Hybrid MoS₂/PEDOT:PSS Sensor for Volatile Organic Compounds Detection at Room Temperature: Experimental and DFT Insights

This work emphasizes the gas sensing capabilities of MoS2/PEDOT:PSS nanohybrid-based sensors, offering a prominent candidate for detecting volatile organic compounds (VOCs) at room temperature. The MoS2/PEDOT:PSS composite material is synthesized by combining commercial PEDOT:PSS with MoS2 produced via hydrothermal synthesis using ultrasonication for mechanical mixing. Further, the pristine PEDOT:PSS, MoS2, and MoS2/PEDOT:PSS samples were extensively characterized using various techniques to obtain detailed information about their structural, compositional, and morphological properties. The study reveals that the MoS2/PEDOT:PSS composite exhibited the highest sensitivity among the tested materials with a 56.29% response at 500 ppm of ethanol. The response of the MoS2/PEDOT:PSS sensor increases from 12.24% to 56.29% as the concentration of analyte gas increases from 25 to 500 ppm. Also, repeatability-, sensitivity-, and humidity-based analyses were performed for the evaluation of the sensor. The response and recovery times of the MoS2/PEDOT:PSS nanohybrid sensor are 8.2 and 2.5 s, respectively. The repeatability analysis demonstrated stable performance across multiple tests with percent deviations of ±0.04 for PEDOT:PSS, ± 0.35 for MoS2, and ±0.08 for MoS2/PEDOT:PSS under ambient conditions. The computational study reveals that the EDOT:SS/MoS2 (002) composite exhibits strong oxygen adsorption energies of −11.61 eV, indicating enhanced adsorption capabilities. In contrast, MoS2 (002) and PEDOT:PSS show lower energies of −9.22 and −11.08 eV, respectively. Additionally, VOC adsorption on oxygen preadsorbed EDOT:SS/MoS2 (002) shows methanol and ethanol with strong affinities, while toluene and hexane exhibit weaker interactions. These computational findings highlight and support the potential of the MoS2/PEDOT:PSS composite for gas sensing applications.