Flexible MoS2 sensor arrays for high performance label-free ion sensing

We report the production of flexible integrated MoS2 ion sensor arrays (FIMA) which demonstrated excellent mechanical flexibility (strain limits of 1%) and stability (bending 1000 cycles). We systematically investigated the influence of strain on the sensing performance and underling mechanism of MoS2 sensors, which is critical to flexible devices. Strain variation from -0.17% to 0.17% resulted in 29% enhancement of ion sensitivity due to energy band change, indicating tunable sensing performance of MoS2 by strain applied. The low-cost simple-structured FIMA realized simultaneous and multiplexed detection of Na+, Cd2+, Hg2+, and Pb2+ at trace concentration with excellent selectivity. Rapid (8 s) label-free detection of Cd2+ was achieved with detection limit of 5 ng/mL. Flexible MoS2 sensor arrays also exhibited the capability of monitoring Hg2+ in tap water and Na+ in human sweat samples, respectively. The FIMA show promise to an essential sensing platform for flexible/wearable devices. (C) 2018 Elsevier B.V. All rights reserved.