High performance of the rare earth (Er, Gd & Pr) doped MoO3 thin films for advanced applications towards ammonia gas sensing

Abstract

In this report, an economical spray pyrolysis technique was used to develop pure and 2% of Er, Gd, Pr doped MoO3 thin films. Different characterization techniques were utilized to study the properties of the pure and 2% of Er, Gd, Pr doped MoO3 thin films. The structural XRD analysis revealed monoclinic crystal structure of the MoO3 thin films with high purity and highest crystal size of 59 nm for the Pr doped MoO3 thin film. Furthermore, the lattice constant values increase with the substitution of Er, Gd, Pr dopants in MoO3 thin films. The morphological studies revealed reticulated nano-fibrous mesh morphology for all the samples and tiny rod-shaped protrusions over the surface of Pr doped MoO3 thin film. The optical studies demonstrated lower transparency, small bandgap and important defects. The gas sensing studies established the good response of the Pr doped MoO3 thin film towards the NH3 gas of 1.34 × 104% (250 ppm) with high stability and fast response (54 s) with a recovery time of 12 s. This opens door to our synthesized Pr doped MoO3 thin film materials to be used for the construction of commercial ammonia gas sensors.