High performance acetaldehyde gas sensor based on p-n heterojunction interface of NiO nanosheets and WO3 nanorods

P-N heterojunction based chemi-resistive sensor is designed by incorporating NiO nanosheets (NSs) into WO3 nanorods (NRs) with high aspect ratio. The nanostructured NiO and WO3 were synthesized by facile hydrothermal chemical route and well-characterized by using XRD, FESEM, EDS, XPS, Raman, and elemental mapping. These two materials mixed in different weight ratio viz 5:95, 15:85, and 25:75 to fabricate the sensors named NW1, NW2, and NW3, respectively. The fabricated sensors were investigated for gas sensing properties at different operating temperatures. All the sensors revealed a high response towards acetaldehyde among various gases at 250 degrees C. Among these sensors, NW2 exhibited the highest response of 2184 % for 100 ppm acetaldehyde concentration at 250 degrees C and revealed a high response for 20-100 ppm acetaldehyde range. The NW2 sensor also showed excellent transient resistance response for different concentrations of acetaldehyde gas in real-time. The consistent response of the NW2 sensor for 100 ppm acetaldehyde was dynamically observed and confirmed remarkable repeatability in real-time. The high response and selectivity of the NW2 sensor are due to the p-n heterojunction formed at NiO and WO3 interface. The hypothesized acetaldehyde sensing mechanism was explored and the stability of the NW2 sensor was tested. This p-n heterojunction-based nanostructure can be promising to design high-performance acetaldehyde sensing application.

Automated summary

A chemi-resistive sensor based on P-N heterojunction was designed by incorporating NiO nanosheets into WO3 nanorods. Among the sensors fabricated with different weight ratios, NW2 exhibited the highest response for 100 ppm acetaldehyde concentration at 250 degrees C and showed good stability and repeatability. The high performance of NW2 sensor is attributed to the formation of the p-n heterojunction between NiO and WO3, making it a promising candidate for acetaldehyde sensing applications.