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

我们的长期愿景是实现一种简单紧凑的传感器设备，在室温下运行，从而能够明确地检测到混合气体中的不同气体。这一概念基于堆叠的多层纳米颗粒结构，在光照下，单层被选择性地激活，并具有足够的波长。虽然商用阻性气体传感器都在300°C左右的温度下工作，但照明对多孔纳米颗粒层的影响是完全不同的，需要从根本上了解多孔颗粒结构中的气体传感和任何(光)催化过程。与恒温传感器不同，恒温传感器的传感特性在颗粒层上是均匀的，照明层内的光强度根据比尔-朗伯定律下降。因此，感测属性取决于层内的实际位置。我们建议的目的是从根本上了解这种不均匀照明是如何在多孔颗粒层中分布的，以及与众所周知的加热设备中的影响相比，这如何影响气体传感的机制。通过结合实验和离散元方法(DEM)模拟，我们希望对光照对纳米颗粒尺度的影响提供重要的见解。这种结构信息将极大地提高对多孔性纳米颗粒层在光照下的过程的理解。所获得的知识使我们的光学仪能够进行概念验证。

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.