Explosives Detection Using Octanethiol Gold Nanoparticle Inkjet Printed Devices.

This study focuses on implementing 1-octanethiol gold nanoparticles (OT-AuNPs) as chemiresistive sensors and comparing fabrication by inkjet-printing with conventional drop-casting to detect volatile organic compounds (VOCs) and explosives including HMTD, PETN, KClO3, TATP, RDX, TNT, and UN. Inkjet-printing technology potentially offers more controlled deposition of OT-AuNPs and more uniform sensor properties compared to a drop-casting process. Using inkjet-printing, we found that a minimum of 600 OT-AuNPs printed layers with 2.4 pL drop volume, 9 drops per layer, and 60 μ m drop spacing was sufficient to reduce chemiresistor device baseline resistances to around 1 0 3 Ω and obtain more consistent responses. By contrast, 12 μ L OT-AuNPs drop-casting yielded device resistances spread over a range of 1 0 2 − 1 0 6 Ω due to uneven deposition. For inkjet-printed devices, higher response magnitudes with lower variability were achieved for explosive vapor detection whereas a larger spread was observed for drop casting. The improved uniformity of baseline resistances and sensor responses indicates inkjet-printed devices were more reproducible and repeatable than drop-casting. In addition, inkjet-printing consumes lower amounts of OT-AuNPs for material and cost savings. The results demonstrate that inkjet-printed devices are promising for use in sensor arrays to fabricate electronic noses for VOCs and explosives detection. [ABSTRACT FROM AUTHOR]