Laser Ablated Gold Nanoparticles Incorporated in PVA Films for Enhancing Their Electrical Conductivity and Ammonia Gas Detection.

An optimized gas sensor that operates at room temperature is highly suitable for industrial safety applications. Polyvinyl alcohol (PVA) was embedded with gold nanoparticles (Au NPs) to produce the ammonia (NH3) gas sensor. These films were synthesized successfully using two different stages: (1) pulsed laser ablation in liquid method to prepare Au nanoparticles, and (2) solvent casting method to embed nanoparticles into PVA substrates. The gas detection capability of the films was investigated based on their optical, morphological, structural, crystallographic, and dielectric features. Field emission scanning electron microscopy confirmed nanoscale and well-dispersed Au NPs within the PVA substrate. X-ray diffraction analysis showed crystallinity improvement from 44.91% (pure PVA) to 76.41%. UV-visible spectroscopy confirmed the slight decrease in the optical bandgap from 4.89 eV to 4.27 eV. The dielectric measurements exhibit enhanced electrical conductivity of PVA embedded with 3% of Au nanoparticles, which is directly correlated with the improvement of gas sensing capability. The sensor exhibited an effective response of around 64.2% and had a sensitivity of 1.62 with a response time of 6s at room temperature under a 600 ppm NH3 gas concentration. That showed a greater sensitivity compared to pure PVA film.