Hybrid MoS<sub>2</sub>/PEDOT:PSS Sensor for Volatile\nOrganic Compounds Detection at Room Temperature: Experimental and\nDFT Insights

This work emphasizes the gas sensing capabilities of\nMoS<sub>2</sub>/PEDOT:PSS nanohybrid-based sensors, offering a prominent\ncandidate\nfor detecting volatile organic compounds (VOCs) at room temperature.\nThe MoS<sub>2</sub>/PEDOT:PSS composite material is synthesized by\ncombining commercial PEDOT:PSS with MoS<sub>2</sub> produced via hydrothermal\nsynthesis using ultrasonication for mechanical mixing. Further, the\npristine PEDOT:PSS, MoS<sub>2</sub>, and MoS<sub>2</sub>/PEDOT:PSS\nsamples were extensively characterized using various techniques to\nobtain detailed information about their structural, compositional,\nand morphological properties. The study reveals that the MoS<sub>2</sub>/PEDOT:PSS composite exhibited the highest sensitivity among the\ntested materials with a 56.29% response at 500 ppm of ethanol. The\nresponse of the MoS<sub>2</sub>/PEDOT:PSS sensor increases from 12.24%\nto 56.29% as the concentration of analyte gas increases from 25 to\n500 ppm. Also, repeatability-, sensitivity-, and humidity-based analyses\nwere performed for the evaluation of the sensor. The response and\nrecovery times of the MoS<sub>2</sub>/PEDOT:PSS nanohybrid sensor\nare 8.2 and 2.5 s, respectively. The repeatability analysis demonstrated\nstable performance across multiple tests with percent deviations of\n±0.04 for PEDOT:PSS, ± 0.35 for MoS<sub>2</sub>, and ±0.08\nfor MoS<sub>2</sub>/PEDOT:PSS under ambient conditions. The computational\nstudy reveals that the EDOT:SS/MoS<sub>2</sub> (002) composite exhibits\nstrong oxygen adsorption energies of −11.61 eV, indicating\nenhanced adsorption capabilities. In contrast, MoS<sub>2</sub> (002)\nand PEDOT:PSS show lower energies of −9.22 and −11.08\neV, respectively. Additionally, VOC adsorption on oxygen preadsorbed\nEDOT:SS/MoS<sub>2</sub> (002) shows methanol and ethanol with strong\naffinities, while toluene and hexane exhibit weaker interactions.\nThese computational findings highlight and support the potential of\nthe MoS<sub>2</sub>/PEDOT:PSS composite for gas sensing applications.