MIT Scientists Make Functioning Printable Stamp Electronics

Scientists have made a new stamping technique that creates functional features at nano-scale dimensions. This means the world of printable electronics is just upon us.

The next time you place your coffee order, imagine placing a sticker on your cup that lets you know the precise temperature of your order. Perhaps a new stamping method can display a "countdown" that warns of spoiling produce, or even a window pane that shows the weather outside.

According to MIT, its engineers have invented a "fast" and precise printing process that may allow such electronic surfaces to be real and inexpensive. 

In their paper, the researchers report they have been able to fabricate a stamp made from forests of carbon nanotubes able to print electronic inks onto rigid and flexible surfaces.

John Hart from MIT said the team's stamping process should be able to print transistors small enough to control individual pixels in high-res displays and touchscreens.

This new technique may offer a relatively cheap and fast way to manufacture electronic surfaces for as-yet-unknown applications.

According to Digital Trends, there already have been other attempts to print electronic surfaces using inkjet printing and rubber stamping techniques with fuzzy results. This is because such techniques are difficult to control at very small scales and tend to produce "coffee ring" patterns where ink spills over borders or even uneven prints that can lead to incomplete circuits.

Hart and his team wanted to print electronics much more precisely by designing "nanoporous" stamps, to allow a solution of nanoparticles or "ink" to flow uniformly through the stamp and onto whatever surface is to be printed.

According to ZME Science, this allows stamps to have a much higher resolution than conventional rubber stamp printing, referred to as flexography.

To make the stamps, the researchers used the group's previously-developed techniques to grow carbon nanotubes on a surface of silicon in various patterns. They then coated them with a thin polymer layer to ensure the ink would penetrate throughout the nanotube forest and not shrink after the ink was stamped. 

The key is to find the precise amount of pressure needed to stamp the ink properly, which the team wants to solve by printing a machine that controls the force used to press the stamp against the substrate.

The next step, then, is to pursue the possibility of fully-printed electronics. This includes using materials such as graphene that would allow ultrathin electronic and energy-conversion devices.