Touchscreens inevitably leaves fingerprints at best, germs at worst. GM was awarded a patent for a self-cleaning touchscreen that’s also self-disinfecting.
This system does not rely on the germicidal 254-264-nm UV-C wavelength used to disinfect water supplies, hospitals, airplane interiors, etc. Instead, ultraviolet illumination from LEDs activates a photocatalytic coating applied to the touchscreen. That material is normally water repellant, but when activated by UV light (sufficient sunlight can trigger it), it becomes hydrophilic, meaning it absorbs moisture from the air. With the moisture, the catalyst effectively kills and removes any organic material on the surface.
