Smart gas sensor array (GSA) powered by machine intelligence is a machine equivalent olfactory system of mammalian noses. The abilities of such system to distinguish different species of gases and quantitatively measure gas concentrations in a mixture scenario are extremely important for pollution monitoring, hazard gases detection, food safety monitoring, etc. GSAs have attracted even more attentions with potential applications for breath analysis towards disease diagnosis at the point-of-care. The most widely used gas sensors are based on metal oxide (MOX) semiconductors suffering from high power consumption, poor selectivity, humidity susceptibility, and baseline drift. Zero-dimensional (0D) quantum dots (QDs) gas sensors are promising candidates that benefit from ultrahigh surface-t...[ Read more ]

Smart gas sensor array (GSA) powered by machine intelligence is a machine equivalent olfactory system of mammalian noses. The abilities of such system to distinguish different species of gases and quantitatively measure gas concentrations in a mixture scenario are extremely important for pollution monitoring, hazard gases detection, food safety monitoring, etc. GSAs have attracted even more attentions with potential applications for breath analysis towards disease diagnosis at the point-of-care. The most widely used gas sensors are based on metal oxide (MOX) semiconductors suffering from high power consumption, poor selectivity, humidity susceptibility, and baseline drift. Zero-dimensional (0D) quantum dots (QDs) gas sensors are promising candidates that benefit from ultrahigh surface-to-volume ratio and high sensitivity. Furthermore, functionalizing QDs with different chemicals and integrating with supporting circuitry will enable scalable fabrication of GSAs towards machine intelligent and wearable electronic nose.

In this work, I have successfully synthesized QDs ink and achieved different doping of materials through liquid-phase ligand exchange. The effectiveness of doping is demonstrated by different material characterization techniques and gas sensing performance of fabricated gas sensor arrays. I have also designed and fabricated an electronic nose system for 16-pixel sensor array that is capable of reading and wirelessly transmitting signal to smart phone where gas analysis algorithms can be performed. Based upon such system, a fully wearable electronic nose system based on QDs gas sensor arrays is fabricated and demonstrated. From this, more hybrid materials will be explored through surface functionalization and utilized for the construction of smart GSAs. This would provide a novel gas sensing platform to tackle real life challenges hindering the applications of GSAs for Internet of things (IoT), wearable electronics, and breath analysis.