Layer-by-Layer Assembly of Porous 2D Metal-Oxide Architectures by Nanofabrication

Metal oxides (MOxs) commonly exhibit semiconductor behavior and chemoresistance, which enables their use as gas sensors. In our research, we have demonstrated the flexibility and adaptability of the layer-by-layer assembly of chemoresistive and catalytic filtering films. This method creates a highly integrated system¹ for the exclusive detection of critical gases. Among the various synthesis methods available, flame spray pyrolysis (FSP) is particularly interesting, as it can produce nanocrystals (NCs) and deposit them as highly porous thin films.² Here, we interface up to three layers of different metal oxides with closely controlled thicknesses onto Al2O3 substrates with interdigitated electrodes. We will show the strong effect of layer thickness and electronic coupling on the sensitivity and selectivity of chemoresistive sensors when detecting volatile organic compounds. This compact solution provides a flexible platform that can be tailored to a diverse range of analytes, empowering researchers to customize their gas sensing applications. Its high degree of integration also allows for its exploration of low-power, distributed solutions, broadening the applicability of MOx NCs in gas sensing.

1 Jeong, S.-Y. et al. A New Strategy for Detecting Plant Hormone Ethylene Using Oxide Semiconductor Chemiresistors: Exceptional Gas Selectivity and Response Tailored by Nanoscale Cr2O3 Catalytic Overlayer. Advanced Science 7, 1903093 (2020). https://doi.org/https://doi.org/10.1002/advs.201903093
2 Güntner, A. T., Pineau, N. J. & Pratsinis, S. E. Flame-made chemoresistive gas sensors and devices. Progress in Energy and Combustion Science 90, 100992 (2022). https://doi.org/https://doi.org/10.1016/j.pecs.2022.100992