Low-Cost, Large-Area Fabricated, Highly Sensitive, and Specific Plasmonic Hydrogen Gas Sensors Embedded in Large-Area Conductive Textiles and Wearable Jackets

In this paper, we describe highly sensitive plasmonic hydrogen sensors that are based on plasmonic nanohole arrays in gold films coated with a thin layer of palladium. These plasmonic hydrogen sensors operate at room temperature, which is very important for hydrogen sensing, as sensing at higher temperatures can lead to possible fires or explosions, as hydrogen is a highly flammable and potentially explosive gas above a certain concentration. We describe low-cost compact hydrogen sensors that are fabricated over a large area using nanosphere lithography. These compact hydrogen sensor chips are integrated into miniaturized capsules along with small LEDs and photodetectors such that these capsules can easily be attached to flexible conductive wires and threads or can be attached to an electronic textile fabric. The plasmonic hydrogen sensors being proposed in this paper are not only highly specific to hydrogen but also have a low limit of detection in the low ppm range. We also demonstrate a textile fabric based plasmonic gas sensing system, having multiple plasmonic hydrogen sensors attached to conductive threads embroidered on an electronic textile fabric, which has not been carried out previously. In this article, we also demonstrate a wearable textile jacket with multiple embedded plasmonic hydrogen sensors. Moreover, we demonstrate a wearable jacket with embedded plasmonic gas sensors such that light sources (LEDs) of different wavelengths are employed for sensing, providing multiwavelength sensing results. Sensing in different spectral regimes can also allow verification of the sensing results with those obtained by using a spectrometer, possibly alleviating the need for employing a spectrometer for carrying out the gas sensing work.