Oxygen (O2) is an essential gas not only for us and most other lifeforms, but also for many industrial processes, biomedicine, and environmental monitoring applications. Given the importance of O2 and other gases, many researchers have focused on developing and improving gas-sensing technologies. At the frontier of this evolving field lie modern nanogap gas sensors—devices usually comprised of a sensing material and two conducting electrodes that are separated by a minuscule gap in the order of nanometers (nm), or thousand millionths of a meter. When molecules of specific gases get inside this gap, they electronically interact with the sensing layer and the electrodes, altering measurable electric properties such as the resistance between the electrodes. In turn, this allows one to indirectly measure the concentration of a given gas.