Pd2+ doped ZnO nanostructures: Structural, luminescence and gas sensing properties

• Pd doped ZnO nanostructures prepared using sol–gel method.
• Strong violet-blue emission was observed.
• Sensing properties of undoped and Pd doped ZnO nanostructures towards NH3 and H2S gases.

We report on synthesis of Pd-doping of ZnO-nanostructures and its role on the gas sensing properties of NH3 and H2S. The complementary investigation aimed at understanding, explaining and confirming the role of Pd-doping on the surface morphology, photoluminescence (PL) and gas sensing behaviour exhibited at low gas concentrations were conducted. X-ray diffraction (XRD) analysis revealed a single-phase wurtzite structure of ZnO. X-ray photo-electron spectroscopy (XPS) results showed that partial Pd ions aggregate on the surface of ZnO while the rest are doped into the ZnO lattice. Surface morphology analysis revealed the increase in surface to volume ratio with the incorporation of the Pd-dopant into ZnO. The dominant violet-blue emission observed in the PL spectra of undoped and Pd-doped ZnO indicated the presence of Zni shallow donors resulting to improved sensing response.