Effect of Adsorption Mechanism on Conduction in Single-Molecule Pyrrole-Based Sensor for AFB1

We investigate through ab-initio simulations the gold-8PyrroleDiThiol-gold (Au-8PyDT) molecular quantum dot as an amperometric single-molecule sensor for the aflatoxin B1 (AFB1) detection. We study the chemical-physical interaction of AFB1 with the Au-8PyDT, and we analyze the transport characteristics of the four most probable adsorption configurations. We also investigate the link between transport modulation and adsorption mechanism. Interestingly, the investigated sensor exhibits conduction features similar to other types of quantum dot-based sensors. A significant current suppression occurs in all cases, with almost two orders of magnitude of current decrease in presence of AFB1 at 0.6 V. Considering the sensor robustness w.r.t. the specific adsorption configurations, our study motivates future research in this field.