Ammonia sensing properties of V-doped ZnO:Ca nanopowders prepared by sol–gel synthesis

•V-doped ZnO:Ca nanopowders with different V loading were prepared by sol–gel synthesis.•Raman features of V-doped ZnO:Ca samples indicate the substitution of V ions in the ZnO lattice.•Combined effects of dopants have brought to an enhanced response to NH3 compared to ZnO.•Ca play a key role in enhancing the sensor response of ternary V-doped ZnO:Ca composites.

V-doped ZnO:Ca nanopowders with different V loading were prepared by sol–gel synthesis and successive drying in ethanol under supercritical conditions. Characterization data of nanopowders annealed at 700 °C in air, revealed that they have the wurtzite structure. Raman features of V-doped ZnO:Ca samples were found to be substantially modified with respect to pure ZnO or binary ZnO:Ca samples, which indicate the substitution of vanadium ions in the ZnO lattice.The ammonia sensing properties of V-doped ZnO:Ca thick films were also investigated. The results obtained demonstrate the possibility of a fine tuning of the sensing characteristics of ZnO-based sensors by Ca and V doping. In particular, their combined effect has brought to an enhanced response towards NH3 compared to bare ZnO and binary V-ZnO and Ca-ZnO samples. Raman investigation suggested that the presence of Ca play a key role in enhancing the sensor response in these ternary composite nanomaterials.

Graphical abstractV-doped ZnO:Ca nanopowders prepared by sol–gel synthesis possess enhanced sensing characteristics towards NH3 compared to bare ZnO.Figure optionsDownload full-size imageDownload as PowerPoint slide