Highly sensitive and selective visual hydrogen detectors based on YxMg1-x thin films

We demonstrate how thin films of Y-Mg based alloys capped with a catalytic Pd layer can be used as an inexpensive device to visualize the presence of hydrogen at different concentrations. Using the change in the intrinsic optical properties of Y-Mg alloys upon exposure to hydrogen, combined with an interference effect due to a Pd cap layer, we obtain a device that can indicate the presence of hydrogen at concentrations as low as 20 ppm just by a reversible change in color. The eye-visible color change circumvents the use of any electronics in this device, thereby making it an inexpensive H