NIST creates spray-on transistors

The National Institute of Standards and Technology (NIST) is using organic semiconductors as a basis for spray-on large-area electronics such as solar cells and displays.

“At this stage, there is no established best material or manufacturing process for creating low-cost, large-area electronics,” says Calvin Chan, an electrical engineer at NIST. “What our team has done is to translate a classic material deposition method, spray painting, to a way of manufacturing cheap electronic devices.”

The team’s work showed that a commonly used organic transistor material, poly(3-hexylthiophene), or P3HT, works well as a spray-on transistor material.

When sprayed onto a flat surface, the P3HT film has a rough and uneven top surface – something that often causes problems in other applications. But because the transistor effects occur along its lower surface — where it contacts the substrate — it functions pretty well, says Chan.

Chan says the simplicity of spray-on electronics gives it a potential cost advantage over other manufacturing processes for organic electronics. Other methods, he says, require expensive equipment to function or are simply not suitable for use in high-volume manufacturing.

The new technique, by contrast, could lead to devices cheap enough to be disposable.