Tunable Volatile-Organic-Compound Sensor by Using Au Nanoparticle Incorporation on MoS2

Controlling the charge concentrations of two-dimensional (2D) materials is a critical requirement for realizing versatility and potential application of these materials in high-performance electronics and sensors. In order to exploit the novel chemical-sensing characteristics of 2D materials for sensitive and selective sensors, various functionalization methods are needed to ensure efficient doping of channels based on 2D materials. In the present study, the gas-sensing performance of MoS2 has been significantly enhanced by controlled Au nanoparticle functionalization. By using the difference in reduction potential between the Au precursor and MoS2 work functions, MoS2 prepared by chemical exfoliation process was decorated with nanoparticles with sizes of tens of nanometers. The n-doping effect of Au nanoparticles was observed, that is, these particles were found to have facilitated in electron charge transfer from Au to MoS2. The controlled n-doping effect enables the tuning of the sensing of hydrocarbon-based volatile organic compounds (VOCs) and oxygen-functionalized compounds by MoS2. A significant step has therefore been made with this study toward solving the limitations imposed by previous MoS2-based sensors, which mostly produce a single response to various VOC analytes. This controllable chemical doping process for tuning the VOC-sensing performance of MoS2 can eventually be used in early detection using multichannel sensing systems that have different responses and recognize patterns for target analytes.