Through the implementation of real-time impedance spectroscopy and development of a circuit model with physical meaning, redox exfoliated MoS2 nanoflakes demonstrate an ultrasensitive empirical detection limit of NO2 gas at 1 ppb, with an extrapolated ultimate detection limit approaching 63 ppt. This sensor construct reveals a more than three orders of magnitude improvement from conventional DC sensing approaches as the traditionally dominant interflake interactions are bypassed in favor of selectively extracting intraflake doping effects. This same approach allowed for an all solution-processed, flexible 2D sensor to be fabricated on a polyimide substrate using a combination of graphene contacts and drop-casted MoS2 nanoflakes, exhibiting similar sensitivity limits. Finally, material changes via annealing, selective coatings, and practical considerations for a mass-producible sensor will be discussed.

Ultrasensitive molecular sensors based on real-time impedance spectroscopy in solution-processed 2D materials

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.