(179c) Charge-Transfer Salt Nanowire Electrocrystallization for Ammonia Detection

Affordable sensors with better performance are required in different fields, such as environmental monitoring, safety, and homeland security. Nanowire sensors are considered as the promising next-generation sensors. Major technological gaps between the basic research and sensor market include the high cost and complicated process for making nanowire sensors. In this talk, we will present our ongoing research on the substrate-mediated charge-transfer salt nucleation and its application on nano/micro wire sensor manufacturing. Our research showed that small particles can direct nucleation of charge-transfer salt nanowires including tetrathiafulvalene (TTF) and tetracyanoquinodimethane (TCNQ). TTF-TCNQ is often recognized as the first organic metal. Using electrochemical crystallization, TTF or TCNQ charge-transfer salts with different counterions, can be directly deposited onto photolithographic substrates. By simply changing the crystallization conditions and counterions, nano/micro wire sensors of various detecting capabilities can be made and assembled into sensor arrays for gaseous chemical detection. One of our target gases is ammonia, which is considered the second most hazardous industrial gas. Our sensors can detect as low as 1 ppm ammonia in less than a minute. Our sensor arrays show enhanced selectivity towards mixed gases such as the selective detection against humidity after applying the deep learning algorithm. This work has been supported by the National Science Foundation, US Army Research Office, and MTRAC.