Black P-Graphene Heterojunction: Fast Response Humidity Sensor with Good Reversibility and Stability

초록

Particular attention has been paid to the two-dimensional (2D) black phosphorus (BP) owing to its interesting super sensitivity for humidity sensing thanks to natural absorption of water (H2O) molecules on BP surface and specific layer structure of 2D BP materials. However, humidity sensor based on BP has limitations of instability of BP in moisture, leading to non-repeatability and less stability of sensor. In this work, we overcome these limitations of BP?based humidity sensor by making BP-graphene heterojunction as novel humidity sensing nanostructures. The BP as superior sensitivity with humidity was used as “catalyst material” to develop humidity sensor on graphene backbone with keeping excellent sensing properties of BP with humidity but improving reversible factor and stability. The BP/graphene interface improved stability in humidity sensor upon few weeks with linear response in relative humidity (RH) range of 15 - 70%. The extremely fast response/recovery of humidity sensor is within few seconds. The response (S) of humidity sensor based on BP/graphene heterojunction is 43.4% at RH =70%. The estimated response and recovery time of sensor are only 9 and 30 seconds at RH =70% at room temperature. The experimental investigation reveals that BP/graphene heterojunction does not only improve reversibility and hysteresis factors but also enhance stability of humidity sensor