By VSParticle
At VSParticle, we aim to bridge that gap through a novel manufacturing approach that offers precise control over material composition and morphology, while remaining clean, scalable, and reproducible. Our technology combines spark ablation with nanoprinting to deposit nanoporous MOS layers with exceptional control (Figure 2). In this dry process, a high voltage is applied across two conductive electrodes, generating a spark that vaporises electrode material. An inert gas that is flown through the electrode gap rapidly cools the vapor, condensing it into high-purity nanoparticles with tunable sizes (1-20 nm). The nanoparticle aerosol is then directed towards a substrate, onto which it forms nanoporous films or patterns. The solvent-free approach eliminates the need for wet chemistry, is inherently scalable, and allows for complex patterning on a wide variety of substrates, including sensitive MEMS chips. VSParticle's nanoprinting technology takes this a step further by using the smallest stable nanoparticles with sizes <20 nm, produced through spark ablation, to create MOS layers. This approach leads to structures with exceptionally high surface-area-to-volume ratios and significantly lowers the limit of detection (LOD), a key performance metric for gas sensors. A study by Sánchez-Vincente et al. [7] demonstrated that nanoporous ZnO and SnO₂ layers fabricated using spark ablation outperformed those made through conventional methods like drop-casting and electrospray, achieving lower detection limits (sub-ppm) for gases like CO and NO₂. VSParticle's nanoprinting technology addresses this challenge by providing unmatched flexibility in material selection and combination. The spark ablation process allows for any conducting material to be used as a nanoparticle source, and up to four different nanoparticle sources can be combined with precise control over their ratio. The technology enables easy exchange of electrodes or adjustment of the nanoparticle sources' output ratios. This facilitates the systematic exploration of combinations of metal oxides and noble metal dopants. With this material flexibility, the sensing layer composition can be tailored to optimize the detection of specific target gases such as formaldehyde, acetone, or carbon dioxide. By selecting the optimal material combinations, the sensor responses to particular gases can be fine-tuned – without the need to redesign synthesis processes or re-formulate inks. As a result, sensor designs can be rapidly iterated to optimize performance and achieve the desired selectivity VSParticle's nanoprinting method contributes to this by producing sensing materials with lower noise, a broad linear response across different gas concentrations, and improved repeatability when compared to sensors fabricated using traditional methods [7]. This enhanced reliability and reproducibility make spark ablation-based sensors particularly well-suited for accurate and consistent gas detection in practical environments. The reliable performance of these sensors is partly due to the highly uniform porous structure of the sensing material, which is consistently reproducible across different devices. Additionally, the surfaces of the sensing materials produced through nanoprinting are ultra-pure, because no solvents or binders are required in the fabrication process. Moreover, by avoiding complex lithography or etching steps, VSParticle's nanoprinting technology minimizes the risk of contamination and performance variability. To summarize, VSParticle's nanoprinting technology offers promising solutions to the fabrication challenges that have hindered the commercialization of e-noses. Lab-scale tests demonstrate the nanoprinting technology as a controlled and reproducible method to produce MOS sensing layers with high porosity, a wide range of material compositions, and complex patterning capabilities. This flexibility enables the creation of sensitive sensing units tailored to detect specific gases, which can be integrated into sensor multiarrays.
