Ultra-sensitive H2S gas sensors based on p-type WS2 hybrid materials

Nano Research Accepted, (2018)

Ultra-sensitive H2S gas sensors based on p-type WS2 hybrid materials

Georgies Alene Asres, José J. Baldoví, Aron Dombovari, Topias Järvinen, Gabriela Simone Lorite, Melinda Mohl, Andrey Shchukarev, Alejandro Pérez Paz, Lede Xian, Jyri-Pekka Mikkola, Anita Lloyd Spetz, Heli Jantunen, Ángel Rubio,, Krisztian Kordas

Owing to their higher intrinsic electrical conductivity as well as better chemical stability in reference to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor applications. Herein, we explore the gas sensing behavior of WS2 nanowire-nanoflake hybrid materials and demonstrate their outstanding sensitivity (0.043 ppm-1) as well as selectivity towards H2S in reference to CO, NH3, H2 and NO (with corresponding sensitivities of 0.002, 0.0074, 0.0002 and 0.0046 ppm-1, respectively). The gas response measurements complemented with X-ray photoelectron spectroscopy analysis and first-principles calculations based on density functional theory suggest that only the intrinsic electronic properties of pristine WS2 only are not sufficient to explain the observed high sensitivity towards H2S, whereas it is O doping in the S sites of the WS2 lattice that plays the major role. The present results of our study open up new avenues for the exploitation of transition metal disulfide nanomaterials as competitive counterparts of metal oxides in future applications for industrial process control, security as well as health and environmental safety.

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