Energy-efficient NO2 sensors based on two-dimensional layered 2H-WS2 nanosheets

Abderrahim Moumen, Rajashree Konar, Dario Zappa, Eti Teblum, Gilbert Daniel Nessim, Elisabetta Comini

Research output: Contribution to journalArticlepeer-review

Abstract

Layered transition metal dichalcogenides (TMDCs) are considered among the next-generation materials for gas sensing. Here, we report exfoliated 2 H-WS2 nanosheets for the fabrication of highly performing NO2 sensors. Thermal annealing at several temperatures was performed to investigate the oxidation of WS2. The long-term stability of 2 H-WS2 bulk was verified. Using droplet variation method, three batches of conductometric sensors from 2 H-WS2 dispersions were fabricated on electrical transducers, namely two layers (2 L), five layers (5 L) and ten layers (10 L) WS2 nanosheets. These sensors were tested towards low NO2 concentrations at different temperatures (Room Temperature (20 ℃), 50 ℃ and 100 ℃) and relative humidity (RH) levels (20%, 40%, 60%, 80% and 90% RH). 2 L-WS2 based sensor showed the highest response at room temperature (RT). Excellent repeatability (4 cycles) towards 1 ppm NO2 and long-term stability (more than two months) were achieved. Full selectivity towards NO2 (1 ppm) at RT was observed over NH3 (15 ppm), H2S (15 ppm), ethanol (30 ppm) and acetone (30 ppm). Our results confirm that low-power consumption devices with high sensitivity (even at high RH), long-term stability and excellent selectivity towards NO2 were fabricated using 2 H-WS2 nanosheets.

Original languageEnglish
Article number135379
JournalSensors and Actuators B: Chemical
Volume406
DOIs
StatePublished - 1 May 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors

Keywords

  • 2 H-WS nanosheets
  • CVD
  • NO
  • Room temperature
  • Selectivity

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