Synthesis and Characterisation of ZnO–Ag Thin Films and Their use as Ammonia Sensors

Authors

  • Mohammed Bandr Abdullwahed , Ahmed Mishaal Mohammed * , Firas Fadhel Ali

Abstract

This study involves the preparation of colloidal silver (Ag) nanoparticle solution using Turkevich
method. Specifically, the solution is mixed with the zinc nitrate hexahydrate and
hexamethylenetetramine solution with various volume ratios (e.g. 50, 70 and 90 AgNPs %V) to
deposit zinc oxide (ZnO)–Ag thin films on glass substrates at 350 °C using chemical spray pyrolysis
technique. Then, these thin films are used to measure the sensitivity of ammonia (NH3) at room
temperature (30 °C–32 °C). The thin films formed by this technique have been characterised by the
following measurements: FE-SEM, XDR, AFM and EDXA; whereas, AFM, UV-Visible
spectrophotometer and FT-IR spectrophotometer have been used to characterise the prepared Ag
nanoparticles. The average size of ZnO–Ag nanoparticles formed on glass substrates is within the
range of 68.93–86.64 nm, whereas the average size of Ag nanoparticles formed through Turkevich
method is 48.9 nm. The XRD measurements show the wurtzite hexagonal and face centred cubic
crystal structure of ZnO and Ag, respectively. The thin film that contains 50 %V of Ag has the
highest gas sensitivity (69%). The high sensitivity of the ZnO–Ag sensor at room temperature is an
indicator of the high efficiency of NH3 gas sensing.

Published

2020-10-14

Issue

Section

Articles