Picoliter Drop Deposition of SnO2 Nanoparticles onto Microsensor Platforms

Published

December 14, 2023

Author(s)

Elvin Beach, Kurt D. Benkstein, Krenar Shqau, Christopher Montgomery, Patricia Morris, Stephen Semancik

Abstract

Microhotplates produced by micromachining processes provide a robust substrate for miniaturized solid-state gas sensors; however, it can be challenging to locally deposit solution-suspended nanomaterials for sensing directly onto these small (≈ 100 µm), 3-dimensional platforms which are often configured in arrays to increase analytical capabilities. A picoliter drop-deposition technique based on ink-jet printing is described here which has been used to achieve accurate, precise drop placement and reproducible film formation. Tin oxide nanoparticles, a well-established sensing material for use in gas sensor devices, were used to demonstrate the methodology. The nanoparticles were synthesized via a hydrothermal route to achieve fully crystalline materials with an average diameter of 5.5 nm. Tin oxide nanoparticle-laden suspensions were then formulated to reduce agglomeration, enable consistent first-drop formation, and prevent dispenser clogging. A priming technique was developed to accurately and repeatably perform deposition of picoliter-range drops onto the microsensor platforms. The technique was employed with a dynamic drop placement procedure to yield formation of spatially-registered mesoporous oxide films on individual microhotplates. Microsensors fabricated with the drop-deposited SnO2 nanoparticles showed sensitive and rapid gas-sensing responses to several tested reducing gases at concentrations in the range of 5 µmol/mol to 100 µmol/mol. The presented results indicate that the combination of pre-formed nanoparticles and picoliter drop deposition offers a versatile approach for reproducibly manufacturing gas microsensors, which can be adapted for a range of gas sensing materials and microscale platforms.

Citation

Sensors and Actuators B-Chemical

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.snb.2023.135152

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Keywords

array, gas sensing, inkjet, microhotplate, microsensor, nanoparticle, tin oxide

Citation

Beach, E. , Benkstein, K. , Shqau, K. , Montgomery, C. , Morris, P. and Semancik, S. (2023), Picoliter Drop Deposition of SnO2 Nanoparticles onto Microsensor Platforms, Sensors and Actuators B-Chemical, [online], https://doi.org/10.1016/j.snb.2023.135152, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956662 (Accessed September 3, 2025)