1T and 2H mixed phase WS2 nanoflakes decorated with quasicrystal nanosheets for NO2 sensors

The development of new nanomaterials is immensely important for real-world sensing applications to improve the sensitivity, selectivity, and stability of the sensors devices. Herein, we explore the gas sensing properties of two-dimensional quasicrystal (2D QC) nanosheets and WS(2)nanoflakes. The decoration of chemically exfoliated QC nanosheets on WS2 nanoflakes significantly enhances their NO2sensing performance. This approach allows for detecting target gas molecules with exceptionally high sensitivity. For 20 ppm NO(2)at 1251C the DR/Ra% value for optimal amount of 2D QC nanosheets decorated WS(2)nanoflakes based sensors reaches 52%, which is a 233% higher response than that of bare WS2 nanoflakes sensors. The increased sensitivity of the 2D QC decorated device is due to the increased carrier concentration in WS2 caused by the Fermi level alignment and the high affinity of the QC towards NO2. Furthermore, the density functional theory (DFT) study revealed atomic insight into increasing the gas sensing response due to the presence of transition metals in 2D QCs, drastically enhancing the active sites for NO(2)adsorption; therefore, adsorption energy is boosted manifold compared to the WS(2)monolayer. This experimental and DFT study of NO(2)gas sensors provides detailed insight into gas sensors, and it would be very useful for the design of highly efficient NO(2)gas sensors