Multifunctional characteristics of polypyrrole-zinc oxide (PPy-ZnO) nanocomposite: Field emission investigations and gas sensing application

•The nanocomposite Polypyrrole-ZnO nanorods were successfully synthesized using facile chemical and electrochemical route.•The PPy-ZnO nanocomposite exhibits better multifunctional characteristics in field emission and gas sensing application.•The enhanced FE characteristics are due to contribution π electrons from polypyrrole•Superior sensing properties of composite is attributed unique morphology and formation p-n junction. Multifunctional behavior of Polypyrrole-Zinc oxide (PPy-ZnO) nanocomposite, synthesized by chemical and electrochemical routes, towards field emission (FE) and ammonia (NH3) sensing has been investigated. The preparation of the nanocomposite embraces the specific motivation of subsuming 1-dimensional (1D) form of the ZnO nanorods with PPy. The morphological, structural, chemical and optical analysis of the PPy-ZnO nanocomposite has been done employing various characterization techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), Fourier Transform Infrared (FTIR), Raman, UV–vis and Photoluminescence (PL) spectroscopy. The field emission (FE) investigations of PPy-ZnO nanocomposite exhibited lower values of turn-on and threshold fields (3.1 and 4.5 V/ μm, respectively) along with competency to deliver current density of ∼1.5 mA/cm2 at relatively lower applied field of ∼6.5 V/μm. The superior FE behavior of PPy-ZnO nanocomposite emitter is attributed to synergic effect of unique morphology and electrical property (enhancement in charge carrier density). Furthermore, NH3 sensing characteristics of pristine ZnO nanorods and PPy-ZnO nanocomposite thin films, were studied under static condition. Interestingly, the PPy-ZnO nanocomposite showed promising NH3 sensing characteristics, as compared to the pristine ZnO nanorods and other nanocomposites. The present attempt towards synthesis of organic-inorganic nanocomposite exhibiting promising multifunctional behavior can be extended to explore alike nanocomposites.