For the first time, scientists have combined light sensors and polymer-based electronics to create a flexible sensor that lights up when touched. The more pressure put on the sensor, the brighter it gets.
It seems like a simple thing to do, but in fact it's hugely challenging to combine light sensors and electronics made of different crystalline materials onto the same foundation, or substrate. Crystalline materials have microscopic structures that work against each other when put down on the same surface.
The World's Tiniest 3-D Jigsaw Puzzle
But Ali Javey, an associate professor of computer sciences at the University of California at the University of California, Berkeley, and his colleagues found a way. They came up with two printing methods to attach nanowire circuitry and photosensors to a flexible surface, and the two solutions could open the door on exotic technologies, such as motion-sensitive walls that light up when a person comes near.
To make their flexible, paper-thin sensor, Javey's team started with an ordinary layer of silicon as the bed. Over that, they laid a thin sheet of polymer, called polymide. The sheet is like paper, Javey said - delicate to work with, but strong enough when it has support. Next, they tried two different techniques to "print" the electronics to the silicon bed.