Sensing Hydrogen Gas from Atmospheric Pressure to a Hundred Parts per Million with Nanogaps Fabricated Using a Single-Step Bending Deformation

Abstract

The widespread use of H2 gas as an energy carrier will necessitate the development of inexpensive, easily manufactured sensors which reliably monitor gas levels where H2 is used, transported, and stored. Nanogap sensors transduce the volume expansion which accompanies hydrogen uptake by palladium-based metal-hydrides into an electrical signal through the closure of nanogaps which allows a previously interrupted current to flow. While this break-junction design offers numerous functionalities, limitations still exist in terms of fabricating nanogap sensors responsive to a wide range of partial pressures. Here, we invoke a detection strategy where up to 10 000 nanogaps of various widths act in concert to provide an overall analog signal which continuously varies as the H2 partial pressure is varied from a hundred parts per million to 1 atm. The sensor is fabricated by mechanically coupling an AuPd film to a support consisting of polyimide, an adhesive, and a steel backing which, when bent, forms parallel cr...