Investigation of porous nanoparticle structures under illumination for the application as gas sensors

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Our long-term vision "Photologic" is the realization of a simple and compact sensor device, operated at room temperature, which enables the unambiguous detection of different gases in a gas mixture. The concept is based on a stacked multi-layered nanoparticle structure under illumination, where single layers are selectively activated with adequate wavelengths.While commercial resistive gas sensors are all operated at temperatures around 300°C, the effects of illumination on porous nanoparticle layers are completely different and need to be fundamentally understood for gas sensing and any (photo-) catalytic process in porous particle structures.In contrast to a constant temperature sensor, where the sensing properties are homogeneous across the particle layer, the light intensity within an illuminated layer decreases according to the Beer-Lambert law. Thus, the sensing properties depend on the actual position within the layer. The aim of our proposal is to fundamentally understand how this inhomogeneous illumination distributes within a porous particle layer and how this influences the mechanisms of gas sensing in comparison to the well understood effects in heated devices. By combining experiments and discrete element method (DEM) simulations, we expect to provide significant insights into the effects of illumination on the nanoparticle scale. This structural information would greatly enhance the understanding of the processes in porous nanoparticle layers under illumination. The gained knowledge enables the proof-of-concept for our Photologic device.