonia) is able to effectively dissolve a series of nine semiconductors made from combinations of arsenic, antimony, bismuth, sulfur, selenium and tellurium. Such semiconductors are often used in lasers, optics, and infrared detectors.
The National Science Foundation and USC funded the work.