Nano For Noncontact Touchscreens

LMU chemists develop nano-layers which change color when wet. With the new material interactive screen surfaces could be navigated without contact.

LMU chemist who first developed photonic crystals made ​​of thinnest nanolayers that are extremely sensitive to moisture. "They change their color depending on the humidity. This makes them ideal for the development of so-called touchless devices that can be controlled without touching, "says Professor Bettina solder from the Department of Chemistry at the LMU and the Max Planck Institute for Solid State Research. On their results report the LMU chemist currently in the journal AdvancedMaterials.

"The human finger is surrounded by a moisture atmosphere," says Katalin Szendrei from the research group of Professor solder the principle of new photonic sensor."Our sensor detects the level of moisture and responds with a corresponding change of color - without touching." This makes the new nanomaterial for use in contactless touchscreen interesting. "Especially with screen surfaces, which are used by many people, some of ticketing or ATMs, have a contactless navigation significant hygiene benefits," Szendrei describes one possible application.

New system offers unmatched sensitivity and response times

Photonic crystals are found for example in pearl or the colors of butterfly wings in nature. The team led by solder, it is possible to develop photonic crystals based on two-dimensional antimony phosphates as active materials. The new nanomaterial is chemically stable, establish transparent and simple. Compared to other sensors at the nano-layer base convinced the photonic crystal through faster response, a much higher sensitivity and good long term stability. "This unique combination of properties makes it possible to finger movements in real-time color-coded map," said Pirmin Ganter from the Working Group of Bettina solder. In addition, the new system is air-stable and thus not only in the laboratory, but also under natural environmental conditions fully functional.

The LMU chemists have already filed a patent for their new development.Meanwhile, they are working together with the Fraunhofer EMFT in Munich at the realization of a prototype, which allows in addition to the color coding and an electronic read-out operation.